73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Spool on January 18, 2018, 08:04:58 PM
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Hey guys,
73' C20 here.
It's been far too long since I've worked on my truck or the forum, August to be exact.
Specifically because I took on too much school and work simultaneously.
However, I'm back on the truck and appreciate all of you.
My truck died at a stop sign 300 yards from my house.
2 nights before that; it ran out of gas as I have a broken fuel gauge and I lost track of my mileage.
It started fine, took it around the block and then it died in which I lost power steering and brakes.
I'm thinking a fuel pump? What do you guys think?
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Let me drop a couple of coins into my crystal ball....
...Well...
That didn't work.... :o
Will the engine start and run? Are you certain it has adequate fuel in the tank, now? You should verify spark and then fuel. Pull a wire off of a spark plug and hold the open end near the exhaust manifold while an assistant cranks the engine. Does it produce a bright blue spark? Can you start and keep the engine running if you mist a little starting fluid or aerosol carburetor cleaner into the carburetor? If you let a drop of engine oil fall onto a clean fingertip from the dipstick, does it hold a tight circular shape or track outward along your finger ridges?
Why not rent a proper test gauge and check the fuel pump draw (>20" Hg of vacuum), pressure (~7 PSI) and delivery volume (>1 qt in 30 seconds of cranking)? That way you'll know whether the fuel pump is the issue rather than guessing. :)
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Thanks BD.
The engine will not start. It cranks but will not turn over.
There is roughly 5 gallons in the tank; 1/4 tank.
I removed the air filter and sprayed a touch of starting fluid in the carb with no avail.
My last oil change was 6 weeks ago (20/50) and the color is good. The drop stayed on my finger tip when I tested with the dipstick.
Now for my newbie questions as I've never worked with my spark plugs.
How do I remove it correctly and does it matter which one I check?
Per your instructions, am I to remove the spark plug, hold the wire connected to the spark plug away from the block/carburetor and observe the color of the spark while someone else turns the ignition?
Thank you as always.
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Just FYI - The words "cranking" and "turning over" with regard to an engine convey the same basic meaning. I think you meant to say the engine cranks (turns over) but doesn't start.
Any idea how many miles are on the spark plugs or when the last major tune-up was performed?
There are several ways to check spark, but they all amount to the same thing. Assuming you have a conventional (non-HEI) ignition system, with the engine cool remove the coil wire from the distributor cap. Grasp the coil wire with your fingers as far away from its free end as you can and hold it 3/8" - 1/2" away from a bare metal ground. Have an assistant crank the engine. Be sure to keep your hand away from the free end of the coil wire to prevent an eye-opening shock. A healthy conventional ignition system should generate a blue spark across a free air gap of up to about 1/2" wide. After you verify adequate spark remove a spark plug for a visual inspection of gap wear. Post a clear pic of the spark plug and its gap if you can. Note that when removing or installing spark plugs, always use an appropriately sized spark plug socket containing a rubber insert and a ratchet with a suitable length extension to prevent cracking the plugs.
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It's been years since a major tune-up.
I don't know much about the distributor but when you helped me re-wire my starter a few months ago, I remember we determined the distributor was HEI.
Do I need to remove power to my distributor before checking spark on a spark plug?
I have a neighbor who may be able to help me with this, but may I ask...
Are my spark plugs inside the engine? I was expecting a grab/twist/pull action.
Am I to expect something similar to this dry video?
https://www.youtube.com/watch?v=Zeq_8b3uzhg
EDIT**
Perhaps this video? More informative:
https://www.youtube.com/watch?v=L2bOqOhpqrg
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The spark plugs are located in the cylinder heads, directly below the exhaust manifolds - four each on opposite sides of the engine. With HEI the process of checking spark is a little different since there is no coil wire and voltage production is much greater. Leave the power lead connected to the distributor. With a cold engine, grab the spark plug boot of the most accessible spark plug wire. Give the boot a half-revolution twist back and forth to break it loose from the spark plug then pull the boot and wire toward you to separate them from the spark plug. Slip the boot up the wire to expose the metal terminal end of the wire. Grasp the wire at least 6" away from its free end to prevent a nasty high voltage shock. Hold the free end of the plug wire 1/2" - 3/4" away from a bare metal ground (such as the exhaust manifold) while an assistant cranks the engine. HEI should produce a bright blue spark across a free air gap of up to about 3/4". As mentioned earlier, remove and check the spark plug associated with the wire you removed. Post a pic of the plug if you are able.
Unfortunately, I'm experiencing Internet crawl this evening and cannot access the youtube video you linked.
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Got it.
So I'll be looking at the end of the wire after slipping the boot back in order to observe the color of the spark.
Meaning the spark plug itself, is still inside the engine? I would need a spark plug ratchet to remove that?
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Both of the videos you linked convey the general idea to R&R spark plugs (as long as you realize they are picturing only half an engine ;D ).
Besides slipping the boot up the wire, you will also remove the wire from the spark plug. Then hold the plug wire terminal 1/2" - 3/4" away from a bare metal ground while an assistant cranks the engine. Be sure to keep your hand a respectable distance from the bare end of the spark plug wire. If you forget and grab the wire too close to the end, you won't have any trouble remembering in the future! To remove spark plugs from the engine and reinstall them without damage, you will need a spark plug socket with a rubber insert, a 3" - 6" extension, and a ratchet (3/8" square drive flex-head ratchets work best). If you have to procure the tools, best to pick up a spark plug gap gauge at the same time (attached images - I prefer the wire type gauge).
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Much easier than expected and no one was shocked; I love learning this stuff.
However, no luck on getting the truck started.
Taking your advice and removing the spark plugs, I realized they were dirty, grimy and some of them, even rusty.
So I took a trip to AutoZone and picked up 8 new ones; ACDelco made of copper. The same type I removed.
However, after replacing them all, the truck still wouldn't start.
My neighbor came to help but we observed no spark with the new spark plugs.
Two questions on installing spark plugs if I could?
1. Do you know the gap measurement for a spark plug on a 350/4Barrel? The ones I removed were .30 and I settled for .40 on the new ones after referencing a few
other topics here on the forum.
2. Do you happen to know the torque specs for tightening a spark plug? I made it carefully snug for now as my service manual gave no specific torque; it simply said "adjust spark plugs and torque to specifications"
My spark plug cables don't look all that great either; even inside the boot is looking a little beaten and tired.
Think my distributor could be shot?
I've attached photos. Thanks BD.
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Spark plug gap should be set to 0.045"; torque spec for the plugs is 22 ft-lbs.
Regarding this image of the spark plugs...
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38240;image)
Post another image that better shows the electrodes and gaps of the plugs you removed. Did the spark plug terminal ends inside the boots of the wires appear sooty or discolored with greenish colored ash?
With the ignition switched on, check for 12.6 volts on the primary feed wire connecting to the distributor. Remove the distributor cap and visually inspect inside the cap and the rotor for wear, heat damage, ash buildup and carbon tracking. Post some pics.
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Thank you.
I noticed in the manual it said not to bend the spark plug to adjust measure;
Would I use a filer to go wider from .40 to .45 or do you think I could get away with just pushing it a little bit?
I've attached better photos of my the old spark plugs and my progress on the distributor.
I didn't see anything green colored ash on the spark plugs, but they certainly are sooty.
As for the Distributor, I numbered them all before removing them but noticed one of them is terribly corroded as you'll see in the photo.
Also, I couldn't get a solid reading on the primary feed wire.
I grounded out my multi-meter before grounding the negative, but when I begin prodding the primary feed it's anywhere from 2.0 to 7.0 and sometimes 22.0
I remember when we were working on my starter configuration we found that there was a split on the 3/7 circuit with a resistant wire still in place instead of the necessary 12v straight from the bulb head. I'll copy/paste those comments below.
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This was a part of our conversation from "Topic: 73 GMC Truck Wiring Diagrams/Battery Cables"
I've attached the photos. It's still in garbage condition...
I recall leaving the split as it was; but maybe it's time to power that straight from the bulkhead?
^^^ More than likely the 20-gauge yellow wires running between the starter, distributor and bulkhead connector will need to be stripped out and a new 12-gauge wire running between the bulkhead connector and distributor will need to be substituted. This will ensure that the HEI system receives suitable primary power.
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I'm taking a conservative approach hereon out (one-step-at-a-time) to try and minimize confusion.
Step 1 - Verify that the distributor is actually receiving full battery voltage with the ignition switched on. Set your voltmeter to its 20 VDC scale. Clip the negative lead of your voltmeter to the battery negative terminal (B-). Probe the battery positive terminal with the meter's positive lead to verify you have a good connection to B-. The meter should indicate 12.6 VDC if the battery is fully charged. Now, move the meter's positive lead to the wire connected to the BAT terminal of the HEI distributor and switch the ignition on. What is the voltage reading?
Post a clear, close-up pic of the inside of the distributor cap.
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I will gladly and appreciatively follow your lead.
The battery is brand new; I swapped it out a few days ago when I thought that might be the issue.
I use the DCV function on my multimeter. (Is this the same as VDC?)
I've attached photos showing the readings.
When taking the readings of the power lead to the distributor, the negative lead was on B- at the battery.
You'll see my voltage readings are all over for the distributor, even after cancelling out my terminal leads to zero and trying again.
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You either have a poor connection between the meter positive probe and the I+ wire feeding the distributor or an erratic connection somewhere in the I+ wire. To easily determine which, try using your incandescent test light instead of the meter.
The reason for substituting the test light is that the voltmeter doesn't impart a significant current load on the circuit under test. The resistance of the meter is so high that all of the circuit voltage is used across the meter. A poor connection that introduces unwanted resistance elsewhere in the circuit can prevent the circuit from functioning and yet not show up on a voltmeter as low voltage. An incandescent test light, on the other hand, demands sufficient current to illuminate the bulb that circuit voltage will be divided between the bulb and the unwanted resistance, causing the bulb to be dim.
DCV is Direct Current Volts and synonymous with VDC (Volts - Direct Current).
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Thanks BD.
What is my meter positive probe and the I+ wire?
As per the photos of inside the cap of my distributor Which one is considered inside?
I was confused while talking to my neighbor as to what is considered the cap as well.
He described it as the whole top part that comes off when removing the 4 screws that keep it in place; is this correct?
Are either of the photos I attached a proper photo showing the inside of my distributor cap or should I be looking elsewhere?
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The positive probe is the red meter lead.
I+ is Ignition Positive (or 12 volts, only when the ignition is switched on)
The top image shows the coil with its plastic dust cover removed.
In the lower image, you removed the distributor cap to snap a picture of the rotor. Now, flip the distributor cap upside down and take a clear closeup pic of the underside of the cap.
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Thanks BD.
I attached photos with notes this time around.
In short it seems like my power feed cable is garbage and should be replaced with a new 12gauge wire straight from ckt 3 in the bulkhead connector to the
distributor as you mentioned in one of our previous conversations. What do you think?
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(Please forgive the horrible grammar in my photoshop notes)
Also, I forgot to add a picture of the inside of my distributor cap.
It looks fairly clean, but I noticed there are markings on each metal contact after years of use.
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(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38286;image)
^^^^ There is the cause of the no spark condition. Run a temporary jumper lead from battery positive to the BAT terminal in the distributor cap. Chances are it will start, or at least produce a secondary spark. After the engine starts, you will need to disconnect the temporary jumper to kill the engine.
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38294;image)
^^^^ The light gray ash deposits on the spark plug wire terminals protruding inside the cap are normal and no cause for concern. However, it appears the carbon button in the center of the cap is eroded away. That carbon button is the contactor brush that transfers voltage to the rotor. Before you're done with the repair you should replace the distributor cap and rotor...
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38248;image)
^^^^ The white oxide that is coating the spark plug wire tower of the distributor cap is a result of ozone erosion due to minor arcing between the aluminum terminal of the tower and the wire. Replace the spark plug wires too with a good quality set. Smear a film of dielectric compound (https://www.summitracing.com/parts/lct-37534) on the terminals before snapping the new wires down onto the towers. You should smear a sparing amount inside of the spark plug boots as well to ease future removal of the wires. Otherwise, the boots can stubbornly adhere to the porcelain of the plugs.
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Thank you!
So the problem with it receiving power is the power feed.
I don't have an appropriate jumper lead at the moment, what if I were to cut out the wire and replace ckt 3 straight to the distributor with a new 12guage wire?
Do you think this would allow me to start the engine?
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(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=35286.0;attach=36941;image)
Remember this ^^^^ ? Follow the red ignition feed all the way back to the firewall bulkhead connector and probe the wire there. Will the test light illuminate? If it does then replace the complete wire between the distributor and bulkhead using 12-gauge stranded copper wire with SXL, GXL or GPT insulation (pink preferred, red will work).
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Perfect. I did exactly that.
Back then I took the split apart as the yellow wire splitting off no longer had a connection at the starter.
I was able to start the truck just now by cutting out the two poor connections and adding a temporary connection between the 12gauge wire from the distributor and the resistor wire coming from ckt 3 at the bulkhead.
Now that we know what the problem is and having it temporarily resolved, I'll replace what you mentioned.
First, I need to clean my bulk head connector to be able to remove the connection without damaging anything.
It's currently full of dirt and grime as the previous photo shows.
I picked up a can of CRC QD Electronic Cleaner for this.
I'll certainly pick up new new cables, a distributor cap and rotor.
Starting with the distributor cap, is there anything to look out for to ensure I buy the same one that fits? A model number of sorts?
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ACDelco D336X distributor cap and D448X rotor, or equivalent. Don't skimp on the spark plug wires either. A good set will provide longlasting service and not separate from the metal terminal ends during subsequent removal.
Make sure you pay attention to the order that parts are removed when swapping the old ignition coil to the new cap. The distributor cap will come with a new carbon button and silicone gasket. The order of assembly is to insert the new carbon button into the center hole of the cap from above, then the gasket, then the coil. Don't neglect to transfer the coil ground strap into the new cap.
QD probably won't remove the dry, dark brown antioxidant caked into the bulkhead connector. You will need some carburetor cleaner or engine starting fluid for that purpose. Be sure to repack the terminal cavity with antioxidant paste during reassembly to reject the intrusion of moisture and dust. Solder the terminals to the wire ends after you crimp them to minimize gradual oxidation and ensure consistent electrical connections. The primary lead feeding the distributor should be dedicated solely to that purpose and not be used to power any other appliance. Use the proper plastic connector that will engage and lock into the distributor cap so that it doesn't shake or pull loose while driving.
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Thank you, BD.
Out of my own curiosity, do you happen to know what Delco Remy is?
Is it a side-brand of sorts of ACDelco?
What are you thoughts on this?
https://www.summitracing.com/oh/parts/pro-66945bkc/overview/
It's a $50 price difference, but do you think it would be a good investment to replace a few other parts (wires/vacuum) on the distributor cap while I'm at at?
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https://en.wikipedia.org/wiki/ACDelco
http://www.delcoremyhistory.com/history.htm
http://www.delcoremy.com/
As to the link you posted for the Proform kit at Summit Racing, I do not recommend that route for you.
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Thanks BD.
I should have researched that on my own before asking, but I do appreciate the links; I'll read them this evening.
As always, thank you again for everything.
(I may have a few questions about the bulk head connector soon. Out of respect to the forum, would you prefer that in a new topic thread?)
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As long as the topic is related to this "no start/no spark" issue, continue it here.
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I didn't expect Amazon to have such items available, but they offer the cap and rotor with delivery tomorrow which is excellent.
In regards to cables, would this suffice or rather, are they a good choice?
I would prefer quality that doesn't break the bank. What would you recommend?
https://www.amazon.com/ACDelco-618W-Original-Equipment-Spark/dp/B000BYD3EK/ref=au_as_r?_encoding=UTF8&Make=Chevrolet%7C47&Model=C20%20Pickup%7C1999&Year=1973%7C1973&ie=UTF8&n=15684181&newVehicle=1&s=automotive&vehicleId=1&vehicleType=automotive
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The 618W is manufactured for Corvettes.
Do the exhaust manifolds route above or below the spark plugs? Does your engine use an individual heat shield wrapping around each spark plug or an open tin roof heat shield for each pair of plugs? Both factors will have an impact on which plug wires the engine can use. Post a pic showing one side of the engine and how the existing plug wires are routed. ACDelco 9608N, I believe routes over the top of the valve covers in applications for which the exhaust manifolds route below the spark plugs.
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The spark plugs are below my exhaust manifold.
Currently, only a few cables (3) sit near a header that are individually heat wrapped.
Attached is a picture of the Passenger Side.
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All of the spark plug boots on the 9608U are 90° whereas the 9608N has a couple of straight boots. Running headers can change the fit requirements, so you will have to choose by trial and error. I suspect 90° spark plug boots will provide the best fit. All of the HEI distributor cap ends are 90°.
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Thank you.
I see the 9608U are 8mm wide. Is this an appropriate width for a spark plug cable in my scenario?
What is the difference of having a wider cable than a thinner one?
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The thicker the insulation the more durable the wire and the greater the dielectric capacity (the lower its susceptibility to insulation breakdown and arc perforation). Too thick and the wires won't fit the wire guides.
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Very interesting. I was unaware of dielectric.
So this to say, the spark wire cable itself has no conductor within it and the electricity travels from the distributor to the spark plug merely by force?
I'll go ahead and grab these guys:
https://www.amazon.com/ACDelco-9608U-Professional-Spark-Plug/dp/B000S2VWGQ
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So this to say, the spark wire cable itself has no conductor within it and the electricity travels from the distributor to the spark plug merely by force?
lol - If this were the case, the wire insulation would have to be two feet thick.
No, there is a conductive core centered within the wires, typically either a carbon impregnated fiberglass or Kevlar cord (factory style wires) or a fine alloy wire filament spiral-wound around a Kevlar core (many higher-performance aftermarket wires). The fiberglass/Kevlar core imparts strength to the core while remaining flexible. "Dielectric" refers to the effectiveness of the insulation or its voltage tolerance.
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When the new wires arrive, be aware that the boots are not the same from end-to-end. They are manufactured from different materials. The spark plug boots are more tolerant of high temperature due to their proximity to the exhaust. Look at them closely and you will see a subtle difference in their shapes.
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Living and learning... Thank you though.
(I'm excited for the Physics classes coming up in the fall. More math in the spring first, Trigonometry starts next week.)
I found this video in my search which led to my question:
https://www.youtube.com/watch?v=-542IYGBbpg&app=desktop
Speaking of which, should I be applying dielectric grease to my new boots when they arrive as shown in that video?
Also, should I be applying anti-seize grease on my new spark plugs?
I'll be sure to examine the boots of the cables when they arrive and/or take pictures if I become confused. Should be here Saturday.
(Cap and Rotor arrived today. 14 hours after I hit the purchase button, they arrived on my doorstep. What a world we live in...)
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Some photos to show the replacement of the rotor and cap; she started right up.
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The things you 'learn' on the Internet.... ::)
Although it is loosely referred to as "grease" because of its consistency, dielectric compound is not grease.
Yes, a dielectric compound is an insulator. Too often, dielectric 'grease' is promoted by countermen as a superior coating for low voltage applications such as the sockets and bases of miniature bulbs and wire connections. The only benefit it provides is that it rejects moisture. But, because it's an insulator, it's a poor choice! Always use an antioxidant paste for electrical connections. Antioxidants reject moisture and dissolved salts, but also help minimize galvanic reactions and sink heat. In a pinch, you can substitute a medium lithium grease.
Yes, a dielectric compound will help seal the boot against the spark plug porcelain and control arcing down the outside of the porcelain to ground.
No, a dielectric compound will not prevent arcing through the boots, but it will improve the service life of the boots by preventing the boots from adhering to the porcelain of the plugs so that the boots aren't strained or torn during subsequent removal.
Yes, use dielectric grease sparingly in the boots at both ends of the wires, but not for the reason given in the video. Too much compound will seal the boot so well that it will prevent the escape of gases that collect inside the boot, causing the boot and wire to literally blow off and separate from the spark plug, resulting in a misfire. Ignore the commentary regarding "no compound" on the terminals, too. Instead, coat the terminals of the spark plug wires at both ends to help control corrosion and erosion. The female terminals of the spark plug wires engage the male terminals of the spark plugs and HEI distributor cap towers with a positive snap and direct metal-to-metal contact, scraping away compound at the points of contact. In addition, put a dab of dielectric compound on the end of the rotor and on each tower terminal inside the cap. Dielectric compound in the arc path burns to a white fluffy ash that is conductive, yet adds a small amount of resistance to help control RFI.
Generally, do not apply anti-seize to spark plug threads in iron heads. Anti-seize introduces a thermal barrier between the spark plug and head, which can lead to an increase in spark plug temperature. Instead, use a few drops of SAE 30 motor oil. The only exception is aluminum heads, with which you can use a sparing amount of copper anti-seize.
The natural sciences can be a lot of fun, not to mention useful on a regular basis. If you're targeting a natural science degree, learn trig well.
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Since you are giving it a tune-up, don't neglect the fuel filter and air filter. ;)
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The air filter is fairly new, but how do I locate/replace the fuel filter?
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The factory fuel filter is located inside the carburetor behind the fuel inlet nut. You will need a 1" angle head open end wrench and 5/8" 6-point flare nut wrench to remove the fuel line and the inlet nut.
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Please excuse my late response, I had two 16 hour days back to back.
Once again, thank you.
The things I learn from you are greatly appreciated. I just spent time familiarizing myself with galvanic corrosion; it's exciting.
So, despite the pros, cons, and common beliefs of dielectric compound being used as a grease, it would be beneficial to use some sparingly on the inside of my boots as a mild lubricant?
Perhaps I'll use a q-tip to carefully do so.
I'll also use it on the terminals as you said, but I would like to ask why?
I think a good question may be, what is RFI?
In regards to my spark plugs.
I have copper spark plugs. So it would be best to coat the threads just a little bit with SAE 30?
My new torque wrench arrived today! So I'll be removing them all and torquing them correctly at 22.5lbs tomorrow.
(All except 1. The spark plug closest to the firewall on the driverside is too close to the header for me to get the spark plug socket on. I had to go underneath so that I could reach between the headers with a vise grip to carefully replace the one there now.)
My cables and new dust cover for my distributor arrive tomorrow.
I'll take care of this and then familiarize myself with the fuel filter.
Thanks again BD!
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RFI = Radio Frequency Interference --- Bookmark Common Automotive (& Shorthand) Acronyms (http://forum.73-87chevytrucks.com/smforum/index.php?topic=32586.0)
A film of dielectric compound coating the spark plug wire terminals helps shield the terminals from ozone and retards corrosion. Don't misconstrue the advice. Applying dielectric compound imparts subtle benefits, the greatest of which is to help prevent the boots from adhering to the plugs. It isn't a necessary step and won't perform miracles.
Use a little motor oil on the spark plug threads. "Copper" spark plugs simply means the conductive cores of the plugs are constructed using a copper alloy, which is an excellent thermal conductor. Copper core plugs effectively provide a broader working heat range.
Once you gain the sense of 22 ft-lbs of torque you can dispense with the torque wrench and tighten the plugs by feel. For spark plugs that are shrouded by headers and have limited access try a close quarters socket (https://www.summitracing.com/parts/sle-30102) (imaged below).
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That Acronym list is excellent. Thank you.
Last night, I removed the distributor cap, put a touch of dielectric compound on the tip of the rotor and tower terminals.
I noticed that the inside of the tower terminals already had a mark on them from the rotor. I was surprised as I only had the engine running for maybe a total of 5 minutes thus far.
I removed all the spark plugs, gapped them to .45, coated the threads with 10/40 and torqued them all to 22.5
All the spark plug cables look great. As you said, there was a difference to the ends.
I didn't notice anything material wise, but DIST was printed on one end only. I connected all these ends to the Distributor cap.
She started up just fine. Very rewarding work.
Only thing now, is some of the spark plug cables are too close to my headers.
Others are resting on the valve covers and they will need to be protected.
The previous owner kinda did a poor job, in which he just wrapped portions of the spark plug cables with heat wrap/tape.
Would you be able to recommend a cleaner look in protecting the spark plug cables? Maybe sleeves would look better?
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Boot protectors and wire looms are something you will need to figure out depending on wire routing and the look you want.
https://www.summitracing.com/search/part-type/spark-plug-boot-protectors?ibanner=SREPD4
and
https://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=chevy%20spark%20plug%20looms
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Maybe something like this?
https://www.summitracing.com/parts/mrg-6326k
Any con's you foresee?
Do you think that material frays when cut?
Perhaps, I could cut each piece to length and harness with a metal zip-tie?
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Either cut it using a hot knife or singe the ends after cutting to control fraying.
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Alright... Back where I started somehow.
After the following:
-New spark plugs gapped at .45
-New spark plug cables, sparingly coated with dielectric compound
-New Rotor and Cap, also sparingly coated with dielectric compound
-New 12gauge power feed wire coming from ckt 3 on the bulkhead to the Tach Terminal on the Distributor cap.
She died on me today running some errands.
I was able to get the truck running after each step listed above, but haven't taken her out until today.
While backing out of a parking spot, she died.
Towed it home and took a reading on the power feed to the distributor which read 12.27volts.
Any idea what to check next?
The truck sounds exactly as it did when it first died on the 19th; it cranks but won't start.
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Padawan, why did you connect the I+ lead to the tach terminal? Move I+ to the BAT terminal of the HEI distributor cap and retry. If it doesn't start, recheck for spark.
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Padawan,
Haha, I needed that laugh right now.
I confused myself, it's been connected to Batt all along.
Currently, there's no help available to crank the engine and check for spark. Hopefully tomorrow.
However, in the interim, I just took the dust cap and cap off to inspect it and the connection is strong and nothing is burnt.
Inspected all of my spark plug cables which are all healthy and also not burnt.
Disconnected the bulkhead to ensure ckt 3 was clean, which it is.
(The wiring on the passenger side needs work, but I'm saving that project for now considering I'm getting 12v at the distributor cap)
Why do you think I would be receiving no spark with all new gear?
I check to see if it runs after each step I take when replacing everything from the spark plugs to power feed.
Today, I drove within 2 miles which included me turning the engine on 4 times and off 3.
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Generally, checking for spark is the first step in diagnosing a no-start condition, then fuel, then compression and engine condition.
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So, there is a spark. It's not bright blue, but orange, and it seemed to be a bit chaotic as to where it was grounding.
Perhaps the gap is too big? The old ones I pulled were .30 and I gapped the new ones at .45
I tried to capture it on video here: https://www.youtube.com/watch?v=ufgR4iEQiSc&feature=youtu.be
Now here's the kicker...
I figure I'd try again after reinstalling the spark plug and to my surprise, she starts.
It was a little rough so I kept my foot lightly on the gas before she died again about 45 seconds later.
I was starting to think it might be the ignition coil until I saw the spark, now I'm thinking it's fuel again.
My original thought was that I had destroyed my fuel pump by running out of gas on the 16th.
(I broke down on the 19th because of the poor connection of my I+ feed to my Distributor)
The fuel gauge has been broken since I bought the truck in Dec of 14'. Excuses aside; I'm certainly guilty of having had run out of fuel 4 or 5 times since then.
However, I can see fuel when I prime the carb.
You can also smell fuel under the hood and the carb is wet after priming.
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That was a great video of the hose and frame.... :P
Healthy HEI has no struggle arcing a 0.045" gap (a few HEI equipped engines use spark plug gaps of 0.080").
No need to remove a spark plug from the engine to check for spark. Reiterating from earlier in the thread, remove a wire from a spark plug and slip the boot up the wire until the terminal is exposed then hold the terminal about 3/4" away from the frame or exhaust manifold, etc. If you would rather use a tool to make testing easier (and less shocking ;D), pick up an HEI spark tester like the one in the image. Don't substitute. The pictured tool has the correct gap to test HEI and most other electronic ignition systems. The spark plug wire connects to the tool without having to move the boot, then the tool clips to a bare metal ground. HEI should have no trouble jumping the prescribed test gap.
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38405;image)
Crank the engine and post another (better) video. If the engine starts and runs, run it until it quits then pull a plug wire off and recheck for spark. You need to verify a strong and consistent spark before moving on to a/g else. Don't get ahead of yourself. Work methodically and patiently.
As long as there is sufficient fuel in the vehicle and the fuel isn't contaminated with water or other liquids, don't be concerned with fuel at the moment.
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...I know... I was terrified. My neighbor checked the spark last time, and I didn't see how he did it as I was inside turning the key.
I tend to exercise extreme caution when dealing with new things I don't yet fully understand; including electricity.
(You should have seen me when I was learning how to ride 8 years ago, I would hug that clutch...)
One worry I had was not knowing what to expect from the arc and not wanting it to arc to my phone.
I was also weary of cranking the engine for too long as it sounds terrible.
Is it okay to try to crank for 20 seconds when checking for spark?
I'll tape my phone with some gaffers cloth tape to a nearby hose for a better image.
I've attached an image with the boot off; do you think this would be an appropriate approach for testing for spark? (Again, learning curve with dumb questions. Your patience is more than appreciated)
I could try again tonight, but there is some condensation out there.
Would it be best to wait till midday tomorrow when it's dry?
There's now about 11 gallons in the tank.
It did however cross my mind that the fuel could have been compromised as I live in East Hollywood with a growing reputation of nonsense amongst vagrants and/or gangs.
My property is not gated, but I do have the luxury of a driveway where the truck can not be seen from the street.
I'd like to put that theory to bed as I believe someone would just steal the truck opposed to sabotage it. So I'd like to believe there is nothing but 87 octane in my tank.
The downfalls of living in an overpopulated city for work... I've been rethinking this for sometime now as well.
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Don't be concerned about condensate. Holding the wire as imaged is perfect. Create a 5/8" - 3/4" gap between the wire and ground. The maximum limit of the arc should be about 1" or so. Keep in mind that testing for spark, while the no-start symptom is active, is important.
Twenty seconds of cranking is a long time. You should be able to verify a consistent spark in one-third of that time. If you must crank the engine for 20-30 seconds, let it rest for at least a minute before cranking again to allow the starter to cool.
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and you mention the sound of the engine. what does it sound like? it shouldnt sound terrible
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Hi Spool:
You know, if you have replaced your coil, cap, rotor, spark plugs, plug wires at this point in time, the only electrical things to test before your go to fuel checks would be the module in the distributor base and the pick up coil in the distributor base below the module. The module is easy to remove and I believe it can be tested by car parts stores like Autozone. The pick-up coils can be tested in the truck with an ohm meter but their failure mode can be intermittent where they are tough to gauge whether they are bad or not...I will defer to BD to advise how you can test the pick-up coil. I have a oem HEI in my 76 and went through similar failure modes as you have only to finally come down to the pick-up coil replacement after replacing all the other electrical items and solving the intermittent stalling problem.
Regards,
Henry
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Distributor componets test (http://forum.73-87chevytrucks.com/smforum/index.php?topic=29995.0)
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Thanks everyone.
I had no luck on getting a spark with the boot off as seen in this video:
https://www.youtube.com/watch?v=WjaJ3MQLQso&feature=youtu.be
Nor did I have any luck with a surprise start up as I did last time, as seen in this video:
https://www.youtube.com/watch?v=Nd1X4P3rnEw&feature=youtu.be
(Irish, I should of been more descriptive with terrible. But the engine sounds like it's in distress, so for this most recent test I only cranked the engine for about 6 seconds)
I have not replaced the coil at this point, but I do have new cap, rotor, spark plugs, spark plugs cables and a new 12guage wire from ckt 3 to the distributor.
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(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38312;image)
Referring to this image ^^^^^ notice the red and yellow coil wires. The red wire is coil positive and is the BAT terminal of the distributor cap (ignition power from circuit #3). The yellow wire is coil negative and is the TACH terminal in the distributor cap. Using signal input from the distributor Pick-Up Coil (PUC), the Ignition Control Module (ICM) controls primary current through the ignition coil by alternately completing and breaking the ground connection (yellow wire) to the coil. When the ignition is operating properly, the TACH terminal of the distributor cap (coil negative) switches ON and OFF (digitally) at a frequency that is directly associated with engine RPM. Consequently, connecting a test light between ground and the TACH terminal of the distributor with the engine running will illuminate the test light with a luminosity directly related to engine RPM and the duty-cycle of the test light - the greater the RPM, the brighter the test light. Do you get the idea?
With the preceding concept in mind, disconnect the I+ lead from the distributor BAT terminal and the short pink/black/brown three-wire harness (aka, terminal block) from the distributor cap. Construct three temporary jumper wires that will allow you to reconnect the terminal block as follows: black to a verified ground; pink to either I+ or B+; leave brown disconnected. Now, connect an incandescent test light between the pink wire and the brown wire (electrically, you are removing the ignition coil from the circuit and substituting the test light in place of the ignition coil). Does the test light pulse On and OFF while cranking the engine?
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Hey Spool. I'm new to the community. I read you post about your truck dying. I was having the same problem. I have an 85 c20 with a 350. I changed all the electrical parts and it would still die going down the road. I started looking at the fuel system and found the valve that switches between the left and right side tanks had a crack on the main outlet stem going to the carb. The plastic was brittle and broke off while I was checking the hoses attached to it. After it broke off, you could see the old break in the plastic. I guess it was sucking air through it. Not sure about you truck model but my truck dying was a fuel problem.
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if it has dual tanks it could be the switch itself or the valve but i think his is only single tank but he never does verify this. im kind of assuming just due to him only talking about the gas in the tank and not tanks
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Thanks Uncle G.
I wish I had two tanks, but someone had removed the passenger side one at one point.
BD,
I went ahead with the test but with no luck.
I've attached a picture of my configuration.
-Black to Ground
-Pink to I+
-Test light clipped to I+ with it's ground clip attached to brown.
Is this correct?
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Assuming you verified the ground point on the firewall and the I+ source with the test light before performing the check, then either the ICM or the PUC or the terminal block failed. Time for a decision.... The ICM is easily replaced by removing the distributor cap and a couple of 1/4" hex-head retaining screws. Replacing the PUC requires removal of the distributor from the engine followed by removal of the distributor gear and shaft. The PUC is retained by a snap-ring. 1) you can remove the ICM and have it tested at a local parts house or shop that has the appropriate equipment, 2) You can hope for the best and replace the ICM to see if that solves the no-start condition (if it doesn't, then you'd be faced with replacing the PUC), 3) you can replace the complete distributor with a salvage yard take-out, 4) you can replace the complete distributor with a reman, or 5) you can replace the complete distributor with a new component off of E-bay (https://www.ebay.com/itm/Fits-Chevy-V8-HEI-Distributor-w-65K-Coil-7500RPM-350-454-SBC-BBC-premium-quality/401451921098?hash=item5d78662eca:g:kjMAAOSwsFpaF4jQ&vxp=mtr), for example, with new PUC, ICM, terminal block, coil, cap, rotor, vacuum advance can, and bearings for about the same price as an ICM and PUC combined.
Depending on your decision, removing the distributor will require a distributor wrench and a timing light. Replacing the PUC will require, in addition, a 1/8" pin punch, hammer, rib-joint pliers or a vise, and a small pick for the PUC snap ring. You will also need some aerosol cleaner and LPS 3 lubricant.
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Well, well, well.
My first real roadblock.
Budget wise, I think replacing the coil would be best while crossing my fingers it solves the issue.
Do you think this would suffice?
https://www.amazon.com/ACDelco-D504A-Professional-Ignition-Coil/dp/B000BYB1PS/ref=sr_1_30?s=automotive&ie=UTF8&qid=1518062014&sr=1-30&keywords=acdelco+ignition+coil
If I have to replace the PUC, I'm not currently able to afford the time of learning the process or tools, which would force me to take her into a shop.
Hopefully, knowing exactly what I needed done to the truck, I could get a fair price on labor.
What would you have recommended if the test light did illuminate?
Newbie question #32: How do I verify ground other than a clean metal surface?
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Also, why do you think I would receive spark with the spark plug, but no spark with just the spark plug cable terminal?
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Carefully reread my two prior posts and click the links below as you come across the acronyms/words.
ICM (https://www.amazon.com/ACDelco-D1906-Professional-Ignition-Control/dp/B0013FZX5S/ref=pd_bxgy_263_2?_encoding=UTF8&pd_rd_i=B0013FZX5S&pd_rd_r=R5S05VMZ23DY3NVJ9HF8&pd_rd_w=bFqC9&pd_rd_wg=ICHQD&psc=1&refRID=R5S05VMZ23DY3NVJ9HF8)
PUC (https://www.amazon.com/ACDelco-D1907X-Professional-Ignition-Distributor/dp/B0016HPUY2/ref=sr_1_1?s=automotive&ie=UTF8&qid=1518065673&sr=1-1&keywords=acdelco+d1907x)
terminal block (https://www.amazon.com/ACDelco-D221-Professional-Antenna-Capacitor/dp/B000IXUP36/ref=sr_1_1?s=automotive&ie=UTF8&qid=1518065762&sr=1-1&keywords=acdelco+d221)
ignition coil (https://www.amazon.com/ACDelco-D504A-Professional-Ignition-Coil/dp/B000BYB1PS/ref=sr_1_30?s=automotive&ie=UTF8&qid=1518062014&sr=1-30&keywords=acdelco+ignition+coil)
That out of the way, if you are going to gamble, replace the ICM. Describing HEI function in different terms, the ICM is a switch that turns the ignition coil On and Off. The ICM receives its "instructions" to switch the coil On and Off from the PUC. So, the PUC controls the ICM and the ICM does the work of actually controlling power through the ignition coil. The terminal block just connects the pieces together. Incidentally, there are two styles of terminal block (early and late). The one linked above should service both styles.
Spark is actually generated when power through the ignition coil is interrupted by the ICM. Per your test, the ICM/PUC are not switching power to the ignition coil, hence, it cannot generate a spark.
IF the test light had illuminated and pulsed during crank, I would have recommended replacing the ignition coil.
Question #32 (Please tell me you aren't actually keeping track. ???) - With the test light clipped to a known power source, probe the ground point to ensure the test light illuminates. If it does then both the power source and the grounding point are valid for performing tests. 8)
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Hi Spool:
Sounds like your last electrical test is the coil...hopefully it is the bad actor. If not, then it is on to looking at the ICM, term block, and PUC. I agree with BD, if it is one of these three, just replace the entire distributor with all three included and save yourself a lot of time and annoyance and a little bit of money...even if the PUC or ICM are individually diagnosed bad and replaced, the other one will shortly go bad as well....and then you have to take it all apart again. You can get aftermarket HEIs on line as cheap as $60 and then those guys at Classic Industries down the road from you have a good selection from $60 to $150. From previous replies it sounds as if you dont have the tools to change out the distributor. It is really not that hard if you have a Chevy V8 distributor wrench, timing light, white-out, and a little more time. I am sure you have those "mobile mechanics" in LA who can drive over to your place and change it out for you if you buy the distributor yourself. They typically are cheaper than a shop and changing out a old fashioned V8 Chevy distributor is so basic I would trust them to do it....watching them, of course.
After all this, if you still have stalling problems at least you know it is not the electrical system and then it is the carb or fuel pump giving the problems. From my experience of owning my 76 C20 for 35 years, when the ignition parts start to give problems, the carb is usually overdue for a cleaning or rebuild as well.
Regards,
Henry
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That out of the way, if you are going to gamble, replace the ICM. Describing HEI function in different terms, the ICM is a switch that turns the ignition coil On and Off. The ICM receives its "instructions" to switch the coil On and Off from the PUC. So, the PUC controls the ICM and the ICM does the work of actually controlling power through the ignition coil. The terminal block just connects the pieces together. Incidentally, there are two styles of terminal block (early and late). The one linked above should service both styles.
Thank you for this. I now have a visual for how it works.
Lastly, if I could confirm that visual while including the I+ to the distributor?
Does the I+ power the PUC, which instructs the ICM which in turn controls the Ignition coil, or does the I+ power both the PUC and the ICM simultaneously from the Batt Terminal?
As much as I enjoy and want to change the ICM, PUC and Coil myself it doesn't seem like the wisest thing to do at this point considering the cost of them independently compared to a whole distributor as you both noted.
What do you guys think of combining the two ideas?
What if I were able to pick up a whole new distributor and then use the ICM, PUC and Coil from that to make my replacements?
With that, hopefully she works, and if not, then I can call a mobile mechanic to come and swap out the whole Distributor itself.
I don't have a timing light and at this point in time I would certainly feel more comfortable having a professional get the job done efficiently.
(I've been giving UBER far too much business these past 3 weeks)
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I+ powers the ignition coil and the ICM. The PUC is not powered by any external source. It is an AC generator that provides a trigger voltage to the ICM.
If you are going to procure a new distributor, replace the complete distributor. Actually, replacing the complete distributor is less work for close to the same price as replacing just the PUC. Why buy a new car just to use its tires on an old car?
You may be able to rent a distributor wrench and timing light at low cost from a local parts house.
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At this point, I'm looking at it from an economical stance where as, it's cheaper to buy a whole new distributor than a ICM, PUC, Coil, and/or Terminal Block individually.
With that, what's the best Distributor for my buck?
Would this suffice? I'm not really sure what to look for considering my learning curve.
https://www.amazon.com/dp/B00VLEZRAC/ref=sspa_dk_detail_6?psc=1&pd_rd_i=B00VLEZRAC&pd_rd_wg=mjdqp&pd_rd_r=D61GF74KYP3EG7JWT1D7&pd_rd_w=SICHN
Now the second step is getting it in my truck.
The primary objective for me, with my love of learning and hobbies aside, is to get my truck running as it's starting to hurt my pocket.
With that objective, is it wisest to:
A: Spend a day replacing the ICM, PUC, Coil and Terminal Block in efforts of getting her to run.
B: Find a House-Call mechanic for what I'd hope to be 3 hours of work at $100/hr?
C: Take the time to locate a distributor wrench and timing light to learn and execute the procedure. (This one frightens me a bit, because if I mess it up, I'm just adding more time to the process.)
Let's say I go A, as I feel like that will save me the most money to get my truck running.
What am I losing by not having the entire Distributor replaced?
Or rather, what other part of the distributor could I expect to fail on me over time?
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Hi Spool:
I did not see on the thread where you confirmed testing of the coil showed it was good or bad...maybe I missed that.
If the coil tests good, then I would assume either the ICM, or PUC can be bad and then the most economical and time saving action would be to buy a complete distributor and replace the old one with all the new parts already installed.
The one you have found on Amazon is probably fine...I helped a friend replace his with a similar El Cheapo on Ebay like you have found, and it has been working fine for years. I have bought a $125 one which is Proform brand from Classic Ind and it has been working fine for a couple of years...I have not heard of quality problems with the cheap ones you find on-line.
If you replace the entire distributor the additional failure parts you are getting is: coil, vacuum advance diaphragm. You are also getting a new gear and shaft bearings although these are not common failure items until the distibutor gets over 200K.
Concerning the options you have outlined, if you ask me I would say option A is actually the most expensive and labor intensive. I would say that all three options are going to tie you up for a planned day anyway. Considering the troubleshooting work and skills you have demonstrated so far, I think you have the ability to change out the distributor yourself successfully...I think you have greater chance of messing something up if you start playing around with the PUC....I think the distributor has to be removed anyway to change it out easily. All of us on the forum can guide you through the steps to change it out and if you follow the steps and take careful notes of positions of things and be patient you can do it. The dist wrench and timing light are not that expensive.
Tools:
1. cheapest timing light at parts store
2. Chevy V8 distributor wrench at parts store ( I personally like the 2-piece design by Great Neck)
3. white-out or permanent fine felt pen (white or silver) from Office Depot
4. small packet of distributor gear grease at parts store
5. long flat blade screwdriver
6. pad and pencil for notes
7. assistant to help you set the timing...someone needs to hold the timing light and eyeball the timing marks on the crank pulley while you turn and tighten the distributor when engine is idling....about 30 minutes of his or her time. You can do it yourself but it takes a long time with just one person....about 1 to 2 hours.
8. rags and solvent to clean away grease and gunk on timing marks and distributor hole.
Regards,
Henry
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Spool, since your living on a student's budget, perform a few checks of the PUC with the distributor still in the engine. Let's see if we can determine whether there is a hard failure of the PUC before making a final decision on repair strategy. Disconnect the power wire from the distributor and remove the distributor cap and rotor to improve access to the PUC. Use the link provided earlier by Irish_Alley, Distributor components test (http://forum.73-87chevytrucks.com/smforum/index.php?topic=29995.msg251277#msg251277), and scroll down to Pick-Up Coil. Perform the resistance measurements as described. When tugging on the leads, don't pull too hard. The idea is to determine whether the wires are broken inside the insulation, not to break them by pulling.
If the PUC passes the resistance tests, set your meter to AC volts and select the 2-volt or lower scale. With the PUC still disconnected from the ICM, connect your meter's leads to the two wires of the PUC (polarity is unimportant). Make sure the meter leads are out of the way of the rotor support and shaft and not grounded to the distributor housing. Have an assistant crank the engine while you monitor the meter. What is the millivolt reading?
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Thanks Henry.
You certainly settled my nerves with the timing light.
An employer of mine, owner of 59' Ford F150, may be able to assist me in the timing light procedure. I've already reached out to him.
I haven't tested the Coil yet.
Irish, had posted instructions to do so,
http://forum.73-87chevytrucks.com/smforum/index.php?topic=29995.0
I didn't quite understand the process but believe mine is a Married Ignition Coil and upon visual inspection it doesn't show any signs of corrosion, cracks or oil leakage.
BD, had helped rewire the ignition around the coil using jumper leads and a test light which showed either the PUC, ICM, or Terminal Block was bad as I couldn't get the test light to illuminate; which is what led to the discussion of getting a new distributor.
As per the purchasing a Distributor, I've selected a different one just now for shipping concerns.
This one could arrive this weekend. Would this suffice? Correct voltage, size, etc?
https://www.amazon.com/dp/B00VLF11CO/ref=sspa_dk_detail_3?psc=1&pd_rd_i=B00VLF11CO&pd_rd_wg=PhoL3&pd_rd_r=407YA4P5X7Z5WYFA9X33&pd_rd_w=UZDdC
BD, per your last post, in testing the PUC, if the PUC fails, what would you recommend?
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Either of the distributors you linked should suffice. If the PUC fails its tests, replace the distributor. If it passes, you have the option of replacing the ICM, which may resolve the issue without any guarantees.
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Thanks BD.
I'm gonna go ahead and order the second distributor I shared.
I can't thank you enough for helping me, but I'm gonna bypass the PUC test to just get a guarantee in place to get my wheels working.
Asides from school, I work production and post production. Post production, editing, is done from home.
However, my production work is hurting from not having reliable transportation as some jobs are 30+ miles away.
With that, I'll order the distributor to fix/rule out ignition.
I'll see if I can grab assistance from the employer I mentioned as for the timing and experience.
Henry offered a helpful list on needed tools.
I began pricing timing lights, but it seems a sufficient one is $100. Is this about right?
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They vary in price over a broad range. A basic timing light is not horribly expensive...
Harbor Freight (https://www.harborfreight.com/timing-light-with-advance-40963.html)
Innova (https://www.autozone.com/test-scan-and-specialty-tools/timing-light/innova-digital-timing-light/108151_0_0)
Sears Craftsman (http://www.sears.com/craftsman-advanced-timing-light/p-00914065000P)
Generally, the higher the cost, the more durable and reliable. Yet, most should work fine and provide decent service if you take care of them.
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Hi Spool:
The test for the coil that BD sent you is to be done with the cap of the distributor off with the coil still mounted in the cap. Position the cap upside down so you can see the spade terminals in the cap projected shroud. Test one is to check the resistance between the outermost two terminals which should be the same ones shown on BDs illustration. Resistance should be very close to 0 (on 1X scale) or as he has specified. If it doesnt pass this test, the coil is bad. If it passes this test, a second test must be performed: connect the ohm meter leads between the TACH terminal and the center terminal in the cap and take note of the reading on the highest scale.Take both ohm meter leads off. Then connect both ohm meter leads on the center terminal (of the group of 3 spade terminals) and the center terminal in the cap and take note of the reading. If both readings are infinite resistance, the coil is bad. This should be the second test in BDs illustration. If either reading is between 6K to 30K ohms, the coil is OK and the problem may be somewhere else like the ICM or PUC.
The distributor looks fine to me and I would expect when you get it the instructions may discuss the setting for the adjustable vac advance...hopefully it will be at a default setting that you dont have to adjust.
$100 for a timing light is a lot more than I would pay as a shade tree mechanic. I have a cheapie with a positive and negative lead and a spark plug wire clamp. I would also make sure it has a Xenon lamp as you need the brightness...nothing else required. I use mine about once every 5 years and so it doesnt get a lot of use and doesnt need to be high quality. Maybe the guy that will help you can loan you his...?
Let us know when the installation of the new distributor is imminent and we can send you detailed instructions.
Regards,
Henry
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Thank you, Henry.
However, with testing aside, I purchased the distributor that I shared earlier which arrived on Sunday and looks sharp.
I'm back from my 4 day hiatus of work deadlines and week 1 of school.
In between that, I've been attempting to familiarize myself with the process of replacing the distributor and the process of timing; all of which I'll take at internet face-value as I would much rather prefer to ask the forum, but it did shed some of the green off from behind my ears I suppose.
However, I do think this video is worth mentioning as it was one of the most straight-forward videos I was able to come across.
https://www.youtube.com/watch?v=Wwp9rtTPPJc&feature=youtu.be
Think I can take his advice?
Other videos and websites weren't as informative but they did point to the process of finding Top Dead Center, aligning the rotor to 1, and some vocabulary.
I've attached some photos.
I like the top cap of the distributor.
Other two photos are of my timing tab & distributor bolt which are both very dirty.
My original help has been waiting for his first born; I'll have to grab a nearby neighbor or co-worker.
(Friends don't come as good as they did when I was 17.)
I went ahead and ordered the Innova Timing light BD shared, along with distributor wrench (1/2'' & 9/16'')
Which only really leaves the distributor grease for my purchase order; is it specific like this:
https://www.amazon.com/Super-Lube-Distributor-Grease-Gram/dp/B01JKGVEHW/ref=sr_1_1?ie=UTF8&qid=1518589732&sr=8-1&keywords=distributor+grease
I'll most likely go to AutoZone for this, but wanted to clarify if it was specific to the distributor.
Once again and as always, thank you.
I hope to do this project on Thursday/Friday or this weekend.
With that, what's the first step?
Other than removing the distributor, I'd assume I would need distributor grease to place the new one and a process of finding TDC?
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Hi Spool:
The grease you found on Amazon is really for applying on the cam inside the distributor of old points type of distributors. The grease (or heavy oil) you need for the distributor helical gear is the same grease they use on camshafts or engine assembly grease. Tell the guys at Autozone you want the "cam and lifter lubricant" which they should sell in 1 fluid oz packages or smaller. I remember Comp Cams used to be a brand that sold this. If they dont have it, ask for "motor assembly grease" which they may sell in 10 fluid oz tubes. I remember Lubriplate used to be a brand that sold this.
As far as the video is concerned, it is all correct but I quit watching it because the guy was just talking about setting the timing and not the actual replacement of the distributor which I believe is what is critical. If you believe your timing is already correct or close enough for the engine to run, you do not need to find TDC on your engine when you swap out your distributor if you follow the procedure I have outlined below. Read this procedure a day or two before you do it and go to the store. If you have any questions feel free to ask. Since it is long, I have also attached it as a Word file to print out.
Replacing Distributor on small block Chevy V8
1. Clean of the grease and grime from the timing pointer on the engine block. You need to be able to read the numbers and the hash marks next to the numbers. Clean off the grease and grime from the groove mark on the crankshaft flywheel…this is a slot that needs to be clean so you can paint a white or silver line inside the groove. Feel around the entire diameter of the flywheel as there may be a second groove 180 degrees out. Paint a line in both grooves to be sure you have the right groove marked.
2. If the engine will start and run, do a timing check to see what the timing is before the old distributor is removed…if it is hard to start or will not start reliably, skip this step.
3. Once the engine is cool, mark all the spark plug wires as to which cylinder they plug into. If you have the original intake manifold, you should see the cylinder numbers cast into the manifold. You should have a pad and paper so make a diagram of the engine and where the cylinders are so you will know how to replace the wires. Use the silver or white pen to mark them all…you can make the marks on the distributor cap.
4. Pull all the spark plug wires off the plugs and release the wires from any wire clips and making notes of where the clips mount and which wire goes to which clip.
5. Using a long phillips or flat blade screwdriver, push and turn the levers that hold the distributor cap on the distributor and remove it with all the wires attached. The rear lever is hard to get to so you will have to lay on the engine and remove this one by feel. You can look at your new distributor and see how they work. Take a note on your pad about which cylinder the rotor is pointing to (or close to pointing to).
6. Clean off all the grease and grime at the base of the distributor and intake manifold where it mounts. Clean it so that you can access the distributor bolt and so that grit and grime will not fall into the hole once the distributor is removed. It also needs to be clean enough such that you can make marks on the distributor base and intake with your marking pen or white-out.
7. Before removal of the old distributor, mark where the base of the distributor is with respect to (wrt) the intake manifold…you can make a line across both parts on the drivers side opposite the distributor bolt. Make note of where the vacuum advance diaphragm port is located with some other feature on the engine. Also, note where the distributor rotor is pointing…you want to make a mark on the engine somewhere to show this…this is very important…I call this the “installed position”.
8. Pull the vacuum hose off the old distributor vacuum diaphragm and plug the hose. I usually use a golf tee to plug it.
9. Removal of old distributor: the distributor is engaged to the camshaft with a helical gear…so as you pull the distributor out, you will see the rotor turn a bit before the gears are disengaged. You will want to make a mark on the engine where the rotor stops turning when pulling it out…I call this the “removed position”. Also, the bottom of the helical gear on the distributor has a blade that engages with the oil pump driveshaft below the camshaft gear in the engine that you need to be aware of…when you install the new distributor the engagement of this blade and slot in the driveshaft must be made or the distributor will not seat down on the intake manifold. OK, go ahead and remove the distributor bolt and clamp and clean them from grease and grime and set them aside. Pull the distributor out…it may take a little bit of wiggling but once it starts to come out make note of the rotor position of where it has turned to in order to get it disengaged from the cam gear. You can go up and down a few times to see how it rotates…this is the same rotation your new distributor will have to make when installing. Once the distributor is out of the engine, you do not want to crank, start, or rotate the engine for any reason…doing this will lose the orientation of the distributor wrt the crank firing and make it very difficult to time the engine.
10. Take the cap off your new distributor and using the pen mark all the cylinders as on your old distributor cap. Transcribe the mark on the base of the old distributor to the same place on the new distributor. Transfer all the old spark plug wires to the new cap and set the assembly aside for now.
11. Take your old distributor and new distributor and holding them in the same orientation of rotor wrt body of distibutor, flip them upside down and make note of the orientation of the oil pump blade in the helical gear in both…they most likely will be of different orientation…if they are of different orientation, you will need to be prepared to use a long flat blade screwdriver to rotate the oil pump driveshaft by a certain amount to make sure it engages properly….this is in the next step.
12. Install the gasket on the new distributor driveshaft…you can use some scotch tape to temporarily hold it in place on the distributor mating surface. There is not any sealant or grease that goes on the distributor to intake manifold mating surfaces…it is a dry fit with this gasket. Apply some of the camshaft gear or engine building lube to the helical gear of the distributor. Before installation, hold the distributor above the hole and rotate the rotor to the final engaged position….then look under the distributor helical gear and see where the oil pump blade is oriented. Then get a flashlight and look down the distributor hole and see where the oil pump driveshaft slot is located…if it is not oriented such that it will engage with the distributor gear blade, then you must use a long flat blade screwdriver to rotate the oil pump driveshaft to the correct position. You must be careful during this operation so as not to pull the oil pump driveshaft out of the oil pump…just turn it carefully and do not attempt to pull it up or out. A serious problem can occur if you pull the shaft out and drop it into the engine because it cannot be retrieved without removing the oil pan from the engine. OK, once you have the oil pump shaft oriented with the distributor gear blade, go ahead and start to install the distributor with the mark on the base of the distributor in alignment with the mark on the intake manifold it is supposed to line up with. Note that the vacuum advance diaphragm port should be fairly close to the orientation as the old one. As you lower it, hold the rotor in the removal position as noted earlier such that when the gears engage, the rotor will turn to approximately the same position as the old rotor in installed position. You probably will have to spend a few minutes gently jiggling it all around a bit to get everything to line up. You may have to go in and out a few times…be patient. When it finally goes down into place, look down at where the distributor base seats to the intake manifold…if there is a small air gap, that means the oil pump driveshaft slot has not engaged the distributor gear blade. You must pull the distributor back out and slightly rotate the oil pump driveshaft one direction or the other for engagement and then try installing the distributor again. Once the distributor is properly seated and the marks on the distributor base and intake manifold are lined up, the rotor should be pointing approximately in the same position as the old one…if it is way off (say 45 degrees) that means you are off one gear tooth on the helical gears. Remember, you marked what cylinder the old rotor was pointing to, and you can take your old cap and place it on the new distributor to make sure it is close to the same cylinder. Pull the distributor back out and rotate the rotor a little further to one direction or the other in the “removed position” and re-install the distributor as before. Once you are satisfied that the distributor is oriented correctly, pull it back out just a bit to removed the tape on the gasket and then reseat the distributor and install the distributor bolt and clamp. Look carefully to make sure the clamp actually engages the flange on the distributor base as the clamp is slotted and you can tighten it without actually engaging the distributor flange. Tighten just snug for now.
13. Install your new distributor cap (notice it is keyed and will only seat in one position) and wires onto the engine. Engage the distributor cap clamps and route the wires and plug wires into the spark plugs.
14. Timing the engine: Climb on the engine and loosen the distributor bolt just enough such that the distributor can be rotated by hand but is not just loose. Leave the vacuum diaphragm on the distributor unplugged, but verify the hose that goes to it from the carburetor is still plugged. Hook up your timing light per the instructions that came with the light. On old fashioned timing lights, the positive and negative connections simply go to the appropriate battery terminals and the spark plug wire clamp goes loosely over cylinder #1 spark plug wire. At this point you need an assistant to operate the timing light while you rotate the distributor as the engine is idling. You all need to be careful during this operation as the timing light can get smacked by the fan or the wires from the timing light can get snagged in the belts…you need to be careful how you have routed all the wires of the timing light on the engine and the operator of the timing light needs to be careful he does not get his hands or timing light hit by the fan when trying to look at the timing marks. Also, the guy turning the distributor needs to be careful he does not burn himself on any hot engine parts like the pass side exhaust manifold or radiator water lines. I usually have stable boxes to stand on for both people so that they can lean into the engine without having to place hands on the engine to support their weight during this adjustment…all for safety. OK, now set the parking brake and start the engine and leave the transmission in park. Once the engine has started and is idling, one person should turn on the timing light and see where the timing is on the engine. The other person should then slowly rotate the distributor one direction or the other and ask the timing person what is the response on the timing marks. The timing on my 76 truck is 8 degrees before top dead center (BTDC). If you still have the original air cleaner cover to your truck there should be a decal on it with your timing specs. If not, 8-10 degrees BTDC should be a good starting point for the engine to run properly…you can always reset it later when adjusting the carburetor idle. Once the timing pointer is at this setting, tighten down the distributor bolt and verify the timing has not changed. If it changes, loosen the distributor and repeat the process of setting it and tightening the distributor bolt. Once the timing is set and the distributor bolt is tightened, you are done and turn the engine off.
15. Reconnect the vacuum line to the distributor advance diaphragm. Disconnect the timing light and remove all blankets, rags, and tools from the engine bay and take the truck for a test drive. After the engine has cooled down, check the tightness of the distributor bolt (it has to be tight).
Regards,
Henry
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Thanks Henry,
I have a handful of questions to start after reading the instructions.
I think I may be able to get to cleaning the necessary spots this afternoon or tonight.
-What would be the best way to clean my timing pointer and crank shaft wheel?
Could I use a wire brush with carb cleaner or grease removal?
(The grease removal product enforces the importance of rinsing the area with water when done; I'm not too crazy about introducing water around the engine. Any tips?)
-When removing my plug cables but keeping them on the distributor, I'll go about labeling them based on their cylinder numbers.
Is the picture attached the correct cylinder order for the block and distributor cap?
(Source for cylinder numbers: http://www.classiccarauto.com/impala/how_to/firing_order.shtml)
-To clarify the gasket aspect in step 12; I'll use the same cam and lift lubricant for the helical gear on the distributor around the gasket once it's aligned and seated?
-When adjusting the oil pump blade in the distributor, will I be adjusting anything else that is in unison with it?
If I understand correctly, the rotor moves with the helical gear, but the oil pump blade is independent of any other moving parts on the distributor?
-In regards to cleaning around the distributor prior to removal, would I also be able to use the products in the photos attached with a wire brush? Any tips or other products that would work well or better?
Thank you.
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Use either one of the products you pictured to clean the timing plate and around the base of the distributor. Use a small stiff bristle brush and scraper if needed to remove stubborn caking. No need for concern, hosing off the loose residue left by the motor shampoo. Just don't direct a stream of water into the distributor or carburetor.
If you have a smartphone, snap plenty of pictures before taking anything apart, so you have references during reassembly.
The process of changing out a distributor sounds more complicated than it is in practice. So relax and be methodical adhering closely to Henry's write-up.
Referring to Henry's write up, since you have never stabbed a distributor into an engine I recommend rotating the engine to top dead center compression (TDCC) on cylinder #1 and setting the timing mark on the balancer to 0° before loosening the distributor clamp. This ensures that you begin the job at a known starting point in case of difficulty. To find TDCC, rotate the engine until the distributor rotor points to the #1 cylinder spark plug wire then align the timing marks to 0°.
An alternative to completely removing the distributor cap and all of the spark plug wires is to just lay the old cap forward with all of the wires still attached at both ends. Then transfer the wires to the new cap once the new distributor is installed in the engine, one wire at a time.
The oil pump driveshaft is locked onto the oil pump via a stiff nylon collar. The likelihood of it pulling loose and dropping into the oil pan while removing the distributor or turning the oil pump driveshaft with a screwdriver is very low.
The distributor gasket should be installed dry, without any sealer. However, lubricant won't harm the gasket or defeat its sealing function.
The engine firing order is 1-8-4-3-6-5-7-2 and is accurately diagrammed in the image you posted.
Lubricate the thrust bearing between the distributor gear and the base of the shaft housing with a few drops of engine oil before stabbing the distributor.
The oil pump driveshaft simply needs to be aligned with the drive key up inside the distributor gear at the base of the distributor shaft. If you are lucky the new distributor will drop into place without having to turn the driveshaft. Otherwise, the driveshaft may need to be rotated ever so slightly to engage the distributor. The distributor should drop into place with little effort once the oil pump driveshaft and distributor shaft are correctly aligned and engaged. Make sure the collar of the distributor shaft is seated against the intake manifold before sliding the distributor clamp into place around the collar. Under no circumstances use the clamp and bolt to force the distributor to seat against the manifold! After the distributor is seated and the clamp is in place, tighten the bolt sufficiently that the distributor will still rotate with light-to-moderate effort. This will allow you to set and retain the timing until the bolt is fully tightened after adjustment.
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Thanks BD,
I returned from AutoZone with no luck on acquiring Cam & Lift Lube or Engine Assembly Grease; they suggested Home Depot.
Would this suffice?
https://www.amazon.com/Permatex-81950-Ultra-Engine-Assembly/dp/B000HBNVSK
I'm hoping I can get to at least cleaning the the timing tab and around the distributor tonight.
With the current distributor in-place, it would be safe to rinse the area directly with a garden hose? (I'm just skeptical, please excuse my need for double clarification)
After cleaning, my next step is finding TDCC on cylinder 1.
How do I rotate the engine?
Clockwise with a wrench or ratchet from the center of my flywheel? If so, do you happen to know the size of the nut?
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Hi Spool:
I did leave out one electrical connection that in the step by step process. In step 4, add:
-Disconnect two wire connector plugging into bottom of distributor cap on drivers side of distributor cap.
In step 12, add:
-Connect two wire connector plugging into bottom of distributor cap on drivers side of distributor cap.
I concur with everything BD said.
OK, the assembly lube for the distributor helical gear is not a big deal...you can coat it with 10W-30 engine oil instead.
You can use the cleaners discussed...pick up a roll of those blue shop rags and some Goop hand cleaner. I usually clean off all the discussed engine parts with Simple Green spray solvent and a old toothbrush then give it a quick squirt of water and let it all dry out....you may need to use the shop towels to dry out the pockets and recesses in the intake manifold. Like BD says dont direct the water directly at the carburetor intake or the distributor....should all dry in a couple of hours or overnight.
Yes, the Impala picture you show is the correct numbers of the cylinders and the firing sequence BD gave you is correct.
Yes, the distributor rotor, helical gear, and oil pump blade are all fixed to the same shaft of the distributor and cannot move independently of each other.
As far as rotating the engine to TDC for #1, I usually mark where cylinder #1 is on the body of the distributor (where #1 wire goes into the cap), then take the distributor cap off (dont forget to disconnect the two wire connector at cap) and "bump" the engine over with the starter until the distributor rotor lines up with this mark...you need to make sure the timing pointer on the crank flywheel comes to the tag with numbers on the engine at the same time...sometimes it misses and you need to do it a couple of times till it comes close. I recall it being pretty difficult to rotate the crank by hand if you dont have a complete tool set...I recall you need a big socket, extension, and long socket handle...a wrench cannot get to the nut as it is recessed in the pulley...sorry I do not recall the size off hand.
Some more notes:
-Distributor rotor rotates clockwise when viewed from top of engine.
-Engine rotates clockwise when viewed from front of engine.
-Dont forget: do not rotate engine when distributor is out!
Regards,
Henry
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Reiterating...
Specialized lubricant to coat the distributor gear is not crucial to your circumstances. Just dip the end of the distributor shaft in some clean motor oil right before you install it.
Think about hosing off the back and front of the engine like this: If oil isn't leaking out, water won't leak in. It doesn't require a tremendous flow of water to wash the solvent and surfactants away. As long as the distributor is in the engine, rinse away. Remove any puddled water with compressed air or a disposable rag before loosening the distributor clamp.
Professionals use a flywheel spanner to spin the engine using the flexplate...
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=35665.0;attach=37605;image)
But, if you remove the spark plugs, you should be able to rotate the engine with your bare hands. Or, use a wrench/socket on the harmonic balancer center bolt, being careful to not torque the bolt any tighter. Another method is to insert a large (~18") flat blade screwdriver or prybar between the fan clutch bolt heads and the thick shank of the clutch mounting flange to lever the engine over (assuming properly adjusted belt tension). Any method you use that doesn't involve a flywheel spanner or 'bumping' the engine over with the starter, remove all of the spark plugs beforehand to relieve cylinder compression. It makes turning the engine over much easier.
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Thanks you both very much.
I'll scratch the whole hose idea and just stick scrubbing, light rinsing and wiping away with shop towels.
Furthermore, oil is leaking out (slowly) somewhere, which is why I was skeptical of rinsing it down.
I believe it's either leaking from the pan, valve covers or rear main seal, but that's an entirely different job and discussion.
BD, I was confusing the usage of oil around the base of the shaft housing (what I understood to be the opening in the block for the distributor) with using
engine assembly grease on the helical gear. I read it as two different things. I have 10/30 on hand and will use that instead on the helical gear and the base of the shaft housing.
I'll remove the spark plugs to allow the pressure from the compression to escape. I got that.
Is the harmonic balancer center bolt the center bolt shown in the photo I posted?
If it's threaded, then I can certainly see the possibility of over torquing or breaking it; so lets rule that out.
Are the fan clutch bolt heads the bolts around the center bolt in the same photo?
How do you use a flywheel spanner? Would I have to talk out the fan clutch bolt heads?
What's the best way to turn by hand?
I found this on the 67-72 forum; one person went under the truck and rotated the fly wheel by hand?
http://67-72chevytrucks.com/vboard/showthread.php?t=471806
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Abandon the idea of using the center bolt to rotate the engine. There is too much potential for something to go wrong.
The upper image shows a typical fan clutch that attaches to the water pump at the front of the engine. Do not remove the fan clutch from the engine.
Remove the spark plugs. Insert a narrow prybar or large (18") standard blade screwdriver between the center axle (or pedestal) of the fan clutch and one of its four retaining bolts as shown in the lower image, then pull to bar the engine over. If the belt slips while pulling, simply push against the belt with your free hand to increase tension. (Note that the lower image is of a different engine and fan configuration than you have in your truck and the fan clutch is removed for clarity).
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Hi Spool:
Just to clarify: the helical gear on the bottom of the distributor shaft needs to be lubricated with engine oil but do it just before you put it in or it will drip everywhere and make a mess.
The mating surfaces between the distributor and engine (and the gasket that goes between them) are supposed to be dry...no lubricant and no sealant. This interface will sometimes weep a little bit of oil over time but if your lube it you will definitely increase the amount of dirt and grit that will accumulate at the base of the distributor due to the location on the engine.
Also, if you take the spark plugs out to facilitate rotating the engine by hand, be aware that if you then try to bump it with the starter it will spin much faster.
Regards,
Henry
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Hey Guys,
I'm out there now labeling and cleaning, but I found something...
My personal disclaimer is I've never had more than 1 plug cable disconnected at any given time, and up until this evening did I begin to address each
plug cable by it's respective cylinder number.
In doing so, I discovered my firing order is nothing like the diagram I shared the other day.
I've attached a photo showing the correct firing order to the left and my current firing order to the right.
How is it my truck ever ran correctly in the first place, where do I go from here?
I currently have it wired as shown and have continued cleaning for now.
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I just realized after looking at it longer that it's not necessarily out of order, but the plug connections are shifted counter-clockwise by one terminal connection through-out the distributor cap... Is this terrible?
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Furthermore, these two questions:
Per my first attached image.
I found this severed hose w/ bolt near my distributor bolt... Was this a weak attempt to seal off the opening coming from the manifold in the right of the photo?
Per my second image attached.
I've notice in online videos the vacuum hose from the distributor was connected on the left side of the carburetor, not the right as seen in my photo. Is mine connected correctly?
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(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38486;image)
^^^^ Your truck has the correct plug wire configuration.
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38482;image)
^^^^ Someone simply capped an unused vacuum port. As long as it has a snug fit on the vacuum nipple, changing it will be little more than cosmetic.
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38484;image)
^^^^ There are two encampments regarding vacuum advance configuration - ported vs manifold vacuum. Leave it for now. Worry about this after you get the truck running and the base timing set.
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Copy that.
I'll leave the Carb/Vacuum hose alone.
I'll plug the open vacuum nipple from the manifold with the severed hose and bolt while reinforcing with a zip tie for now, but eventually a hose clamp.
According to the diagram, the firing order is correct but all connections are shifted one terminal left/counter clockwise from the diagram we agreed was correct.
As it is wired now, if I rotate the engine to TDCC on cylinder 1... I'm looking at 5o'clock aerial wise opposed to 7o'clock as the diagram shows...
Is this bad? Should I rewire it? This may explain why some of my plug cables are so long and short, no?
Also, I took off the plastic guard around the radiator fan for easy access.
I noticed the fan moves very easily and independently of the belt; Was this the scenario you spoke of when you mentioned the belt slipping?
If I acquire an extra pair of hands to hold the belts, will I successfully be able to turn the engine?
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Okay. I'll keep the spark plug cables set-up as is.
I'm having trouble turning the engine.
The belts don't move in unison.
If I hold the belt on the fan, the alternator moves but not the flywheel, and hence the water pump.
However, my alternator is maxed out.
The water pump has space to be expanded... But not with any help from my maxed out alternator.
Are my belts too short?
A year or two ago, my alternator would squeak when it was too taught.
Do I need a new one?
1st image: alternator
2nd image: water pump
3rd image: belt of the alternator.
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(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38499;image)
^^^^ To check the belt tension, using a rag or glove to protect your hand from sharp edges, hook/grab the alternator fan with your fingers and try to rotate it using all of your hand strength. If the fan is not held stationary by the belt, the belt is too loose. If the belt slips at its maximum adjustment, you will need to install a shorter belt.
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=38501;image)
^^^^ Once the alternator belt is properly adjusted - if it continues to slip - deflect the belt by pushing downward as shown.
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Hi Spool:
Although your distributor rotation position wrt the engine is not typical for a Chevy truck with HEI ignition, it does not matter as long the distributor rotor hits the correct cap contact at the right time of engine rotation. The ability of the distributor to rotate wrt the engine (and the ability to remove the distributor and slip it to another gear tooth position) allows the engine to run properly with different distributor rotational orientations...having said that, the spark plug wire lengths and vacuum line do become an issue if the distributor is rotated too far from oem spec.
So proceed on as BD has said...no worries...as long as #1 cylinder on the distributor cap is fairly close to oriented to the front of the engine AND the spark plug wires go to the appropriate cylinder with the sequence 1-8-4-3-6-5-7-2 going around the distributor cap clockwise AND the engine ran before smoothly with this orientation, all is well.
Since your truck is a 73 model, it did not originally have the HEI distributor so possibly you have a later engine or someone changed out the old points style distributor for the HEI one and put the new distributor in one or two helical gear teeth off. At a later date you can re-install it with the correct orientation (which keeps the vac hose and spark plug wires at shorter lengths) which is the vac advance can port pointing to the passenger side front corner of the truck and the outlet of the two wire pigtail from the distributor directly behind the carburetor facing the front. We can also talk about the two port vacuum connection on the back of your intake manifold...your plugged connection is probably supposed to go to the vacuum accumulator which supplies vacuum power for one of your air conditioning vent doors.
No fear...proceed on with distributor change out!
Regards,
Henry
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Alright... Making some progress!
I abandoned the original idea of turning the engine by the fan with a pry bar as I couldn't get the belts to move while rotating the fan, even while deflecting the belts.
However, I was able to do it by hand from underneath the truck as seen in this video:
https://www.youtube.com/watch?v=7ORVanWWuro&feature=youtu.be
I missed my mark on cylinder 1 the first time, but after rotating around again I was able to land it spot on as seen in the 1st photo attached.
Now that I have TDCC on Cylinder 1, I'll refer to Henry's instructions posted earlier.
1. Timing Pointer and Wheel are clean. I only have 1 recessed groove in my wheel and will mark it with white out in a moment.
2. Engine will not start, so I'll be skipping this step of seeing how it is currently timed.
3. All my plug cables are correctly labeled.
4 & 5. I left all plug cables on my cap and currently have it sitting on top of my block in front of the carburetor.
I also removed all plug cables and spark plugs from the block to make rotating the engine easier. The cables are currently resting on the engine.
6. I've done a fair amount of cleaning around the distributor but it is hard to get to. (I also noticed the block is actually orange, not black.)
More cleaning needs to be done which I'll be doing in a moment.
7. After more cleaning, I'll be making my marks on the engine block using white-out to notate where the vacuum currently is, and where the rotor is currently pointing at Cylinder 1.
8. I actually had a golf tee lying around to plug the vacuum hose; it worked very nicely. Great idea.
I'll return shortly before proceeding to Step 9. More cleaning and marking for now.
Thank you again for all your help guys.
I really appreciate all your time and patience with my questions. You are greatly appreciated.
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Hi Spool:
If you are only just now discovering that your engine is painted orange it must really be dirty...!!! Up until the late 70s all Chevy truck engines were painted orange so you may have the original engine in your truck. Yeah, I would not be surprised if you use up an entire roll of shop towels on this distributor job.
Dont forget to mark the base of the old distributor wrt the engine before you remove it...you may want to take the old distributor out and then re-install it slowly so you get the idea of how the rotor moves while it is being re-installed. If you are well beyond this now, no problem.
When you get it all back together, dont crank it for long periods if it doesnt want to strart...use short 10 second cranks with about 30 seconds in between cranks until it starts. Your fuel bowl in carb is probably dry after sitting for a few weeks and will take some cranking to get the bowl full again.
Regards,
Henry
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Thanks Henry.
Yes, my engine is filthy; I'm not sure the orange will ever be revealed again as in cleaning it, I would simultaneously remove the orange paint in spots.
I've proceeded to the other steps while successfully removing the old and replacing the new distributor.
I'll attach pictures and videos to share for others in the future.
Returning to Step 1:
I've learned that it would have been much easier to mark my engraved groove on the flywheel while I was under the truck turning the engine for TDCC.
Because I had already found TDCC and removed the old distributor, It was more challenging to mark the groove on the flywheel than it had to be if I approached it differently.
As shown in my 1st picture attached.
Step 7 & 9 from Henry's post earlier in this thread:
I had marked the rotors position pointing to Cylinder 1 after finding TDCC. I made my mark using a sharpie on the actual distributor.
After removing the Distributor Bolt and Clamp, I was able to remove the old distributor with ease while notating where the "Removed Position" was on my engine with more white-out.
As seen in the video: https://www.youtube.com/watch?v=IGi5NW2D2f0&feature=youtu.be
(I used a long flat head screwdriver to line-up my white-out markings on the engine with the rotor's position.)
Step 10: I learned shortly after that I had made the mistake of marking the "Installed Position" on the actual distributor, but not transferring that marking to the actual distributor cap.
With that, I replaced the cap on the old distributor to transfer the mark from the old distributor to the old cap, so that I may transfer the mark from my old cap to my new distributor.
As seen in my 2nd photo attached.
Step 11:
Another mistake I made was not being aware of how easily the rotor and helical gear would move on their own after removing the distributor.
With that, it made no sense in trying to match the orientation of the new oil pump blade with the orientation of the old oil pump blade, so I proceeded to Step 12 with my marking of Cylinder 1's position of the rotor on my new distributor.
(I also, poured a touch of 10-40 oil over the helical gear and oil pump blade of my new distributor before stabbing the engine.)
Step 12: It took a couple attempts to successfully align my oil pump blade with my oil pump driveshaft, but thanks to everyone's help I was able to do it successfully with ease.
I've attached a video here of the process: https://www.youtube.com/watch?v=rUEQ2GGChjo&feature=youtu.be
Additionally, I've attached more images of the alignment following the first two attached images.
After confirming the firing order and such, I felt comfortable removing the spark plug cables from the cap and spark plugs.
Currently, I'm returning to the truck now to torque my spark plugs back into place, rewire the cables with hopes a better configuration as some are too long or too short while installing my
boot plug sleeves as well.
I'll return shortly to report as to whether I can get her to fire up before proceeding to the last step of timing.
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Just to confirm the orientation of the terminal block, is this picture correct?
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Hi Spool:
Looks like you are proceeding along well with the installation. I am not sure what you are referring to as the terminal block...if you mean the projection on the side of the distributor cap with the wires coming out of it, then yes, this is typically on the drivers side of the engine (3 o'clock position if you are above the distributor looking down from the front of the engine).
Dont worry too much about trying to get the routing of the wires neat...it is always a challenge on the old Chevys especially if you dont have the original wire clips. The most important thing about the wiring is not to lay or tie the wires directly together in parallel as this can cause spark crossover and potential misfiring. Wires crossing each other and touching is OK....running parallel for more than a couple of inches and touching is bad. You dont want the wires touching the exhaust manifolds either. If you dont have any clips, the parts stores should have some....I found some good ones at O'Reillys Autoparts made by Moroso. You can worry about these details after you get it timed and running.
Regards,
Henry
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Well, thanks to everyone, I was able to successfully start my truck.
Took it out for a test drive today and everything was smooth. The idling is quieter than was before.
After replacing the distributor and rewiring my plug cables, I had someone rotate the distributor for me as I used the timing light.
When we started it was at 8Degrees AFTER TDC, but it currently sits at 8Degrees BEFORE TDC which was done by turning the distributor ever so slightly counter-clockwise.
I've attached a picture of my Distributor bolt and clamp in place showing the connection on the flange.
As for rewiring my spark plug cables, I took the opportunity to install my spark plug heat sleeves.
They are conveniently 8inchs long which gets me past my headers.
However, 3 of the cables on the drivers side are resting on my valve cover; is this bad?
I was unaware of having spark crossover on parallel plug cables; I'll mix it up a bit.
I want to thank you again for all your help. I was able to learn a lot, fix my truck and enjoy the process thoroughly.
It's a lot of fun, and a lot more fun when it works.
Thank you again.
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The plug wires laying on the valve cover in the way they are pictured isn't optimum because of the potential for rubbing, but it's not an immediate concern either since the valve cover presents a smooth surface. On the other hand, the chrome metal loom holding the wires at the right edge of the image is concerning. The loom should have plastic or rubber inserts that cushion the wires where they pass through the loom. The potential for wire damage and arcing is problematic. I would look for a different solution.
The wire pairs most prone to crossfire are 4 & 8 and 5 & 7. So separate those wires to the outside of any loom.
Congrats on the repair!
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Thanks BD.
Does the valve cover pose a threat to the plug cables due to heat as well, or just friction?
When shopping for wire looms, I can't help but notice they all have the plug cables running parallel; is there a certain distance between any two cables the prohibits spark crossovers?
I'd also been looking at other chrome wire looms as the passenger side of the engine doesn't have one.
However, I see the one I have now is mounted near my valve cover. In removing this bolt, will I also be loosening the valve cover itself?
I wouldn't want to break or compromise the seal I have now on my valve covers.
For wire looms with a with a protective sleeve, maybe something similar to this:
https://www.amazon.com/Proform-141-636-Ignition-Wire-Loom/dp/B0006V2BKA/ref=pd_day0_263_8?_encoding=UTF8&pd_rd_i=B0006V2BKA&pd_rd_r=N7RN2G47R53TBGZ67BEB&pd_rd_w=lhVdX&pd_rd_wg=6zVfp&psc=1&refRID=N7RN2G47R53TBGZ67BEB
And just for sharing purposes/ and a future purchase... How sharp looking is this configuration?
https://www.summitracing.com/parts/rnm-1101-90-k?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-r-m-specialties&gclid=Cj0KCQiAq6_UBRCEARIsAHyrgUzK6VnulcFtbDrBKcLdslAz9tFjmE_7d4yQWr78sLaDRDERqqMl-5caAvhREALw_wcB
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Spark plug wires easily tolerate engine heat. The exception is exhaust heat, which will break down insulation.
I use R & M Aluminum Wire Looms (https://www.summitracing.com/parts/rnm-1101-90-k?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-r-m-specialties&gclid=Cj0KCQiAq6_UBRCEARIsAHyrgUzK6VnulcFtbDrBKcLdslAz9tFjmE_7d4yQWr78sLaDRDERqqMl-5caAvhREALw_wcB) on my 5.7L in an over/under configuration. Drivers side wires are loomed as pictured; passenger side wires route to the spark plugs from below the exhaust.
Whatever style loom you decide to use, make sure the looms are compatible with the diameter of spark plug wires you have.
In itself, removing a valve cover bolt to install a new loom won't invite a leak. But as an added precaution and to set your mind at ease, smear a dab of silicone under the bolt head before reinserting it into the hole. Make sure the added thickness of the loom under the bolt head allows adequate thread engagement. Be careful to avoid overtightening the bolt when reinstalling so as not to distort the cover.
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That's great. You are running the wire looms I was window shopping on. They look super sharp, did you have to order extra long cables for that?
I'm assuming the spacing between the plug cables are far enough to avoid spark crossover?
Mine 8mm, so I'll keep that in mind when shopping.
Also, good to know I remove the valve cover bolt without causing a leak.
Do those bolts actually hold the valve cover down in addition to the silicone between the block and valve cover?
I'm assuming, something as gentle as 22lb/torque as with the spark plugs would be fine in tightening the valve cover bolts again?
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Run 4 & 8 and 5 & 7 along the outer guides of the looms to keep the wire pairs separated as far as possible. Longer cables may be required to use the R & M looms - measure for proper fit. Valve cover bolts are only 1/4" in diameter. Don't use a torque wrench; tighten by hand to less than 5 lb-ft (<60 lb-in). Think of the valve cover bolts as more along the lines of screws. Overtightening will distort the valve covers and create oil leaks where none existed.
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Hi Spool:
Way to go...this is a big job no matter what your experience level of shade tree mechanical work...I am relieved that the oil pump drive connection cooperated so easily.
Yeah, BD is right, the main spark crossover wires are 5-7 and 8-4 since they run a long distance together and fire consecutively. The other spark crossover wires are the 3-6 and 2-1 combos that also fire consecutively....since these cylinders are not next to each other and in fact are in different banks, the only place the wires are close to each other are at the distributor...so they should not run parallel for any significant distance...if they just pass each other or touch in one place that is OK.
What information was provided with the distributor concerning the vacuum advance setting of the distributor? I am just curious and this should not be a point of concern...the vacuum advance is more for fuel economy where the mechanical centrifugal advance in the distributor rotor is for performance. FYI, my Chevy service manual has a typical early 1970s HEI distributor vacuum advance settings of 0 degrees at 4" of Hg and 18 degrees at 18" of Hg for your engine which would be a 350 4BBL V8 with light duty Federal emissions.
Well, your truck should not have any more stalling problems for a long time and if they do start again you should be suspicious of leaking vacuum lines and the fuel system as the culprits as you have all new ignition parts now.
Regards,
Henry
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Well, thanks to everyone, I was able to successfully start my truck.
Took it out for a test drive today and everything was smooth. The idling is quieter than was before.
After replacing the distributor and rewiring my plug cables, I had someone rotate the distributor for me as I used the timing light.
When we started it was at 8Degrees AFTER TDC, but it currently sits at 8Degrees BEFORE TDC which was done by turning the distributor ever so slightly counter-clockwise.
I've attached a picture of my Distributor bolt and clamp in place showing the connection on the flange.
As for rewiring my spark plug cables, I took the opportunity to install my spark plug heat sleeves.
They are conveniently 8inchs long which gets me past my headers.
However, 3 of the cables on the drivers side are resting on my valve cover; is this bad?
I was unaware of having spark crossover on parallel plug cables; I'll mix it up a bit.
I want to thank you again for all your help. I was able to learn a lot, fix my truck and enjoy the process thoroughly.
It's a lot of fun, and a lot more fun when it works.
Thank you again.
Just poked my nose in this thread and have not read the 8 pages but did notice your distributor clamp is on upside down. Is there a reason or is it a goof?
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Just poked my nose in this thread and have not read the 8 pages but did notice your distributor clamp is on upside down. Is there a reason or is it a goof?
You know something... This may explain the situation I had this evening.
After about 4 miles, the engine was idling harshly while in drive at red lights and stop signs.
And upon acceleration, the engine would burp, if you will, almost like if you were running out of gas. Like a stutter before actually accelerating.
When I got home, I looked at the distributor cap markings and they appeared to still be aligned correctly from a distance.
However, my timing light showed it was no longer at 8degrees BTDCC... But way before 14degrees BTDCC, almost at due north.
The groove on the flywheel is timing at say 12'oclock, where my timing tab is at 2'oclock.
All this left me thinking, the distributor slipped as I didn't tighten the bolt enough.
The orientation of the bolt clamp is in the same orientation as when I removed it.
(I've attached the reference photo I took when removing it originally that shows the little bump on the end pointing upwards.)
So, it sounds like I need to time the engine again.
And before doing so, reverse the clamp.
While on the topic, where do you guys set your TDCC and why?
I set it to 8degrees, but the truck feels different than it used to; I never knew what the engine was timing at before I did the job.
Any pros or cons?
Also, Henry, no specs or literature came with the new distributor.
It's a Demotor HEI Distributor 65k Volt, and I didn't see anything online that was specific to this model with regards to vacuum pressure.
Thanks guys.
***EDIT***
I stand corrected... I just noticed my mistake.
On February 13th I posted an image of the clamp caked in grease, dirt and oil when asking the best way to clean it, and it is in fact not in the position of my reference photo.
I must have turned it around while cleaning it... Foolish mistake that I won't make again.
(I've reattached the original image to show my error.)
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i set my base at (been years since i timed it so going off memory) around 12° with the vacuum advance unhooked. and on manifold vacuum instead of ported. than way when the engine is warm it can start up easy and once it gets started im around 26-30° or something like that
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Hi Spool:
Yeah it sounds like your distributor came loose because your clamp was upside down as Vile noted...it will still hold upside down, but it is point contact which is not as solid as surface contact when the clamp is oriented properly and should never come loose when tightened.
I set my engine timing at the specifications set by Chevy...the reason is because the timing of a oem engine is determined by engineers to be optimum for performance, economy, driveability, and reliability. If you have a modified engine (cam, compression, fuel system) you may need to change your timing if the reason you have modified your engine does not suit your needs (hot rodding, racing, making noise...who knows). If you want to modify your engine for fuel economy, the factory timing setting is optimum.
Your engine sounds like it is stock or oem...basically. I see from the photos you have an aftermarket carb, but it is probably 750 cfm air delivery which is the same as the original carb on your engine which was possibly a 750 cfm 4-barrel (Rochester 4MV) or a 425 cfm 2-barrel (Rochester 2GV). Your ignition system was originally the points type of ignition with a separate coil. Now you have the HEI ignition which is a oem style ignition for a later model year (1976 onward) than your older ignition. It is more reliable and requires less maintenance. It replaced the points type ignition to provide a longer and hotter spark for emissions....but this turns out to be good for performance as well.
For your original oem set-up, it is hard to determine what the oem specs were...there were many considering the engine/trans combination and configurations, and whether or not it was a California truck...timing could have varied from 8 to 12 degrees BTDC. Spark plug gap was .035 inch.
For your new oem set-up, I believe the your engine is close to what was a 350 cu in, 4-barrel carb, light duty, auto trans. The spark plug gap is now .045 inch and the timing is 8 degrees for Federal emissions class...it is 6 degrees for California emissions class. Even though you live in CA which has tough standards, I dont think anyone cares or checks what your old truck's timing is...so you can set your timing anywhere between 8-10 degrees for best compromise in performance, fuel economy, and driveability.
*I was only asking about your new distributor's vacuum advance setting because I thought that you mentioned the ad for the distributor said it had a adjustable vac adv setting. I am ignorant about adjusting the vacuum advance...never done it and have never seen any documents showing how to do it for a Chevy HEI distributor. There were no less than 5 different HEI distributors available in 1976 and I think the differences were all in the amounts of centrifugal and vacuum advance...truth be told all would work fine on any Chevy V-8 engine.
Regards,
Henry
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Hi Spool:
I set my engine timing at the specifications set by Chevy...the reason is because the timing of a oem engine is determined by engineers to be optimum for performance, economy, driveability, and reliability. If you have a modified engine (cam, compression, fuel system) you may need to change your timing if the reason you have modified your engine does not suit your needs (hot rodding, racing, making noise...who knows). If you want to modify your engine for fuel economy, the factory timing setting is optimum.
this isnt always the case, most times the engines were tuned for emission reasons. this is why the vacuum advance is on ported vacuum instead of manifold. so it only advances your timing when the throttle is open and you may performance issues (not major). most times for every degree of timing you can advance youll get a small HP gain.
take a read here (http://forum.73-87chevytrucks.com/smforum/index.php?topic=32085.0) by rich weyand
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Alright...
I flipped the clamp, realigned the markings to align at Cylinder 1 and began timing.
I rotated counter-clockwise to align the timing at 8degrees, the only problem is that the engine is not performing well.
It's very rough on an idle and shakes the truck.
The engine sounds like it's struggling to perform.
Any ideas?
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Double check you have the firing order correct and then try advancing the timing. did you validate TDC at zero is truly TDC?
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Hey Vile,
I found TDCC by going under the truck and turning the flywheel by hand until lining up my rotor with the marking on the distributor that indicated Cylinder 1.
https://www.youtube.com/watch?v=7ORVanWWuro&feature=youtu.be
I'll double check the firing order now.
I'll try advancing to 8degrees ATDCC and see if that does the trick.
Is there any harm or foul in turning the distributor too much in either direction?
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The pointer and the indicator need to be at zero when the piston is truly at TDC if you are going to use it to baseline your timing with a timing light. If you haven't done that, in the interim, advance it incrementally until it pings and then back it off. This will help you get it running good for now.
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When I adjusted my rotor to point at Cylinder 1 by rotating my flywheel, it put my groove mark just at about 16degrees BTDC.
I'm going out there now. What do you mean when you say, 'until it pings'?
I'll also be removing the Vac hose and plugging it while I do my timing; something I did the first time but not earlier today.
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Double checked the spark plug connections and the order is correct.
I took the same opportunity to separate any parallel running plug cables and separated 5 from 7 on the loom.
When I went to advance the timing, I found I was choking the engine and anything further than 12degrees ATDC would have the engine stall.
So I began to retard the timing and found that it ran smoother.
It's beyond the timing tab as of now, about 1'oclock on the flywheel, which I would estimate to be about 24degrees BTDC.
I would have kept retarding the timing, but my vacuum is now pushing up against a metal pipe coming from the manifold. (1st photo)
The second photo shows how advanced the timing is in regards to where I found TDC on Cylinder 1 using the terminal of the distributor cap.
The whiteout on the engine being the original spot before removing the old distributor, and the sharpie mark on the distributor itself showing the difference of where it is now.
It's smoother, but it's not smooth.
When I shift to drive, the truck shakes even more.
I'm confused though, because when I did the repair I set the timing for 8degrees BTDC and the idle was super smooth; almost hybrid quiet in comparison to what I had before the job.
Did the helical gear shift inside?
[attachment deleted by admin]
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double check your firing order. Did you reverse #5 and #7?
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Nope, the firing order is correct.
I'll triple check it, but it's correct.
It was based on this diagram attached.
Earlier in the thread you'll see the conversation, but it was determined that the current firing order to the right opposed to the left was correct.
I wired the spark plug cables using the diagram to the right.
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What I'm gathering from our conversation is that perhaps I didn't set TDCC correctly.
Should I remove the distributor, turn the flywheel to 0degrees, replace the distributor and time the engine?
If so, where should my rotor be pointing when at TDCC in this approach? 1st cylinder?
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Thomas, Vile is telling you that in order for you to be able to rely on the timing marks, you first need to verify that the timing marks are accurate. To do so, you need to find TDC of cylinder #1 and then observe whether the timing marks actually align to zero. This will ensure that the outer ring of the harmonic balancer hasn't slipped (a common problem with bonded elastomer balancers) and that the timing tag on the engine matches the painted groove on the balancer (there was more than one configuration of timing marks in production over the years and they are not compatible). I will add that if you are going to verify the timing marks, you may as well check timing chain wear at the same time since it adds only one extra step to the process and provides a more complete picture.
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=49835;image)
^^^^ Incidentally, the "flywheel" is located between the engine and transmission. You painted the timing mark in white on the "harmonic balancer."
...I began to retard the timing and found that it ran smoother.
It's beyond the timing tab as of now, about 1'oclock on the flywheel, which I would estimate to be about 24degrees BTDC.
I would have kept retarding the timing, but my vacuum is now pushing up against a metal pipe coming from the manifold. (1st photo)
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=49836;image)
...It's smoother, but it's not smooth.
^^^^ Your description along with the photo imply that you have "retarding" the timing confused with "advancing" the timing. If you rotated the distributor vacuum advance forward (toward you) until it hit the copper line, you have the timing over advanced, not retarded. Rotating the vacuum advance back toward the firewall (away from you) will retard the timing and should bring the timing mark back toward zero. If I misunderstood what you meant, feel free to correct me.
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...I began to retard the timing and found that it ran smoother.
It's beyond the timing tab as of now, about 1'oclock on the flywheel, which I would estimate to be about 24degrees BTDC.
I would have kept retarding the timing, but my vacuum is now pushing up against a metal pipe coming from the manifold. (1st photo)
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=36058.0;attach=49836;image)
...It's smoother, but it's not smooth.
^^^^ Your description along with the photo imply that you have "retarding" the timing confused with "advancing" the timing. If you rotated the distributor vacuum advance forward (toward you) until it hit the copper line, you have the timing over advanced, not retarded. Rotating the vacuum advance back toward the firewall (away from you) will retard the timing and should bring the timing mark back toward zero. If I misunderstood what you meant, feel free to correct me.
i was about to respond the same thing cause thats how i understood him. the rotor turns clock wise so if you turn the distributor counter clock wise it will be now giving the cylinder fire before it normally would receive it. but it could just been a typing confusion
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ill add this also the harmonic balancer and timing tab cant really be trusted all the time unless youve verified theyre accurate by finding TDC with a piston stop or something . read that article i posted from rich back on
a reply or two down on that theres some links on how to find TDC and timing (http://forum.73-87chevytrucks.com/smforum/index.php?topic=36058.msg305041#msg305041"Reply #116"[/url)
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Hi Spool:
Just to make sure you understand which way things go:
-The distributor rotor turns clockwise. So if you rotate the body of the distributor clockwise you are retarding timing...if you rotate the body of the distributor counter-clockwise you are advancing timing.
-The crankshaft and damper(where you have the groove painted white) rotate clockwise. So when you are looking at it with the timing light from the drivers side of the engine and see it pass the tag on the block, the numbers on the tag above the "0" mark (towards the pass side of engine) are advanced (before top dead center) timing degrees and the numbers below the mark (closer to drivers side of engine) are retarded (after top dead center).
So understanding the above, if you set your engine timing to 8-10 degrees before top dead center (BTDC), where is the port of the vac adv can pointing? If it is rotated close to straight ahead and hitting the carb OR pointing straight left to the passenger side of the engine, then your helical gear at the bottom of the distributor is off by one tooth. Please advise if you can and have not gone beyond this as far as your troubleshooting.
Regards,
Henry
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Okay... First, my own personal corrections of terminology and understanding.
1. I marked the Harmonic Balancer, not the fly wheel. The flywheel is between my engine and transmission. I understand this now.
2. I confused retarding and advancing, but now I understand:
-Rotating the Distributor clockwise is retarding the timing.
-Rotating the Distributor counter-clockwise is advancing the timing.
3. When I originally made the repair of dropping the new distributor in, based on the fact that I believed to have found TDCC by pointing the rotor at the Cylinder 1 terminal in my distributor cap, I in fact was at about 14*ATDC (based on the timing tab) before timing. (First photo attached)
However, after I wired everything up and started the engine to begin timing, I had found that the engine (based on the timing tab) was at 8*BTDC.
I had then went ahead and advanced the timing so that I was at 8*ATDC as I reversed the reading of the timing tabs due to my inexperience and went the wrong way. (I should have left it at 8*BTDC)
Henry, after reversing my understanding of the timing tab and rotations, I went ahead just now and set it to 8*BTDC. (Where it was when I started the truck after replacing the distributor...)
When I did the job, I had the concept inverted and proceeded to time the engine to 8*ATDC.
The truck runs smoother after doing so.
(I've attached a photo of the vac adv can... It's pointing in the same direction when I replaced the distributor.)
Irish, as a newbie, I was able to take away a few solid pieces of information from Rich's page, but much of the information was a little above my hands-on experience and general understanding.
Finding TDC with the hacked spark plug/bolt trick was excellent. Thank you.
After setting my timing back to 8*BTDC and opening the throttle from the carb, I was getting a reading of 8*ATDC with the throttle open.
Would this be about correct?
I don't know how many RPM's I had it though, as I do not have a RPM gauge in the truck.
BD, I've learned my terminology was incorrect and/or backwards.
However, my Harmonic Balancer feels like a solid alloy of some kind. It has rust as well, which leads me to believe it's the original or at least not a Bonded Elastomer.
Overall, and this may be in my head, but the truck sounds "slow" as it idles in comparison to how it was for 3 years of me owning it.
After setting it back to 8*BTDC(based on the timing tab) this evening it certainly doesn't shake like it was at 8*ATDC in idle and performs better in drive as well(with my foot on the brake)
If the truck runs smooth at 8*TDCC(based on the timing tab) and the mistake was due to my own learning curve, do we think it's safe to take for a test drive in the morning?
Here is a link of what the truck sounds like now: https://www.youtube.com/watch?v=BmYpMHpKh5U&feature=youtu.be
Or should more steps be taken to ensure success of actually finding TDC.
If so, what would those steps be?
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Hi Spool:
OK, if you have your engine at 8 degrees BTDC now, and it idles and accelerates smoothly I believe all is well. Go ahead and plug in the vac adv hose from the carb. If you can put it in drive gear and hold the brake and it still idles and is smooth, I believe all is well. Your distributor vac adv port appears to be pointing across the engine at a 45 degree angle towards the pass side headlight which is correct and indicates you have the helical gear meshed properly with the camshaft gear and your plug wires are probably going to the correct terminals...5-7 straddle the B+ terminal under the distributor shroud? I think you are ready to take it for a test drive...the normal idle speed for your engine is 600 rpm for auto and 900 rpm for manual trans. This may seem like a low speed to you because your engine may have been idling too high to begin with. The idle speed for my 76 is 600 rpm and with a quiet muffler sometimes it is hard to tell if the engine is running when you are at a stop sign in traffic...you can just look at the oil pressure gauge and tell if it has stalled or not.
Take it for a drive and advise how it performs.
Regards,
Henry
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Hey Henry,
5-7 do not straddle the B+ terminal of my distributor, but rather are above the B+ terminal.
I've reattached the reference picture that we and BD had last week. (The image on the right being my current wiring)
So I took it for a test drive and was able to tell something was incorrect just by pulling out of my driveway.
I took it back in and ran the following timings to show their results.
8*BTDC with the vac adv plugged using a golf tee.
Park>Shaky
Gas in Park>Smooth
Idle in Drive w/ foot on brake>Shakes
Keeping the 8*BTDC time, but now connecting my vac line to the distributor the timing now reads 12*ATDC
Park>Shaky
Gas in Park>Smooth
Idle in Drive w/ foot on brake>Shakes
Based off of the last result of having 8*BTDC become 12*ATDC with the vac line connected, I began to advance the timing to set it at 8*BTDC while the vac line was still connected.
It's very shaky and giving it any gas causes the engine to nearly die.
I'm stumped.
Little confused as to why the original repair was smooth for 3 days.
Do I need to remove the distributor and find true TDC?
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Also, Sound wise...
This is what my truck used to sound like before the ignition died on January 19th:
https://www.youtube.com/watch?v=NiEHjU8TDxg&feature=youtu.be
(This is at 16*ADTC w/ the vac adv connected)
This is what my truck sounds like when setting the timing to 8*BTDC with the vac adv connected:
https://www.youtube.com/watch?v=Z1QfFVjVY5Q&feature=youtu.be
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ok i think i might have figured it out. your setting timing "thinking" BTDC but in reality your ATDC
(http://image.superchevy.com/f/9593322+w640+h426+q80+re0+cr1+ar0+st0/p109645_image_large.jpg)
not unless that video you posted of your timing is old. but you shouldnt be able to tell 12° ATDC because the timing tabs dont go up that high. and that would also indicate you have something like a 20° vacuum advance
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Thank you, Irish. That is exactly what I needed.
I think this is what happened:
I realized I understood the direction of the timing tab (Before/Left-After/Right), but then confused myself when corrected
of turning the distributor incorrectly to be (Counter/Advance-Clock/Retard)
After all of that, I've come to this.
When I originally did the repair, I did in fact set the timing to 8*BTDC.
It ran smoothly for 3-4 days and then became rough.
When it became rough, I took another timing, and saw it sitting at about DUE NORTH, as I reported a few days ago. (Roughly an estimate of 32*BTDC)
I thought this was incorrect, but now I'm realizing that that was only because the vacuum line to the vac adv was now connected.
I went out and did the following:
I set the truck to 8*BTDC on the timing tab with the vac plugged.
-Park>Smooth
-Park w/ gas>Smooth
-Drive>Smooth
Then I tightened the distributor bolt very hard.
Took a timing and found I moved it to 9*-10*BTDC (Which I accepted and proceeded)
I reconnected the vac adv and took a timing of DUE NORTH again, which I'll estimate to be 32*BTDC, the same place it was when it started to run rough...
However,
-Park>Smooth
-Park w/ gas>Smooth
-Drive>Smooth
Conclusion:
The truck is running smooth when set at *8BTDC and moves to DUE NORTH/roughly 32*BTDC when I reconnect the vac adv.
However, this is what I did the first time, minus taking a reading after reconnecting the hose.
So when the truck began running rough and I took it home to discover the WHITE GROOVE at DUE NORTH, I thought the distributor slipped, when really, it was most likely the advance of the vac adv.
Which leaves me questioning, perhaps it was correct originally, I confused myself twice-over when timing the second time after I corrected the orientation of the distributor clamp.
I'll go for a test drive.
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(http://imgur.com/NeIv5Tu)
The reason I stated your advance is around 20 because think of it a math problem
-12, -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1,BTDC 0 ATDC 1, 2, 3, 4, 5, 6, 7, 8,
You said you set the initial timing to 8°ATDC. Once you connected the vacuum advance it would go to °8 BTDC that's a total of 20° difference. If you then set the initial timing at 8° BTDC the advance should bump it up to 28° BTDC.
But anyway we all make mistakes, how did it test drive?
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Exactly. Thank you for that.
That was the visual I needed.
...-5, -4, -3, -2, -1, BTDC 0 ATDC 1, 2, 3, 4, 5... from left to right when looking down on the harmonic balancer.
And CounterClockwise>Advances, while Clockwise>Retards on the distributor.
When I scrolled back to my post on the 25th, I noticed that I had my understanding completely backwards.
My test run went smooth; ran a few errands and my start ups, idles and runs were smooth.
Everything sounds good too; the exhaust sounds familiar, yet the idle is a little quieter than before, but nice.
I'm a little skeptical to push it, but locally, the test run went great.
I'll be on the highway in a day or two for work.
(I'm keeping the timing light and distributor wrench in the truck for now... Even though I tightened the distributor bolt pretty good.)
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We've talk before on here about those lopy sounding trucks are better for higher rpms situations. Our trucks need the power right off the start to much all that weight. It also sounds as if you have your vacuum advance on manifold vacuum which is better for performance also. On ported vacuum it only advances ones you open the throttle and the vacuum catches up. So you might get a little bit of throttle "lag" but on manifold vacuum it's advanced once the engine starts which is better for performance but a little worse for emissions. Which is why they came ported from the factory to meet emission requirements.
Once you get a better understanding on how the truck is running I would try to get a few more degrees out of the timing, normally what I do is get the engine warm from driving it normally and advancing the timing to where the starter almost sounds as if it was weak or the battery was dead and back the timing back a few degrees. Then check to see if you can get it to ping, pinging is bad it's from the cylinder detonates too soon and can cause engine damage
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Hey Everyone.
Just wanted to extend my gratitude and appreciation to everyone further.
It's been about a week and the truck proves to be running great.
Had an opportunity the other day to punch it a bit on the freeway and it was super smooth and super rewarding.
Thanks again guys.
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glad to hear we could get you back on the road (http://www.naioa.com/v2/modules/Forums/images/smiles/burnout.gif)