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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 1979C20 on April 08, 2011, 04:37:47 pm
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Number 2 plug wire was melted and it missfired often, so thats why its fouled. And I used a wire brush on number 1, but it looked just like 3 and 5. Other than that, whay can be said about these plugs? My carb was set very rich for quite a while. I have adjusted it leaner, but its still a little rich. Thats how I want it because it makes my cam more noticeable. Can I wire brush these plugs and reuse them or should I replace them? They are currently all gapped between .045 and .050. Should they be re gapped or left alone? Thanks guys.
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Thats very rich.
The insulator should be a mild tan. Also that crud on the electrodes is not good.
New plugs gapped right and lean out your carb...
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those look horrible; replace them, your wires and set your carb, timing etc properly. Also replace your cap and rotor if it's been a while.
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Is it reasonable to say that 4, 6, 5, and 3 are decent comparitively? now, these are the same plugs that have been in the truck sonce june, so theyve been through lean, then super rich, then about normal. The timing is at 8°. Cap is brand new, rotor is fairly new. I replaced the burnt plug wire. Gonna look into plugs next week. R43TS's, where should I gap them? Stock 350 with a mild cam "biggest cam you can use with stock valve train". Stock qjet, usually runs about 175-190°
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I would gap them at .040 but it really depends on your heads etc you could try anything between .035-.055. I would try a little more adv and see how it runs after you get it running with new plugs and get your current problems solved. That is my opinion on your set up but there are probably more qualified people here and some may have better ideas than myself.
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They are stock heads. If I advance it too much but it backfires through the carb when accelerating or if I crack the throttle real quick.
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shouldnt it ping before it backfires?
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well get it running good . Your adv is fine at 8, I just a saw possible opening for a little better performance but if you know it doesn't work then you already have your answer. If you don't have headers they might be a nice next step if your budget allows.
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I have headers. But with those headers came a horrible header leak because my flanges are warped. Im going to silicone around the ports like on sprint cars and call it good. My carb really needs a rebuild. The float is starting to stick and it leaks fuel into one of the vac lines. Once I get the carb rebuilt I will buy new plugs and shortly after new wires. Or should I get new wires then plugs. anf I will advance my carb a bit. The problem with advancing my timing is that I have to adjust my idle screw out a bit, and im already having problems with the throttle not wanting to return all the way to the idle screw. Thanks guys.
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1979C20, just a thought, I replace my distributor ( points ) with a hei today because my old dist. was toast and I wanted hei, when I pulled my plugs they looked like yours, check to make sure your dist. is putting out enough voltage.
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Its hei, how do I check for proper voltage? I put a new cap and coil on in july. And the rotor, etc is used.
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First off since you said the rotor was used, take off the cap and make sure the rotor is clean with no carbon build up on the center or edge connection points. Here is a good article on how to check your distributor for weak spark, bad pick up coil, etc,etc. Hope it helps, and keep us informed on what you find. http://www.ehow.com/list_7717560_signs-pick-up-hei-distributor.html
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Okay, I leaned my carb one 1/2 turn on both sides, and advanced my timing. Can you guys explain how to read my timing tab. TDC is in the center of the circle, correct? That is when my number 1is tdc. What are the marks on the tab?
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0 on your timing tab is TDC. looking at the marks from the front of your truck, to the left is before TDC, and to the right is after TDC. It looks like you might need to clean up your timing marker, at least I could not see any numbers, each "tip" of the marker should be 4 degrees, at least on my 74 350 that I timed yesterday that is the way mine is set up. Hope this helps.
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Okay. I cleaned my timing tab. I sprayed brake cleaner on it and scraped the paint/grease off of it. I reestablished tdc on the timing tab and then moved my rotor. I checked for carbon build up on the points. I put everything back together. When I started her up initial timing was at exactly tdc, then I adjusted it to 6-5. Then adjusted my idle to about 550-600. Starts fine, the plugs look exponentially better compared to before. I wire brushed the old ones and re used them until I get paid. Now they are golden brown, like a lightly roasted marshmallow. Before, my mixture screws were about 4 1/2-4 3/4 turns out. Now they are 5-5 1/4 turns out. rev to idle return is quick. Thanks a lot guys. Im going to buy new plugs soon and when I buy plugs I will check the wires with an ohm meter. Thanks a lot guys.
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Well, I took her for a test "race" and now it has low power. And slow acceleration. It was a loooot faster before I changed the timing. And it backfired through the carb. How to I check for pinging? Can it be heard at idle? Because while I was adjusting my carb i could hear what sounded like beans rattling fast in a can. Maybe my balancer slipped? And my timing is advanced too much? I have no EGR, I removed it because of.really rough starting when it was in the 40's here. It would missfire baaaad and I had to try and get the rpms up to 3k with out it stalling and hold it there for like a minute to clear it out and even the idle.
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Removing your EGR because of poor cold starting accomplishes nothing. Your timing needs to be set properly, your carb has a choke to control cold starting and that must be set properly, as well as your mixture.
I am betting your issues all stem from the fact that you are running an overly rich mixture as evident in your original post.
Get back to your base timing, Adjust your mixture properly. Then you can start advancing the timing and readjusting the carb as the idle will change as the timing changes.
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Well, I even came on the forum about the truck not wanting to start in the cold abd they said it was probably the egr. I removed it and havent had any issues. And, once again, how do I check for pinging?
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you will hear it, usually when accelerating or when the engine is under load.
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Well, I have headers and glasspacks that dump right under my seat, so I cant hear anything while accelerating other then "ROOOOOAAAAARRRRRR". So, is it possible to tell from under the hood where it isnt quite as loud. What sound am I looking for? Is there any other way to check for pinging?
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Advance it a little more. If it's too far, it will kick back at the starter when you crank it over. If it does that back it off some, or if your tab is accurate try 10, then 12, etc. With your manual trans you can run low rpm in high gear so it's under load and lean into the throttle a bit and you might hear pinging over the exhaust. That would be a giveaway of too much advance.
That sounds like a lot of turns out on the idle mix screws for a q-jet, but I guess the plugs don't lie. Good luck
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And just so I kniw im not just retarded, advancing, you turn the distributor counter clockwise's and retarding youbturn thw distributor clockwise, correct?
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On a sbc turn it counter clockwise to advance, clockwise to retard, when looking at it from the top.
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I did the nm low rpm in high gear thing. I did not.hear anything that sounded like pingin. So ill try advancing my timing. Ill advance it, adjust.thr.idle, then shut off and restart to check for kick back.
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You stated that the engine has r43ts plug's in it. That plug is too cold for that engine. I would definitely put in R45ts. This plug will burn hotter keeping your plugs cleaner. I would gap them at .40 or .45.
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No, im planning on buying r43ts's. I have a set of auto lites that checker said are for my truck. Well,.my engine was pinging at idle. I retarded the timing and its not making the beans in a can sound, and its running a lot better. So it was pinging, which is probably why it ran like crap.
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If you have it set where you like it make sure to read the tab so you have a baseline to go back to.
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Well, I went out to my truck this morning and it wouldnt even sputter. So I checked and had no spark. I checked the power lead at the cap and it was good. A month or so ago my distributor gear ground down to nothing and stopped turning. I got an old distributor from a family friend and threw it in to get it working. I figured it happened again, so I pulled the cap and checked to see if the rotor turned when I cranked the engine. It did, so that wasnt the problem. So, I grabbed my old distributor with the chewed up gear. it was fairly new, as were the internal parts. So I swapped out the ignition control unit and the condensor, put it back together and It started right up. Im going to swap in a new pick up coil, probably when I do the plugs. Im going to play with the timing tonight, I think I can still hear some pinging, but im going to make sure I get as much advance as I can. Also going to recheck the plugs and see how their burning.