Author Topic: New to me 350 advice  (Read 4783 times)

Offline tc197

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New to me 350 advice
« on: February 05, 2018, 08:59:15 PM »
The 350 in my 87 v2500 (tbi) started knocking at the end of this summer and wasn't driveable. In the past few weeks I've finally gotten around to working on it. I originally decided I was going to just buy a crate motor, fix some wiring and call it a day so I pulled the old motor out. I started going through the wiring harness and figuring out which connectors were in need of replacement, patched a few rust spots on the firewall, and got ready to start looking into crate motors but then last week I found a running 350 not far from me that was still in the truck for 150$, the only catch was I needed to pull it myself. After a long cold Saturday I drove away with my "new" motor and all the accessories. I started it up when I got there and it sounded and looked great. It showed good oil pressure on the gauge, ran smooth, and looked 10 times cleaner than what came out of my truck. I was told it was a replacement motor with about 65k miles and it was in a 94 Yukon and setup for TBI. I walked away with the fully dressed motor complete with intake, tbi setup, distributor, power steering pump, alternator, water pump, sensors, air filter unit, etc and also a bunch of the wiring connectors.

There are a few difference between the motor that came out of my truck and this new one that I can see right away. The new motor's tbi unit has two mounting posts for the air cleaner whereas my old motor only had one central post, the new motor has an oil cooling unit, the new motor was hooked up to an auto trans whereas I have an sm465, the alternators are mounted on different sides of the motor and the new motor has an additional bracket that I think was used with the air conditioning in the Yukon. As far as I know I shouldn't have any issues getting this motor into my truck.

My question is if I should do anything to this "new" motor before putting it my truck. I'm torn in the sense that this motor was running fine when I took it out so why mess with it, yet since it's already out now would be the most convenient time to address anything with it. This is also my first go around with this sort of work. Two weeks ago was the first time I pulled a motor and Saturday was my second - I've yet to reinstall one and I've yet to take one apart. The one number on the block I've been able to find so far is 10054727 which I believe indicates an 86+ 350 block, 2 or 4 bolt main, and 1 piece rear main seal.

The truck is nothing special and probably has more than it's fair share of rust and wear. Should I just run with it and see if I get a few years out of it as is? Or is it simple enough to open it up and look things over without causing new problems? Any advice would be appreciated, thanks!

Offline Irish_Alley

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Re: New to me 350 advice
« Reply #1 on: February 06, 2018, 07:46:06 AM »
the only thing i would think about working on is the accessories. if you use your old wire harness out of your truck you may find it may not reach the alt. or something else. if memory serves me right you can buy a bent air cleaner stud that will adapt your newer tb to your old air cleaner
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Offline tc197

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Re: New to me 350 advice
« Reply #2 on: February 06, 2018, 09:26:53 AM »
I am planning on using the old wiring harness so I’ll have to check on the length to the alternator. I am also replacing the alternator so if need be I should be able to switch it back to the other side of the motor. I have all the brackets from the old motor at my disposal as well. As far as the air cleaner goes i was able to take that in addition to the motor so I have both the old single stud and the new double stud air cleaners. Unless theres something else unique about the two air cleaners I was planning on just using the new one I got with the new motor. Good to know that there may be an adapter if need be. The other thing that inspired confidence was the block number stating 86 and up, i assumed there would be minimal changes necessary to get it into an 87 then. Thanks for the tips!

Offline Captain Swampy

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Re: New to me 350 advice
« Reply #3 on: February 06, 2018, 09:03:50 PM »
It's a good time to install a block heater if you live in a cold climate. I would be tempted to put a cam in it. You need a cam that maintains high vacuum to work with the MAP sensor.  tbichips.com has a list of recommended cams for TBI engines.
1987  350TBI 700R4  4X4  4.56 gears  33" BFG All Terrain


http://forum.73-87chevytrucks.com/smforum/index.php?topic=32209.0

Offline PatrickM

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Re: New to me 350 advice
« Reply #4 on: February 06, 2018, 09:39:29 PM »
I did something similar a few months ago. I put a 95 Tahoe 350 in a 89 pickup. I swapped all the electronics from the old 305 over to the new motor including the throttle body. I put the 350 injectors in the 305 throttle body. I can't help you on the alternator though.

Offline tc197

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Re: New to me 350 advice
« Reply #5 on: February 07, 2018, 07:05:14 PM »
Thanks for the tips guys. Ill check out tbichips.com. I like the thiought of putting a new cam in it, just cant decide if now is the time

Offline tc197

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Re: New to me 350 advice
« Reply #6 on: March 17, 2018, 07:25:31 PM »
Hey so I've been working my way up to dropping this new to me motor into my truck. I've just about fixed all the wiring in the truck and I'm hoping I can get this new motor in next weekend.

On the new motor I have:

-fixed two broken bolts for the temp sensor housing. Tried drilling and using a screw extractor, the extractor snapped off in the bolt and it took me an entire day of dremmeling to drill out the broken extractor and original bolt. I tapped the hole and remounted the housing.

-replaced the alternator with a cs130 and got the wiring adapter to match my 87's harness.

-removed the oil cooler lines and attached an oil filter adapter

What I'm working on now is making sure that everything on the motor matches up with the harness/truck while it's still easy to access and I've come across a couple questions and I attached some pictures to help.

1. The new motor was attached to an auto trans when I pulled it and my truck is setup for an sm465. Should I keep the flywheel that came with the new motor or swap to the flywheel I originally had in my 87? Based on the searching I did on here I cam across a couple statements along the lines of "use the flywheel that matches the motor" but just wanted to confirm. The old flywheel is like twice as thick as the newer flywheel and the newer flywheel also has large holes (weight reduction?) cut in it.

2. Piggybacking on the flywheel question, it looks like the newer flywheel doesn't have a pilot bearing/bushing? My old flywheel setup does and it reduces the diameter to like 1/2" or so. If i use the new flywheel do I just press a new bearing/bushing in there?

3. My old water pump has a plug in the upper most hole, the new pump has a hose fitting instead of a plug. Can I plug this to match what I had?

4. My old tbi has a plug in the hole just in front of the distributor, the new tbi has a fitting with a small diameter hose. I'm not sure where this hose goes. Can i plug this to match my old setup?

5. My old motor has some sort of sensor near where the oil filter attaches and the new motor doesn't have this at all. What is this sensor?

I have a few more connector questions but I'll stop here for now before I get ahead of myself.

Offline tc197

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Re: New to me 350 advice
« Reply #7 on: March 17, 2018, 07:27:59 PM »
One more pic.

Offline tc197

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Re: New to me 350 advice
« Reply #8 on: March 17, 2018, 08:58:20 PM »
I was just doing some more reading and may have answered my question 5. Please correct me if I'm wrong.

On my 87 motor I believe there are two oil pressure units. One is by the base of the distributor and it has 2 wires. The second is pictured above near the oil filter and has a single wire connecting to that exposed terminal.

On my new 94 motor I believe there is one oil pressure unit and it is only at the base of the distributor, but has 3 wires.

Am I correct in thinking that the 2 units from 87 were combined into 1 three wire sensor on this 94 motor? If this is so, I should be able to splice the two wire connector and the one wire connector from my 87 harness to the 3 wire connector of my 94 motor and be good to go?

Offline tc197

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Re: New to me 350 advice
« Reply #9 on: March 24, 2018, 09:34:59 PM »
In case it helps anyone else, I realized my questions 1 and 2 aren't even really questions. I learned last night that an auto trans doesn't use a flywheel like a manual trans. They look the same in that they have the same tooth count and diameter but the auto trans uses a flexplate and not a flywheel. This made it pretty easy to decide that I needed to use the flywheel from the old motor, and to answer question 2, since the flexplate is for an auto trans it makes sense they didn't have a pilot bushing in there.

Today I swapped the flexplate for the flywheel and bought and installed a new pilot bushing. I also plugged the tbi/intake outlet (question 4) to match my old setup. I wanted to plug the water pump (question 3) but the fitting currently in there doesn't want to come free and I don't want to break it off. I might just come up with a way to leave the fitting in place but still plug it.

The thing I'm most hung up on now is the TPS (throttle position sensor). The tbi unit on my 87 is old and worn so I'd prefer to use the tbi unit on the 94. The only difference between the two that I can see is the 87 uses a flat three prong TPS unit whereas the 94 uses a triangular 3 prong TPS unit. The two TPS units can't be swapped because of the mechanical way they connect to the tbi unit so I see myself with two options: 1. swap the old 87 tbi unit onto the new motor or 2. leave the new tbi unit and splice the correct connector into the 87 wiring harness.

I'm leaning towards option 2 but I'm not positive that it will work. Both tps units are 3 wires (the same colors) but I'm not sure how the signal will be read on the different units. If anyones tried this before and knows if it will or will not work I'd appreciate the advice.

Offline Ol Blue

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Re: New to me 350 advice
« Reply #10 on: March 25, 2018, 07:58:57 AM »
Thank you for writing updates to your queries. It helps those of us learning our way through some of these issues.

Offline tc197

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Re: New to me 350 advice
« Reply #11 on: March 25, 2018, 09:59:55 PM »
No problem!

Today I spent most of the day wrestling the new motor over to the truck. I work in car port tents in the yard and I had the truck in one tent and the new motor on the other side of the house in another. My harbor freight hoist and the engine stand I have are not meant for rolling through dirt/grass/snow.

I spliced the newer triangular TPS connector into my 87's harness and I'm thinking it should work fine. I did some reading online and found some old posts about people doing something similar and not having issues. I'll have to wait and see if its true.

At this point I believe I'm ready to drop the motor in. There's not much I haven't tinkered with while it's been out.
-new steering stabilizer shock
-new motor mounts
-patched holes in the firewall
-new blower motor resistor
-new wiring for the sound system
-new wiring for a winch
-new wiring/added a relay to a roof mounted strobe light
-new headlight/side lamp wiring connectors and relays
-new positive and negative junction posts to avoid having 1203 things connected to the battery
-all new ground wires

On the new motor:
-new cs130 alternator with the adapter to the 87 harness
-new plugs/wires
-swapped most of the sensors from the old motor over
-removed the oil cooler and installed the adapter plate
-swapped the old flywheel over in place of the flexplate
-new clutch pilot bushing

Next chance I have I figure I'll get the motor in because anything else I need to do should be just as easy with the motor in as it would be with it out. Once it's in place I'll:
-Connect up all the sensors and see what's left over for connectors and what I've missed
-Put the radiator back in
-Connect up the fuel lines, power steering, brake vacuum line (i think that's what it is), etc.
-Add oil, coolant, etc

Unless I've missed something I think I should then be good to try and start it up and see what happens. Once i know it's running I'll get the trans/tcase back in and button everything up. I'm going to replace the gaskets and seals on those first anyways.

Assuming the TPS sensor splice works, I know there's a few other issues I need to sort out:
-the 2 wire + 1 wire oil sensors vs the 3 wire single sensor
-I have a single pink wire headed toward the ECM with no connector on the end of it, don't know what that's for.
-I have a single orange or light brown maybe tan wire coming from the bulkhead connector with no connector on the end of it, also don't know what that's for.
-Still need to plug the extra outlet on the water pump
-Need to decide on the correct starter wiring and alternator wiring. I'm pretty sure sometimes the starter was used as a junction point and I don't see the need to do that so I'll have to do some reading on this
-I need to verify where I need fusible links and if I can substitute inline fuses instead. I just don't like fusible links. It seems much more convenient to be able to replace a fuse and know that it was blown or not blown but maybe I'm wrong.

Chances are I'm missing a few things but they'll turn up sooner or later as new problems.

Offline tc197

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Re: New to me 350 advice
« Reply #12 on: March 30, 2018, 10:13:35 PM »
I was able to get the motor almost into place today, I'm still fighting one motor mount bolt which should be resolved in the morning, it was harder than I expected getting those to line up.

I did some reading (from an old thread of mine) and decided on the plan for the alternator/starter wiring which is to keep it simple and how its supposed to be. The fusible links are designed for high current and are slow blow fuses so I'll keep it as designed.
-New cable from the battery to the starter.
-2 new fusible links, one for each circuit, running from the starter to the bulkhead connector. I bypassed the junction block in the past because I only ever had one wire in and one wire out, so there is no need for the redundant 3rd fusible link as far as i know.
-New ground cable for the starter probably straight back to the new ground junction post i installed.
-New low gauge cable from the battery to the alternator and new low gauge ground cable from the alternator bracket back to the battery. I believe I'll be using 1 or 1/0 gauge.
-New ground cable from the back of the passenger side cylinder head to the firewall

After soaking that extra water pump fitting in penetrating oil I was able to get it free and properly plug the hole.

Hopefully tomorrow I'll get all that wiring in place and get that motor mount bolt tightened up. If that goes smoothly I'd like to connect up all the sensors and see what wires I'm left with that aren't connected. Still haven't figured out the pink wire or orange/lt brown wire so I know those won't be connected to anything yet.

Does anyone know if I can get away with testing/attempting to start the engine with no radiator hooked up? I'd put a rag over the inlets/outlets just so any coolant doesn't get sprayed all over. If I have to connect the cooling system first it's no big deal, just figured I'd save myself the time in case it doesn't start or I need to pull the motor back out for some unknown reason.

Offline tc197

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Re: New to me 350 advice
« Reply #13 on: April 02, 2018, 09:31:29 PM »
Not a ton to report on. I got that last motor mount to go so it's bolted down now. I was also able to start connecting sensors and getting the wiring into place. I realized the fitting for the brake line on the tbi unit is a different size, the power steering lines don't match up correctly, the heater lines don't match up nicely without some crazy bend and the gas lines don't fit due to the new location of the ignition coil. All should be relatively easy fixes.

Offline tc197

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Re: New to me 350 advice
« Reply #14 on: April 22, 2018, 09:08:24 PM »
Lost a few weekends so yesterday and today was my first chance to get back to it.

-I swapped the fitting for the brake booster to the intake and got that bolted together.
-Swapped the old power steering lines in and got those connected up.
-Got the fuel lines connected
-Finished up 95% of the wiring I think I need to do: I have 4 or 5 wires/plugs that I'm still not confident on.

Today I hooked the battery up and checked all of my electrical work. At first I had no headlights, radio, or horn but I soon found I wasn't getting power through both red B+ wires. The way I had wired it was one red wire from the starter to the firewall bulkhead and the other red wire from the alternator straight to the firewall bulkhead. After some head scratching I realized that that the alternator to bulkhead connector needed to also connect with B+ and once I ran a test wire I had headlights. At this point my sound system works (subs, amp, head unit, everything), my front and rear led light bars work, headlights work (with updated heavy duty relay harness from  ), blinkers work, brake lights work, and my plow light works. My horn isn't working, but I can hear the relay clicking when I hit the horn so I know it's getting power to at least there. I'm feeling good about everything wiring related though.

This was as far as I got this weekend but now I'm ready to try and crank the engine over next chance I have. The trans, tcase, and cooling systems are not connected.

The only other issue I'm noticing right now is that my check engine light is not coming on when I ignition on. I'm going to have to read into this a little bit.