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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Jon87V20 on July 18, 2019, 07:45:22 pm
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Hey guys,
I bought a re-manufactured 350 for my '87 Suburban V20. I have the engine in the truck and my next step is putting the intake manifold on. I bought a Edelbrock Performer TBI for it since my OEM manifold was getting pretty crusty.
I started getting nervous about putting this on because there's these little metal plates in the intake gaskets I bought that cover the rear-most ports on both sides (see photo). Aren't those ports for the water jacket? Why would you want the flow restricted to the size of the tiny holes in the plates?
I did look and verify the old motor had those plates there on the old gaskets. Should I still keep those blocked with the new manifold?
Also, I noticed the center port on the driver's side cylinder head is present, however on both the new intake manifold as well the old one, there isn't a corresponding port. The old intake just has a square of carbon build up there where it was up against that port. Do I need to worry about this at all?
Also, there was a paper that came with the new engine that has some information on it regarding using restrictors for different years and applications (see other photo). However, I don't see 1987 covered on here and am not sure what to do or what not to do.
Sorry... more questions. There was a warning label bundled with the new engine's papers that says "Valve lash must be checked at install and adjusted after 2 to 3 heat cycles." I believe this has hydraulic lifters. Do I still need to do this?
Lastly, when I first bought this truck years ago, the A.I.R. pump was completely seized up and had no belt on it. I just removed it as well as the piping that was attached to the exhaust manifolds. The heat-riser tube is also gone. I'm worried now that I shouldn't have been so quick to just tear that stuff off. Will those components being removed have any negative effects on the new engine? Do I need to go find this stuff and put it back on?
Thanks so much for the help. Just trying to be really careful and do everything right the first time so I don't wreck this motor right away.
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Number: 90-12-6A
Section: 6A
Date: JUNE 1989
Subject: INTAKE MANIFOLD GASKET INSTALLATION
Model and Year: 1987-90 LIGHT DUTY TRUCK WITH 4.3L, 5.0L, 5.7L TBI ENGINES
TO: ALL CHEVROLET DEALERS
This bulletin is for informational purposes only, and should be used as a guideline if it becomes necessary to replace the intake manifold gaskets on 4.3L, 5.0L and 5.7L TBI engines.
With the introduction of TBI engines, a change was made to the intake manifold gasket by adding a restrictor plate to the rear coolant passage of the gasket in order to direct coolant to flow from the front of the intake manifold, under the TBI section of the manifold (heats TBI to prevent throttle plate icing) and exit out of the heater hose pipe at the rear of the manifold (See Figure 1).
Anytime it becomes necessary to replace the intake manifold gasket, it is essential that the gaskets be properly installed. If the gasket is installed backwards i.e., with the restrictor plate at the front of the engine, the engine will overheat. When diagnosing overheat conditions, the proper installation of the gasket can be checked without removing the manifold. Both the 4.3L, 5.0L and 5.7L gaskets have metal locator tabs that can be seen sticking out from between the manifold and the cylinder head. When installed correctly, the tab on the 4.3L will be to the rear of the engine and the tab for the 5.0L and 5.7L engine will be to the front of the engine (See Figure 1).
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Also, I noticed the center port on the driver's side cylinder head is present, however on both the new intake manifold as well the old one, there isn't a corresponding port. The old intake just has a square of carbon build up there where it was up against that port. Do I need to worry about this at all?
Also, there was a paper that came with the new engine that has some information on it regarding using restrictors for different years and applications (see other photo). However, I don't see 1987 covered on here and am not sure what to do or what not to do
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Since you do not have this port in your intake manifold, you need not worry about it.
Sorry... more questions. There was a warning label bundled with the new engine's papers that says "Valve lash must be checked at install and adjusted after 2 to 3 heat cycles." I believe this has hydraulic lifters. Do I still need to do this?
This is their way of covering their butt's if the engine starts ticking, they're putting the additional lash adjustment on you. If it's quiet, leave it alone.
Lastly, when I first bought this truck years ago, the A.I.R. pump was completely seized up and had no belt on it. I just removed it as well as the piping that was attached to the exhaust manifolds. The heat-riser tube is also gone. I'm worried now that I shouldn't have been so quick to just tear that stuff off. Will those components being removed have any negative effects on the new engine? Do I need to go find this stuff and put it back on?
Thanks so much for the help. Just trying to be really careful and do everything right the first time so I don't wreck this motor right away.
Where do you live? Is there emissions inspections for this vehicle required? If not, then you can run headers, a 180° T-stat and a custom chip if you want to help wake it up a bit more. Simple upgrades
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Where did you get the engine?
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Disaster struck today guys. While I was filling the radiator before the first start up, water started pouring out of the distributor hole in the manifold (distributor wasn’t in yet). All I can think of is the gasket wasn’t properly in place and the motor was completely filled with coolant.
I drained it all out via the oil pan drain plug. I’ve filled it back up again with oil. I’m going to drain the oil out again, then pour oil all over under the manifold when I take it back off. Also, I’ll probably pour oil all over the rockers on both sides, then spin the oil pump with a drill before I drain it back out again.
Will I be okay after all that, or is this engine a lost cause now?
Thanks guys.
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Wow man! I thought I was the only guy who did stuff like that!
Seriously, I think you're okay, you didn't 'inhale' any coolant into oil galleys by running the motor.
Flushing it out is a good idea, you can use 'motor flush' as a lighter liquid solvent to move out the remaining coolant.
You can reuse the solvent as the coolant separates, pour off the solvent and continue to rinse and repeat.
Not sure what you want to accomplish by turning the oil pump- at this point any coolant that got into the was blocked by the oil in the pan. Sounds like your drained it right away so the risk of it settling down to live 'beneath the oil' is slim.
I would just rinse and repeat till there isn't any sign of coolant, then let the oil pan plug and oil fill cap stay open so the coolant can evap.
You'll be fine! Did you find out how the coolant got away from you in the first place?
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Johnny, I believe I figured it out. I bought a new TBI Performer manifold and when I pulled it back off the engine after the water fiasco, I saw that there’s two ports on the bottom where the coolant runs through that were open. I guess you could say it’s on me for not noticing this before installation, but I would’ve expected it to be mentioned in the instructional sheet or there to be the fittings included in the box. But no. No mention of this major hazard whatsoever. Maybe it’s typically common knowledge but I had no idea. Not too happy about it. You live and you learn I suppose.
What would be the need for having those there? Why would you ever need to let water out through there?
Thanks for the encouragement. I’m feeling less hopeless about this now.
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I think I would be deep into TBI's mix right now, asking about their design and why these ports exist at all?
They hover above the valve train components, can't imagine their purpose?
I think there is some 'splainin to do, and ask for a store credit if it's their boo boo.
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i don't think the engine is a lost cause simply because of the water.
i think it MAY be a lost cause due to where you got it from.
Where did you get the engine from?
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Stewart, I bought it from Jegs. It's a Mexican reman.
Another question: I'm going to start it up tonight or tomorrow for the first time. From what I understand, you're suppose to run it at 2,000 rpm for about 20 - 30 minutes to break-in the camshaft.
I know you're not really supposed to mess with the idle screw on the TBI. However, I'm not really trying to sit and hold the throttle for that long. Especially since I want to be able to walk around and check for leaks. Is it okay to temporarily turn the screw in to hold the idle for me if I mark where it was and put it right back?
Will this cause the ECM distress and throw codes etc.?
If I could, I would just take the springs off but these don't just simply come out. Any tips or tricks from experience with holding the idle? I don't have a helper to hold the pedal either unfortunately.
Thanks!
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I would agree to the idle adjustment if that will get you to 2K, but if you haven't started this engine, it may take some time to adjusted it.
That's time you don't have when breaking in a cam.
If it's loafing below that rpm mark it could damage the cam.
15 minutes minimum, make sure you have your cooling system good to go, Thermostat is not in backward (seen it), and run a fan at the front of the grill.
Don't worry about code right now.
I would put it off till I had capable help.
Remember the carpenter's creed: Measure 3 times, cut once.
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Okay, good news is I got it started up. Got 60lbs of oil pressure right away. I was able to get somewhere between 10 and 15 minutes of runtime at 2,000 rpm.
The problem we kept running into was it’s getting too hot. I had to shut it down a few times during break-in which sucks. But cooking the engine isn’t any better for it.
My thought is, it’s probably getting too hot because the new radiator & elecric fans probably struggle a bit to keep it cool when it’s sitting still and revved up. Also, engines run a bit hotter during break-in right?
Also, I was having trouble setting the static timing with it being revved up. That could be a factor too?
I’m not sure what’s going on with the ECM though. It’s throwing the SES light but when I checked for codes, it’s just showing 12.
If I remember correctly, it always shows 12 when in diagnostic mode right? Why would the light be on if there’s no codes stored?
I’m concerned there may be a sensor issue that could causing it to run lean or something.
Thanks in advance for any help!
I’m going to start it tomorrow again and while it’s at idle, set the timing properly to rule that out.
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Started it again today. This time I tried to set the timing to around 20 degrees while it was at 2,000 rpm. It was a lot happier and didn’t get much hotter than 205 before I saw the need hold there and move back and forth a tiny bit. Check engine light was still on with no codes...
I’ll update again if I can get that figured out.
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That is Awesome man! Congrats!
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Another update: The check engine light had turned off but I noticed the injectors were dribbling badly instead of spraying because they o-rings were damaged when I put the TBI back together after the rebuild. It was running really rough at idle.
I rebuilt the TBI unit again and the injectors are now working properly. The truck is running great except now I'm getting a DTC code 21 for Throttle Position Sensor too high. This wasn't an issue before I pulled the TBI unit off yesterday to rebuild it again.
The thing is, I only took the injector pods apart. I didn't touch anything around the TPS. I plan to go through the troubleshooting guide for that here on the site. However, I just wanted to see if anyone had any quick suggestions that might be the issue. From what I've read, it could be broken wires near the sensor. I should note the sensor is brand new.
Thanks guys! After this I think it'll be good to go and I can start driving it again!
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Did you ever find out what the two ports on the underside of the manifold were for? and what did you do with them?
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Dan,
No I'm not sure what they would be used for. I just bought some tapered thread 3/4" plugs and plugged them up. I used some RTV on them and let it set for 24 hours. Unfortunately, I won't have any way to check on them other than watch for water on the dipstick and/or pull the manifold every few years or something. Seems pretty pointless to have those there.
I didn't see too much on the internet about those ports. No one else has really mentioned them. I put up a warning on Amazon in the reviews section to give others a heads-up about it.
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You should be ok with the Jegs reman.
2) Is it fair to say, block the exhaust ports for power? Unblock them for MPG?
Colder intake manifold = denser fuel+air mixture?
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Stewart,
These are just two holes in the bottom of the intake manifold where the coolant flows under the TBI. If left open, they just fill up the entire crankcase with coolant. I can't figure out what purpose they could serve or what you would thread into them. There's a photo of them above.
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What oil would you guys suggest I put in this thing after the break-in oil?
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Stewart,
These are just two holes in the bottom of the intake manifold where the coolant flows under the TBI. If left open, they just fill up the entire crankcase with coolant. I can't figure out what purpose they could serve or what you would thread into them. There's a photo of them above.
i meant those metal plates for the intake manifold/manifold gaskets.
i would recommend mobil one synthetic 5W-30
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Oh okay I see what you mean now. Thanks.
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i've run nothing but Mobil 1 syn in the 4.3 after breaking in with valvoline conventional.
Did you email 'Brock about the two holes?
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No. But I think I will. I'll post back with what they say.
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Had an issue with the TPS that I was able to sort out. Turned out I had ordered the wrong one. Everything is working great now. However, I noticed after the TBI rebuild, the injectors are very noisy now. They were audible before, but now they're loud enough to hear inside the cab. Should I be concerned about this? Does this mean there's an issue that could cause failure?
I changed out the o-rings, gaskets and fuel pressure regulator diaphragm as well as the little nylon washers that go on the fuel line fittings. I also changed the little screens that go over the injectors.
The first time I did the rebuild on it, I reassembled it incorrectly by having the injectors turned 90 degrees off from where they should be. I had to replace the o-rings and little screens again as they were slightly crushed.
The truck is running great. No issues performance wise. Just want to make sure this won't become a problem.