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'89 Trooper 3.1 Engine Swap

9K views 32 replies 4 participants last post by  Ed Mc. 
#1 Ā·
Hello All,

I have a 1989 Trooper LS with the 2.8L (217K miles) and the manual trans.
When we first bought it:



A little background:
My friends and I bought the trooper for $500 in July 2020 for the Rocky Mountain Rambler 500. Long story short, we had a ton of work to do and we spent a couple of months tinkering with it to get it running enough to take it on the 'rally race'. It made it nearly 300 miles through the race (more like a marathon) in one day and the engine 'seized' within a mile or two from the finish line. Despite the perfect opportunity to haul it to the junkyard, we fell in love with it and decided to giver a new heart.

After doing some research I found the Planet and all the helpful info on here that has led me to this point. I asked Ed Mc for his swap info to determine the feasibility of doing an engine swap ourselves, we have decided to storm ahead with the engine swap and figured now is a good time to start a swap thread.

So far we bought a 3.1L GM V6 out of a 1992 Pontiac Firebird (~140K miles). It's on an engine stand right now and we've performed a leak down test and no worse than ~15Psi.
Bought a throttle body injection unit off a 5.7L V8 to affix to the 2.8L Intake manifold (bore it out) then bolt to the 3.1L GM V6.

The first (of many) questions I have when I drill the starter holes on the 3.1L block will I be using the starter off the 3.1L or the 2.8L? Are they the same starter by chance?

Thanks in advance!!

 
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#2 Ā·
Hi, Matt, the Firebird/Camaro 3.1 and 3.4 engines have the same issue when swapping into a ZuZu with a GM 2.8 V6 - their starter is on the pssgr side, and the ZuZu 2.8 block has the starter on the driver's side (same configuration as a FWD GM 60-degree V6).

So, you're gonna drill the driver's side of the '92 Firebird 3.1, and use the Trooper 2.8 starter.

BTW did you see the info on the Rodney Dickman Fieros starter drilling "jig" kit? I'd highly recommend picking up this drilling jig, it'll save you tons of head-scratching, and guarantee the holes will be correct. I drilled mine by hand, with no jig or template, and believe me you really don't want to have to do that!!

http://rodneydickman.com/product_info.p ... cts_id=179

Save the starter shims from the old 2.8, you'll need to start with some sort of shim pack for starter mounting. Bolt up the ZuZu starter with shims, and pull the starter gear into the flywheel teeth (be sure to use the 2.8 flywheel!). Check to make sure the tooth engagement is just right; not too tight or too loose. Shim accordingly. It's far easier to do this with the engine out, than it is to be lying on your back under the rig, trying to get the shims in!
Chevy Small Block V8 shims are what's used here, and are available in shim packs at most auto parts stores, if you need them.

You'll want to pull the 3.1's timing cover and use the 2.8 cover instead. While you're in there, change out the timing set. At 140K+ miles, it's gonna be worn out and sloppy.

Also replace the timing damper. The damper rides inside the "vee" of the chain, and has rubber "slipper" blocks bonded to its metal frame. These rubber blocks will harden & degrade with heat, oil exposure, and age.

The blocks eventually will crack, and then delaminate from the frame, leaving the chain to ride metal-on-metal on the damper. Which leads to chain breakage! Exactly how I got my '90 LS after the timing chain busted. It's a cheap part and well-worth replacing.

Another tip, with the intake manifold removed, rotate the crankshaft and watch the action of the hydraulic lifters. Each lifter should be rotating as it follows the contour of the cam lobe. If the lifter doesn't rotate, it's SHOT. Usually that means the cam has problems as well, which will lead to excessive wear on the cam and a "flat" cam lobe. Not a good thing.

In that case, the Comp Cams "252" grind would be a great addition to your engine. Especially since you're already working on breathing improvements to the intake and TBI unit.

Here are links to the Full Kit, which includes cam, lifters, timing set, valve springs, retainers, locks, valve stem seals, etc. This cam does require performance springs due to the increased lift. You can buy the cam separately, and use early Z28 valve springs/retainers, but if you're refreshing the engine, the full kit is a good deal.

Here are some links:

https://www.compcams.com/high-energy-20 ... 4l-v6.html

A bit cheaper at Summit Racing: https://www.summitracing.com/parts/cca-k16-232-4

Cam alone: https://www.ebay.com/itm/Comp-Cams-16-2 ... 3324426327

These roller-tipped rocker arms have a higher-than-stock rocker ratio for increased lift/duration and work well with the "252" cam:

https://www.summitracing.com/parts/cca-rp1414-12

Don't forget a new transmission input shaft pilot bushing in the end of the crankshaft, if you have a manual transmission. Soak the Oilite bushing in engine oil overnight, and install with a suitably-sized socket or other installation tool. Lightly grease the input shaft of the trans with Lubriplate 101 or other lithium-based grease, prior to installation of the trans.

Be sure to replace the rear main seal, that's a trouble area which will require pulling the engine or trans to fix if it leaks later on.

There's a camshaft cover plate at the back of the block with a cork gasket that should be replaced. There are little metal rings that go over each screw, to keep from tightening the plate too hard onto the cork gasket. Watch out for those pesky buggers when you remove the cover, you don't want one falling into the cam hole. There is info in my swap package about this gasket, Read and Heed!

Check the freeze plugs for corrosion. There have been a few members here that had problems with leakers, and out goes the transmission again. Who needs that??

Use a 3.1 ZuZu Pickup clutch, the clutch for the 3.1 is larger in diameter and will better hold increases in power:

https://www.rockauto.com/en/catalog/isu ... h+kit,1993

The Exedy is OE-quality, top of the line. I did use a Sachs clutch on a "2.8-to-3.1 Stroker" build and it was a very nice clutch. My Nephew has the rig now and it's still running great, 16 years later. Check eBay for good deals on these.

Have your 2.8 flywheel surfaced if it's in good shape. You can't use the flywheel that came with the 3.1, different # of teeth among other issues.

The flywheel used on 3.1 ZuZu's is the same:

https://www.rockauto.com/en/catalog/isu ... wheel,5348

The Sachs flywheel is reasonably priced, and is marked with a "heart" which means it's a best-seller.

Be sure to put a drop of Loctite Blue on the threads of each cleaned & de-greased flywheel bolt, and torque to factory specs.

That's enough Information Overload for now; if you still have my swap info be sure to read the writeups I did on my 3.4 swap, it'll help...........ed
 
#3 Ā·
Hello Ed, thank you very much for the info thus far, it has been extremely helpful.

Since my last post I've cleaned up and degreased the exterior of the engine (as best I could) and started disassembling the 3.1L on the engine stand. The Smog pump assembly, entire firebird fuel delivery system, valve covers, distributor, alternator and intake manifold have been removed. For being nearly 3 decades old the valve train looked pretty good IMO. Just a minor amount of rust on the push rods where they ride on the guides and maybe some carbon buildup, but other than that no major gunk anywhere in there! I rotated the crankshaft around and all the lifters twisted to some degree or another so that's good.



I will be buying a complete engine gasket set, any recommendations on a brand or will one of the RockAuto engine gasket sets work just fine?
https://www.rockauto.com/en/catalog/pon ... +set,10392

Also, I noticed that the intake manifold gasket goes on top of and below the pushrods, thus the pushrods would have to be removed in order install the new gasket. Besides making sure each pushrod goes back in the exact same location as before, are there any other things I should do before, during and when reinstalling the pushrods/rockers? Since these are not adjustable rockers I won't need to set the valve lash right? Just reassemble and torque down the rockers?

Ed,
I did end up buying the Rodney Dickman's starter relocation kit and will order the Cloyes 90373S timing set (with the damper) to replace the old 3.1L timing set. I plan on using the old 2.8L flywheel unless something is really wrong with it. I'm not sure I want to drop the extra money on a new camshaft or camshaft, although the appeal is definitely there. I do have a video of the engine running from the previous owner and it seems to to idling very smoothly. Like you said, there was a lot of info in your post already, so I'll order some of those other little odds and ends after I've already pulled the old engine.

It seems like the next step is to pull the old 2.8L engine out of the Trooper and start swapping 2.8L parts onto the 3.1L. Besides taking a bunch of pictures, carefully labeling every wire and bolt that comes off the 2.8L and draining the fluids, is there anything else I need to do with the 2.8L while its still in the Trooper? Or are there any tips, tricks or order of operations to pulling the engine out?

Thanks in advance!!

Matt
 
#4 Ā·
Hi, Matt, you're making progress! There's a tool that you can use to pull the pushrods without disturbing the valve lash adjustment. It's a great time-saver and perfectly suited to what you're doing. Here's the info for the Lisle 48300 pushrod tool:

https://www.denlorstools.com/home/dt1/p ... _tool.html

Under $20 on eBay, this inexpensive tool will save you a lot of aggravation:

https://www.ebay.com/sch/i.html?_from=R ... 00&_sop=15

Note: be sure to keep track of where each pushrod goes. They should be exactly the same, but you never know, there could be slight variances that might affect valve lash.

I have some good tips for engine removal in my 3.4 swap info files, if you didn't already get that from me, send me a private mssg with your email address listed, and I'll forward the files to you.

A couple of tips that you'll find in the swap files are as follows:

1) drop the front differential bracket to gain clearance between the oil pan and front x-member. If you don't, you'll destroy the clutch pressure plate fingers on the way out. Not a big deal, because you're replacing the clutch, but you do need the extra clearance on the way back together. (2) large bolts on each side, going straight up into the frame, through rubber mounts with an inner metal spacer, bonded to the rubber. On my 3.4 LS swap, they came right out. Another engine build, the bolts were rusted to the metal spools and the bolts broke loose, but would only turn so far because of the rubber. I had to crank air pressure up to 150 psi and rattle the bolts for about 20 minutes, applying heat too, before they broke free. What fun!

2) when the engine is up on the hoist/winch, disconnected from the frame mounts; take the metal brackets off the engine. This will allow you to lower the engine further, and you'll be able to better access the bellhousing bolts on top.

More good tips in the files that you'll want to see, even though you're not putting a Hi-Po 3.4 in there! It'll still run much better than a stock 2.8, especially with bored intake/larger TBI, and exhaust improvements.

Cheers..........ed
 
#5 Ā·
mattdk said:
Since these are not adjustable rockers I won't need to set the valve lash right? Just reassemble and torque down the rockers
While Ed didn't specifically mention it (And he IS one of the GM V-6 experts), the valve train IS adjustable, so you don't want to just tighten those nuts (if you already loosened them). There are different techniques for adjusting them, I'll let Ed go through that. Enjoying seeing this thread. Dennis
 
#6 Ā·
Dennis has a good point. I just glossed over that part, I guess. You definitely would have to readjust valve lash if you disturb the rocker arm locknuts. The Lisle tool will keep you from having to do that.

BTW if you have already moved the locknuts, we can run through the procedure for getting the correct preload adjustment on the hydraulic lifters....ed
 
#7 Ā·
Thanks guys! Wow I'm glad I asked about the pushrods, that would've been a pain to get readjusted correctly. Luckily for me I haven't taken off or loosened any of the rocker arm bolts, so I definitely plan on ordering that pushrod tool and hopefully not worrying about the valve lash.

Although, I did notice that a couple of the rocker arms did rock slightly to the sides (opposite of the designed direction of rocker if that makes since), is that a concern? It wasn't loose over the pushrod or valve spring (If I remember correctly). Is it possible that there is no tension on that rocker when the valve is closed and its free to rock side to side? (I will investigate further on Sunday when I pull the 2.8L)

Matt
 
#8 Ā·
Update on the pulling the 2.8L of the trooper: the radiator has been pulled out and almost everything has been disconnected from the engine except for a single wire on the passenger side going down to the engine block (can't see what it goes to) and the starter. We can't figure out how to pull the starter out, does it have to come out to pull the engine? If so, what's the best way to get to it? From the top, through the wheel well or from underneath? I noticed the oil filter is sort of in the way of the starter, haven't pulled that yet either. Then we just need to find and unbolt the front diff bracket bolts to drop it out of the way and the engine should be ready to pull out!

On an earlier note, does any one have recommendations/thoughts on any of the RockAuto Engine Gasket sets for the 3.1L? I see brands like ITM Engine Components and Apex that are currently in stock, are these brands ok?
https://www.rockauto.com/en/catalog/pon ... +set,10392

Thanks in advance.

Matt
 
#9 Ā·
mattdk said:
Update on the pulling the 2.8L of the trooper: the radiator has been pulled out and almost everything has been disconnected from the engine except for a single wire on the passenger side going down to the engine block (can't see what it goes to) and the starter. We can't figure out how to pull the starter out, does it have to come out to pull the engine? If so, what's the best way to get to it? From the top, through the wheel well or from underneath? I noticed the oil filter is sort of in the way of the starter, haven't pulled that yet either. Then we just need to find and unbolt the front diff bracket bolts to drop it out of the way and the engine should be ready to pull out!

On an earlier note, does any one have recommendations/thoughts on any of the RockAuto Engine Gasket sets for the 3.1L? I see brands like ITM Engine Components and Apex that are currently in stock, are these brands ok?
https://www.rockauto.com/en/catalog/pon ... +set,10392

Thanks in advance.

Matt
Here's a Felpro gasket set on eBay for $58 shipped, you won't find a better deal than that:

https://www.ebay.com/itm/382501034138

The starter is held on by 2 bolts, if you look straight up from underneath you'll see them. I'm assuming you have the front end (at least) on jackstands on a level surface. Don't forget to get under there and pull the metal "half-moon" shield at the bottom of the transmission.

If you have all the wiring disconnected from the engine, the harness just "peels" back and out of the way. A single wire from the O2 sensor does continue from the engine harness on the pssgr side, and runs all the way over the top of the transmission to the driver's side, to the O2 sensor.

If you've disconnected the entire engine harness, that wire stays with the harness and the engine comes out sans harness. If you leave the harness on the engine when pulling, you have to disconnect the wire at the O2 sensor and pull it out of its retaining clips.

The engine oil should have been drained and oil filter long gone at this phase of engine removal, so time to do that if the filter's in the way. You might get a bit of residual oil out of the engine, just stuff a shop rag or paper towels in the filter adapter to keep the mess down. If the oil filter adapter is in the way, unbolt it from the block and get it outta there. One big bolt in the middle, be sure to save it, you'll need it later!

The Big Bolts stick straight up into the frame (2 per side). So look along the brackets that hold the front diff and axles assy to the frame, and look along the frame; where they intersect is where the bolts are gonna be.

Good Luck..........ed
 
#11 Ā·
FYI, if you haven't removed the bell housing to engine block bolts yet, I found the top two very hard to get to (on the 2.8 / 3.1). I found it much easier to unbolt the transmission mount bolts and raise the rear of the tranny which opens up the gap between the top back of the engine and the firewall (the heater core hoses and brass nipples were in the way). Dennis
 
#12 Ā·
The engine is out!

It took several hours across 2 days, but we finally got it out! We needed every bit of the advice y'all left above.

Jacking up the rear of the transmission definitely helped access the top 4 bellhousing bolts along the firewall, thanks Dennis.

Dropping the front diff was definitely necessary, but was a major pain since one of the four bolts did not want to come out and was hard to access. The diff only seemed to drop about 1" which didn't seem like enough since the oil pan kept hitting the front diff before the pressure plate could completely clear the trans input shaft. As a result, we ended up taking the pressure plate and clutch off the engine in order to clear the input shaft of the trans.

Is there a way to drop the front differential more than just pulling the 4 bolts/nuts out? Is it possible that the front skid plate is holding it up?

Side note:
Turns out the old engine (2.8L) isn't seized ... the crank does smoothly rotate through a few full rotations with a breaker bar. My best guess is that the day it 'seized' when we turned off the engine that final time to let it cool off, the engine had already overheated several times that day and at that moment the starter blew up. There were a few times that day where the coolant reservoir was boiling/bubbling violently and the engine was overheating which leads me to believe the head gaskets blew. I digress, but when I pulled the starter motor this past weekend some pieces came out of the end and all of it started to make sense on what could've happened that fateful day.

The next steps are to remove the 2.8L intake manifold have it bored out for the bigger TBI, replace the timing chain set and keep the swapping the 2.8L parts onto the 3.1L.

Matt
 

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#13 Ā·
WEEEEEE! Well that's the hardest part!

If you still had the back of the transmission jacked-up, that would of course make the top bellhousing bolts more accessible, but with the front of the transmission pushed-down, it might not have the clearance you need to get the trans input shaft to clear the clutch diaphragm fingers.

When I did mine, I didn't jack-up the rear of the trans or disconnect anything back there. I did drop the diff, and pull the motor mount brackets off the block, which did let the whole assembly drop down enough to get at the top bell housing bolts. Plus I went at some of them from underneath with long 1/2" extensions and an air wrench (once I had the bolts busted-loose enough to turn with the wrench).

Was also able to get the engine back in without jacking-up the rear. In fact I had a jack under the front of the trans to keep it from dropping too much, as the engine was pulled away from the trans. So maybe try a combination of all that to see what works the best when going back in.

I don't recall having the skid plate in place, either, when doing the swap. So that's a good thing to try, it comes off easily enough.

Sounds like you may have a decent 2.8 core, that's a good thing! Easily rebuildable to 3.1 specs, or with a .030" or .040" overbore, approx 3.2L in displacement. You could build a pretty nice performance engine out of that. For your next Trooper!! :twisted:

And no starter relocation required, it's already there!

Press on Smartly, the fun part commences!............ed :mrgreen:
 
#14 Ā·
Ed Mc. said:
WEEEEEE! Well that's the hardest part!

If you still had the back of the transmission jacked-up, that would of course make the top bellhousing bolts more accessible, but with the front of the transmission pushed-down, it might not have the clearance you need to get the trans input shaft to clear the clutch diaphragm fingers.

When I did mine, I didn't jack-up the rear of the trans or disconnect anything back there. I did drop the diff, and pull the motor mount brackets off the block, which did let the whole assembly drop down enough to get at the top bell housing bolts. Plus I went at some of them from underneath with long 1/2" extensions and an air wrench (once I had the bolts busted-loose enough to turn with the wrench).

Was also able to get the engine back in without jacking-up the rear. In fact I had a jack under the front of the trans to keep it from dropping too much, as the engine was pulled away from the trans. So maybe try a combination of all that to see what works the best when going back in.

I don't recall having the skid plate in place, either, when doing the swap. So that's a good thing to try, it comes off easily enough.

Sounds like you may have a decent 2.8 core, that's a good thing! Easily rebuildable to 3.1 specs, or with a .030" or .040" overbore, approx 3.2L in displacement. You could build a pretty nice performance engine out of that. For your next Trooper!! :twisted:

And no starter relocation required, it's already there!

Press on Smartly, the fun part commences!............ed :mrgreen:
Ed, I forgot we did pull the motor mounts and lower the engine down and it helped a ton in gaining access to those upper bellhousing bolts. I think removing that front skid plate will help drop that diff even more when we drop the 3.1L in.

The Intake manifold and TBI is at the machine shop now getting the holes bored out and the other little things done to the bigger TBI. After re-reading Eds Swap Files and some zuzu threads, I'm thinking we will swap the 2.8 injectors into the larger TBI and do GeoffinBC's adjustable fuel pressure regulator hack to help get more fuel in the engine. Thoughts? It seems like most 4.3 injectors are $50-$100 each :shock: .
It seems like some people do 2.8 injectors and maybe a 3.1L ECU and most people do the bigger 4.3 injectors, but since we have the 3.1L engine instead of the 3.4L and we are on a bit of a budget, I figure this is the way to go.

On another note, I purchased a Melling M134 oil pump and the Melling 245S Oil pickup tube and the kit says it doesn't come with a gasket for the oil pump, is there a gasket or O-ring that needs to go with it?
Also, I've read in multiple places that you really shouldn't put the oil pump in a vise and hammer in the pickup tube into it. Is there any way to install that pickup tube without the special tool?

Do I need to swap over the Troopers 2.8L Exhaust Manifolds or can I just use the ones that came on the Firebirds 3.1L?

Thanks in Advance!

Matt
 
#15 Ā·
mattdk said:
Ed, I forgot we did pull the motor mounts and lower the engine down and it helped a ton in gaining access to those upper bellhousing bolts. I think removing that front skid plate will help drop that diff even more when we drop the 3.1L in.

The Intake manifold and TBI is at the machine shop now getting the holes bored out and the other little things done to the bigger TBI. After re-reading Eds Swap Files and some zuzu threads, I'm thinking we will swap the 2.8 injectors into the larger TBI and do GeoffinBC's adjustable fuel pressure regulator hack to help get more fuel in the engine. Thoughts? It seems like most 4.3 injectors are $50-$100 each :shock: .
It seems like some people do 2.8 injectors and maybe a 3.1L ECU and most people do the bigger 4.3 injectors, but since we have the 3.1L engine instead of the 3.4L and we are on a bit of a budget, I figure this is the way to go.

On another note, I purchased a Melling M134 oil pump and the Melling 245S Oil pickup tube and the kit says it doesn't come with a gasket for the oil pump, is there a gasket or O-ring that needs to go with it?
Also, I've read in multiple places that you really shouldn't put the oil pump in a vise and hammer in the pickup tube into it. Is there any way to install that pickup tube without the special tool?

Do I need to swap over the Troopers 2.8L Exhaust Manifolds or can I just use the ones that came on the Firebirds 3.1L?

Thanks in Advance!

Matt
Matt, you can do the F.P.R. mod which should give you enough pressure increase. It worked well on an '89 3.2 "Stroker" build I did back in 2006. Usually the 4.3 injectors would be too rich for a 3.1, and you might have to lower fuel pressure to get them in a "happy" range. Plus as you said they're not cheap!

Another inexpensive and simple way to jack up the fuel pressure is to use a stiffer spring in the fuel pressure regulator. This one will give you 14 psi which should be plenty:

https://www.amazon.com/Throttle-Body-Sh ... B012U3MMEG

On the 3.1 Pontiac exhaust manifolds, they of course have the same bolt pattern as the ones used in the ZuZu 2.8 (which BTW are the same ones used on S10 2.8 applications). However, the position of the exhaust dump on the 3.1 manifolds might not be the same, and if so, they won't line up with the ZuZu exhaust system's downpipes. So that's something to check. If they look identical, then you're probably OK.

I would still pull the manifolds, checking for busted bolts (very common) along the way, and installing new manifold gaskets (Remflex is highly recommended; Geoff uses them on his engine). Put some anti-seize compound on the bolt threads and you'll never have a stuck bolt if you need to pull the manifold in the future.

On the oil pump, it probably doesn't have a gasket between the pump cover and pump body. As I recall, I used some anaerobic sealer there (Loctite/Permatex 518) just for good measure. You'd never want to use RTV because anything that squishes out internally, will harden and circulate thru the oiling system. Bad News. The anaerobic stuff only cures at the joint; the rest just harmlessly washes away.

IIRC there's a thin gasket where the pump bolts up to the block, but it's been so long I can't recall for sure. If so, it would be in a gasket kit, not supplied with the pump.

And I do recall putting my oil pump in a vise, but I clamped down on the body, which is one solid piece of metal. You certainly could crush the pump body if you put that part in the vise! Or, you could mount the pump to the block and that probably would be secure enough to be able to tap drive the pump screen home. You can do the job without the special tool, but it's so much easier with. Autozone should have it to rent for free (with full-price deposit, refunded upon return of the tool). It might help to freeze the pickup overnight in the fridge.

I used Red Loctite 571 to secure my pickup tube to the 3.4's pump; 19 years later it hasn't fallen out! You can also have the tube tack-welded to the pump cover to keep it from moving. Be sure you check fitment of the tube to the oil pan, it's easy to get the tube misaligned and then the pickup screen hits the pan or bottoms out and won't pick up oil.

HTH & keep up the good work!.........ed
 
#16 Ā·
Awesome, I will proceed with the 2.8 injectors and the FPR mod and go from there, I will keep that spring information/link on the backburner if I need it.

I did a quick visual check on the exhaust manifolds of both engines and they looked very similar, so if they are different it won't be by much I imagine. I have to remove the manifolds from the 3.1 anyways so I can replace the head gaskets, so I will check then.
The Fel-Pro engine gasket set that I bought has exhaust manifold gaskets, so I will probably just use those (Noted that Remflex is recommended).

I couldn't find anywhere that rents the oil screen installation tool (but they sell it for $97 at one of the auto stores :shock: ). I purchased a two piece 3/4" shaft collar to hold the screen/tube while the pump is lightly tapped into place.
https://www.amazon.com/Climax-2C-125-Tw ... 1692&psc=1

I plan to use red loctitie on it to keep it from moving. Call me crazy, but I feel like it would be so much easier if they sold the pump with the screen/pickup tube already pressed in, but I guess that would defeat the purpose of getting it to the right height in relation to the oil pan.

If anyone else knows if there is a gasket between the block and the oil pump, let me know. Otherwise I'll continue my research and hope that one isn't needed :lol: .

Matt
 
#17 Ā· (Edited)
An update thus far:

Old 2.8L oil pan was cleaned and we used RTV Black on both sides of the oil pan gasket to seal it up. The old sloppy timing set was replaced with a brand new set, glad I did that. Replaced the seal in the 2.8L timing cover, cleaned it up, RTV black on both sides of the gasket and installed it. Installed a new water pump, reused the 3.1L harmonic balancer, replaced the cork gasket for the camshaft housing and replaced the rear main seal. Installed a new head gasket with new head bolts, I used Permatex no. 2 on the end of the threads to seal them since the bolts were in coolant passages. Had the intake manifold bored out for the bigger TBI, installed the intake manifold with new gaskets and RTV Red High Temp Sealer on the middle front and rear S-shape portions. Removed the 3.1L pushrods, cleaned them up inside and out reused them. Ground off the extra motor mount on the drivers side of the block to affix the oil filter adapter with a new gasket and RTV.
Poured in some oil, installed the oil filter, primed the oil pump with the hex shaft (underneath where the distributor is) with a long extension and a drill. Made sure oil was flowing through every lifter and pushrod.

The oil pump pickup tube installation is a PITA:
We installed the oil pump (without a gasket or sealer), set the pickup tube height and smacked in the pickup tube and boy...getting that pickup tube into the pump was quite the effort! I placed the pump in a vise, I used a shaft collar to mount to the tube by the flaring, an angle iron to help pound in the tube and used a mallet to smack it in. I used a little red loctite right before the flange on the tube was fully seated. I'd imagine the pickup tube would stay in the pump just by how tight fitting it was getting it in there.

Whew!

Now for some questions moving forward:

We need to replace the slave cylinder; would that be easier to do with the engine out or can it be done with the engine in?

Since we are using the 2.8L oil pan, we can just use the 2.8L dipstick as well, correct? We don't need to switch the dipstick tubes along with the dipstick right? (It seemed nearly impossible to remove the old dipstick tube)

We seemed to have lost the starter mounting bolts, does anybody have any idea what size and length they are?

I've heard the valve covers are known to leak oil, what is the best way to seal it up besides buying the fiero valve covers?

In terms of relocating the knock sensor on the passenger side of the engine, all the directions say to move it to the lower most rear plug/hole, but on my 3.1L its already in that position. Am I missing something or are some engines already in that same hole?

Thanks in advance.

Matt
 

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#18 Ā·
Matt, you've been busy!!

I'll just paste your questions in, and that'll make it easy to answer:

Now for some questions moving forward:

We need to replace the slave cylinder; would that be easier to do with the engine out or can it be done with the engine in?

Probably easier to get at with the engine out, but entirely do-able with everything intact. Your choice.

Since we are using the 2.8L oil pan, we can just use the 2.8L dipstick as well, correct? We don't need to switch the dipstick tubes along with the dipstick right? (It seemed nearly impossible to remove the old dipstick tube)

Yup, use the dipstick that came with your 2.8's oil pan.

We seemed to have lost the starter mounting bolts, does anybody have any idea what size and length they are?

I don't see any listed at Rockauto.com AFAIK they should be the same as any 3100/3400 GM FWD V6. In fact the later model FWD starters with gear reduction fit the 2.8 as well, since it's mounted in a FWD configuration. I looked up a 2000 Lumina 3.1, and GM P/N 11610633 for the long bolt (which is 10mm x 1.50mm thread pitch, 120 mm long):

https://www.rockauto.com/en/moreinfo.ph ... 53&jsn=616

The Dlr might carry the short starter bolt, too. Or I'd imagine you can find a high-strength 10mm bolt at Fastenal or other local specialty store. I would definitely get the factory long bolt, since it's a body-fit and will help align the starter. Be sure to check the starter gear's teeth engagement with the flywheel and use shims between the block and starter as needed. You don't want the fit too loose, or too tight. Too tight and the gear will bind and not kick out after the engine starts; too loose and you're gonna grind teeth. Most auto parts stores carry a shim kit for Small Block Chevy V8's and the same style shims are used on the V6 starter.


I've heard the valve covers are known to leak oil, what is the best way to seal it up besides buying the fiero valve covers?

Make sure the flanges on the valve covers aren't all bent up. You can straighten if they are. Use a quality valve cover gasket and they won't leak. Mine are Fel-Pro and I had a big problem with sealing because I used some poor quality chrome valve covers; but with the standard cover, a straight sealing surface, the Fel-Pro rubber/cork gasket set (inexpensive), and a thin layer of Permatex Ultra Grey RTV on the gasket, it shouldn't leak.

In terms of relocating the knock sensor on the passenger side of the engine, all the directions say to move it to the lower most rear plug/hole, but on my 3.1L its already in that position. Am I missing something or are some engines already in that same hole?

On a RWD block, the starter is in the way and GM puts the knock sensor in the most forward hole; but with an engine in FWD configuration, it's easier to use the hole at the rear of the block, since there's nothing in the way there. Not that there's a lot in the way doing it the other way, but since it's under the exhaust manifold, the factory probably would install it 1st, before the manifold is bolted up.

At any rate, you lucked out, you don't have to do anything!
:mrgreen:

Hope that helps. Keep up the Good Work!........ed
 
#19 Ā·
Huge update!

The engine is in, the engine is hooked up and the engine is runningā€¦barely.

(Section titles are bolded if you donā€™t want to read the whole thing)

Engine Installation:
Getting the engine in the trooper, aligned and bolted to the transmission was about as dreadfully difficult and time consuming as I expected. Things we had to do to get it in:
Unbolt and drop the front differential (already done when the old engine was extracted)
Remove the front skid plate
Remove the crossmember underneath the front driveshaft/differential
Ratchet strap the front diff towards the front of the vehicle
Unbolt the transmission mounts
Remove the rear driveshaft (donā€™t know if this was totally necessary, but helped in seating the shaft in the engine)
Even with all that done we still needed another Ā½ā€ to clear the transmission input shaft from the pressure plate fingers. Without being able to gain anymore clearance, we just depressed a pressure plate finger to get the input shaft inside of the pressure plate. Once everything was aligned, we snugged up the bellhousing bolts slowly all around, bolted in the motor mounts and the engine was in! WHEW!
Note: we had to use longer bolts for the lowest bellhousing bolt on each side (2 longer bolts total, all the others were reused) and you have to put the half-moon shield and starter on after the engine is bolted in.
Once we had all the accessories bolted on, wiring harness attached, new cooling system in, fluids filled up and the starter hooked up correctly, it started up and idled FIRST TRY!

Then everything from that point on went downhillā€¦

What happened between first startup and where we are at today:
We drove it around the block a couple times and the engine would want to hesitate and bog down unless the revs were kept up and you didnā€™t stab the throttle, but otherwise drove well enough to bring it down to our ā€œraceā€. Trailered it to the Rocky Mountain Rambler 500, managed to drive it 16 miles on our way to the check-in for the race (topping out at 10,300ft!) and we finally had to pull over 3 miles from check-in and it didnā€™t want to start again that weekend. On the uphill portion of the journey, it had some pretty wild surging going on unless I kept the revs up high and on the downhill, I could barely keep it from dying. Since then, it has not been able to drive under its own power. It currently is sitting in front of my house while I tinker with it for an hour or so every few days.

Engine upgrades/alterations:
Bored out the Intake manifold for the bigger TBI throttle plates
Bigger TBI unit out of at GM 305 V8
14 Psi fuel pressure spring (still using the 2.8L injectors)
Removed the Smog equipment and plugged the hole in the exhaust

The current situation:
When I turn the ignition on the check engine light comes on (but wonā€™t read me any code besides the usual 12 code) then when I start the trooper it starts up great and idles decently at about 800-900 rpm. When I rev it up it only hesitates and/or bogs down when I really stab the throttle and when doing so the check engine light flashes but goes away. Sometimes fire briefly spits out of the throttle body after the throttle is briefly floored. Whenever I try and drive forward (manual transmission) it hesitates, RPMs drop, CEL flashes and the engine stalls or nearly stalls. When I try and drive in reverse, it has no hesitation no CEL and drives fine.
Side note: after only 16 miles and a several hours idling, the engine oil is medium brown/grey colored (not quite milky) and has some very fine metal shavings in it. Yikes.

Things Iā€™ve done since it drove last:
Replaced the TPS and IAC with the ones from the trooper (the TPS that was on the new TBI was not reading voltage at any throttle position)
Replaced the coolant temp sensor and sender
Set the minimum air, idle and adjusted the TPS voltage (took a while to find the correct procedure on this)
Adjusted the timing to 14 degrees with the engine warmed up, at idle, and timing advance
Adjusted the throttle cable so the throttle plates sit even (not slightly cracked open as it was initially)
Pulled out the EGR, spark plugs and O2 Sensor and cleaned with carb cleaner (all had a decent amount of carbon build up) and reinstalled
Checked the fuel pressure going into the TBI and itā€™s reading a steady 13 PSI at idle and while revving up, Injectors donā€™t seem to be leaking and are spraying with an even cone of fuel

Final thoughts:
I think it might be running a little bit rich and/or the O2 sensor is bad, probably also has a minor vacuum leak somewhere. Don't know when/if it is switching in and out of open/closed loop.
Was thinking about doing the heated O2 sensor mod, changing the oil and filter, replacing all the vacuum lines, putting in the original 2.8L TBI fuel pressure spring. I've read countless threads on the idling/hesitation issue on these engines and I'm not totally sure what the next step is.

Thanks in advance.

Matt
 
#20 Ā·
So, I rechecked the TPS voltage and it was at 0.35V with throttle closed so I adjusted it back to ~0.5V, started it up and idled alright, but still stalled out when I tried driving away. Then while messing with some other stuff I guess I left the TPS disconnected with the ignition on and now it reads 0V with the throttle plates closed, spikes up in voltage when I open the throttle plates and then goes back down to zero volts. Tried to see if it would idle and it doesn't hold idle and dies out. Tried disconnecting the negative end of the battery to see if it would reset and it is still the same.

So I ordered a new TPS sensor along with new vacuum hosing, ACDelco Heated O2 Sensor and 3 wire weatherpack connectors (male and female). I'm going to install the new TPS sensor and reset the voltage and install new vacuum hoses to start then eventually get to the O2 Sensor. Really don't know where to go after that.

Anybody have any more thoughts on what could be happening??

Is there a way to reset the CEL, I thought I read about disconnecting both battery leads and holding them together for 10 seconds to reset the ECM? (don't remember where I read it so I won't try it unless it someone can verify)

Matt
 
#21 Ā·
Matt, if you disconnect the battery for more than 60 seconds, the ECM should clear any trouble codes set.

Get the min idle speed (with IAC disabled) as close to 750rpm as you can. My 3.4 was really fussy until I got the idle speed and TPS voltage set to a Gnat's Ar$e. As close to .5V as you can.

It's possible the MAP sensor could be damaged from backfiring, so you should probably check that out.

Here's some good info on that:


Also make sure the timing was adjusted with the ESC wire in the console unplugged from itself. The black wires with white stripe and a white connector. See attached pic. Note that the ALDL wires (white with blue stripe) are normally disconnected unless you're running a diagnostic or doing the IAC/TPS procedure to drive the IAC pintle all the way in. The other way to put the ECM in diagnostic mode is to jumper together the 2 pins in the corner of the ALDL plug.

How's the injector fuel spray look? With a 14psi spring, you should have more than enough fuel to make a stock 3.1 happy. Definitely check all the vacuum lines, a leak somewhere will mess things up royally.

Any more issues with the engine oil? That sounded scary.

Hand Motor vehicle Automotive tire Hood Gesture
 
#22 Ā· (Edited)
Thank you as always Ed. I will dial in the idle and TPS voltage as best as I can with the new TPS sensor (it might help if I had another person to help me unlike last time šŸ˜‚) and I'm going to test the MAP sensor too. My vacuum pump just broke so ill have to grab another one at harbor freight. I did set the timing with that white ESC plug undone and I have identified the ALDL plug as well.

One thing I keep reading is that the timing and idle adjustments should be done with the engine warmed up and in closed loop. How am I supposed to know the engine is in closed loop besides seeing the coolant temp gauge hold steady in the middle of the readout?

Video of the engine reving up from idle and then stalling out when I try to accelerate:


Also, the injector spray seems pretty conical and even; I can see it pulsing and it does sputter a little after quickly opening the throttle. Although, it does looks like there might be excess fuel spraying from the injectors and it does occasionally spit fire out of the throttle body after opening the throttle abruptly. So maybe there is too much fuel? I've already checked the fuel pressure going into the throttle body and it measured an even 13psi (figured it should be 14psi..).

Video of the Injector spray and backfire:


Yeah I was planning on changing the engine oil and hoping it didn't turn creamy again, hopefully it is just a little bit of excess moisture and metal shavings in the engine from when we initially tore the engine down.

Thanks in advance.

Matt

Added a ton more photos to the thread!
 
#23 Ā·
Yeah, that's pretty strange how the Check Engine light comes on instantly when you give it some throttle. I'd say about the only things that could make it do that are TPS and MAP sensors. Nothing else on the 2.8 TBI system would respond that fast.

If you can't get it in Closed Loop to adjust timing, at least if it's warmed-up you can still get it done. But you do need to disconnect that ESC wire in the console, or you don't know what the setting is. Most times it's impossible to read the timing scale if Electronic Spark Control is disabled.

I think you'll find an issue with one of the sensors. Otherwise maybe the ECM's screwy. I'd definitely pull the trouble codes out and see what's happening.
 
#24 Ā·
Figured it out...

The trooper lives again...

The ECM ground wire that goes to the engine block was loose.

There is not the same ground location on the 3.1L engine block as there is on the 2.8L (See picture). We used an oil pan stud to ground to and the nut must've came loose after the first 16 mile drive, giving us a weak/intermittent ground to the ECM. I tightened up the nut and it drives around great! I will definitely need to find a much more suitable ground location moving forward.

Now that the ECM is grounded correctly, we drove it around town a bit and the engine eventually threw codes 13 and 33 (O2 Sensor and MAP Sensor, voltage high). I was already planning on converting to the heated O2 Sensor, but I was reading Geoffinbc's heated sensor how-to document and wondered what the best 12v switched positive lead (hot in run) would be on the trooper? Could I use something out out of the fuse block?

The Heated O2 Sensor How-To:
https://9839f16c-3fad-4d37-89f6-38d...d/a62d6a_c81bf44980dc43159cdb64da7f582da0.pdf

Thanks in advance.

Matt
 

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#25 Ā·
Yeah, that's a big ol' mess of ECM and engine control ground wires in one lug, that will cause a lot of pain if it's not connected or loose. Ask me how I know! When I did the engine swap I had pushed those wires into the fender well, out of the way. Took a while to figure out where to put them.

The 2.8 had a bolt hole in the pssgr's side of the block where you could fasten the ground wires. I used the crank sensor bolt on the 3.4 to do the same thing. If you can find a solid grounding point right on the block, it would be a better & more reliable connection than on the oil pan.

As I recall on the heated O2 sensor, there was a suggestion to tie into the power windows circuit at the fuse block. If your rig doesn't have power windows, then you could hook right into the empty PW relay socket. It's a high-amp, switched source of power. The heated sensor doesn't draw a lot, at any rate. I have mine all installed and the "hot" wire run up to the engine compt, haven't figured out what to hook it too yet. My LS has power windows. Will just have to find a convenient source of switched +12VDC and splice it in.

If the engine is running well, and the MAP sensor tests out, I'd ignore it. I get an occasional "check engine" light with EGR code on my 3.4. Probably 'cause the 2.8 computer is expecting a certain amount of exhaust flow/change of exhaust mixture when it opens the EGR valve when driving down the road to test how it's working. When the light goes on, if I turn the ign off then on again the light goes away. Just an irritation, it's not affecting how it runs.

Anyway, glad you finally got to the root of the problem. Now you can concentrate on other things!
 
#26 Ā·
Yeah it was quite the discovery! I was dumbfounded when I figured out that was source of the problem. Anyways, I found a solid location for the ground wire, ended up using small bolt on the underside of the passenger side motor mount. Cleaned up/removed the paint off of the mount surface, bolt, ground washer at the end of the wire, and used battery terminal grease. Should be much better now.

I'll see if I can wire the positive 12V power lead for the O2 sensor into the power windows circuit (the trooper does have power windows).

Changed the oil and it looked absolutely terrible. It was a light milky brown/grey colored. I saw a lot of fine metal shavings in the oil and I'm pretty sure it was in there because of the metal work we (stupidly) did with the intake manifold off. At least, that's what I'm hoping its from. IIRC the oil that was in the 3.1L when we got it was not milky nor had any metal shavings in it, just dark oil. Fingers crossed it doesn't look like that again. Could coolant be leaking into the oil around the intake manifold gasket? I'm not too confident that was put on as well as it could've been. Is it common to have a leaky intake manifold?

I need to get the trooper registered and plated, and in my county I need to pass emissions, but the trooper didn't have a muffler when we bought it. About a 3ft section of exhaust is rusted out between the catalytic converter and the tail pipe; its almost as if the muffler rusted right off at some point šŸ˜‚. I feel like this is a good time to upgrade to the larger free flowing exhaust if its not too much $$$. Given my current setup (3.1L, bored Intake and larger TBI), should I get a 2" or 2.25" diameter exhaust?
Do I need to replace everything up to the headers including the y-pipe or can I just replace the catalytic converter and do a cat-back exhaust?
I'm going to take it to a muffler shop, but I need to know what tp tell them to replace.
Recommendations on a budget free flowing cat and muffler?

Thanks in advance

Matt
 
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