GT block Interchangeable with the S4 block
 

Rebuilding my 1988 S4 engine . Can I use a 1989 GT block? Also where on the block is the block type imprinted? Thanks a lot.

Motor ID is stamped into a flat spot at the top front of the block, look straight down from the upper hose to the radiator and you should see it, something like M28/44 and serial number.

89 GT is a rare car, the block could have some value to a numbers correct owner. You might want to consider selling it. I think it should work though.

Thanks for the information.

can you please add more info about what your doing?
Why use a GT block what happened to the S4 block?
The girdle of each block is machined to each block.
so these parts must be kept together.
Piston assemblies must also be of the correct tolerance group,
stamped above each bore 1,2,3

My engine has locked up. I suspect the thrust bearing only because I inspected the flex plate and it was bent forward. I have not torn into it yet. What I have read is that the block and crankshaft becomes scored and unrepairable. I am also looking for a complete engine.

if you had thrust bearing failure then the whole engine is now contaminated with metal as well as the oil cooler. If so then the valve tappets should be replaced unless you can take them apart , the cam journals may also be scored so new heads may be needed .
A complete engine would probably be the best course of action to repair the car also flush out or replace the oil cooler.

The oil can be checked by getting a sample of the oil dripping it onto a black piece of cardboard,
then looking at the oil in the sun you will see lots of metallic particles , if so then you can figure thrust bearing failure

drain plug should have flakes of steel all over it. Oil filter too.

Actually, are not flakes of aluminum? In my very limited experience with 2 failed engines the flakes were all aluminum....didn't find any steel flakes at all....:D

First step, find out what is actually wrong with the engine.

I want to thank everybody for their help. There is a lot of insightful information. I will start with the oil. I do not know the history of this car, but looks like a fun project especially with all the help. Thanks and I will keep on posting with my progress.

I just completed the knuckle busting part of your project. I'm now into the head scratching, hair pulling part of "why the !@#$$ won't start. Slowly eliminating possible reasons.

Give us additional symptoms and what you have done so far. There are some really smart folk on this forum that might be able to give you guidance.

can the engine be turned by hand?
do the timing marks line up?
Are there metallic specs in the oil?

I am in the process of removing the engine from the car. I cannot turn the motor over at all. I drained the oil and could not see any metal. The oil was pretty thick. I purchased the car knowing the engine did not turn but the former owner did not know what happened except it stopped running. I will have the motor out by this weekend and plan on looking in the oil pan first or is there any suggestions on the sequence I should take on investigating the problem. All this help is appreciated.

Could be a dropped valve: keeping it to rotating: try rotating it a wee-bit backwards.

Also is the engine disconnected from the drivetrain?

Mark

Yes I have separated it. There are only 8 bolts left to bring it out. The engine mount bolts. I do not get home until after dark so I am going to wait until Sat. I will try that. Over the last 2 weeks I was thinking maybe the pistons might be frozen so I poured some transmisson fluid to break it up. No luck yet.

By the way I am still looking for a short block or an entire engine. The GT block was not a GT block. It was an S4. By the time I was ready to buy someone else bought it. Oh well.

Last night I tried to rotate counterclockwise. It is frozen in both directions. This weekend I will pull the engine and look inside. I am very curious what is locking it up. I will post with my findings.

Locked up might not be so bad, whats the history?

The DMV often shows 89 to 91 as S4 GT which can confuse people, but a GT motor is worth twice or more what a S4 is.

The car is a 1988 S4. Engine is a 5.0L 32v M28/42. I purchased the car from someone who does not have any records and could not tell me what happened. I believe he bought it and then just turned around and resold it.

Should I take the heads off first or work below and open up the oil pan. I have the engine 99% out. I just have the eight motor mount bolts left to remove. Thanks.

After the motor is out of the car, I would first drop the pan. You should be able to immediately know if the engine has TBF (thrust bearing failure). If it does, the engine is toast. If it does not have TBF then the next logical suspects are failed main bearing in engine, or frozen piston(s) due to head gasket failure.

I would bet on TBF as you mentioned sometime back that the flexplate was considerably depressed....

If the bottom of the block shows no signs of TBF and you have no frozen main bearings then the next step would be to pull the heads....

Pulling the engine this weekend. Thanks.

Example of TBF
 

Here is a photo of a TBF block web "machined away" by the crank counterweights when the thrust bearing fails...http://forums.pelicanparts.com/uploa...1328284438.jpg

Have you drained the engine from coolant? If headgasket failure due to overheating, could have hydrolocked the engine. Once drained, the rings will rust & the resistance will keep the engine from easily turning over. Doing what you're doing is best: remove & investigate from the underside.

A friend had a boat engine (although cast-iron block), took a few weeks of soaking the cylinders with PB blast to finally free it: was fine & dandy. :)

Does TBF affect ALL YEARS with automatic?

If the head gasket failed and the engine has coolant down in the cylinders locking it up, there is also a good chance of serious damage. The following photos are from an '88 Don Carter picked up last monthhttp://forums.pelicanparts.com/uploa...1328286441.jpg
http://forums.pelicanparts.com/uploa...1328286455.jpg

A solution for this sort of damage is not easy...how expensive remains to be seen.

And to the other question George just asked, do all autos risk TBF? I think the answer is a qualified yes. I think the higher torque later models are more prone to it, far more examples have occurred with the later cars. But, IMO, the same flexing occurs in any auto, and unless the clamp has the circlip in it, it can move forward and exert pressure on the flex plate. By the way, none of the autos I have looked at had the circlip...and those go from 82 thru 89....

Early AT had a clip or something that prevented migration on the torque shaft, but I'm not sure when the change occurred, maybe 3 spd to 4 spd or around that time.

When the thrust bearing going several bad things happen;

Machined bits of metal go all over in the motor.
The bearing area overheats and cracks the block web.

How do you post pictures?

Make sure the image isn't monster big, like uncompressed camera picts.

Start a reply in the little box at end of thread, type a bit, click the go advanced. New page should show a "Attach a photo" box below the text entry box. Rest is follow the directions.

http://forums.pelicanparts.com/uploa...1328344389.jpg

Well here we go!!! Could not wait until Sat. to pull the engine. Started Friday night at around 6:00pm.http://forums.pelicanparts.com/uploa...1328364964.jpg


At 7:15 its out. Had a little trouble with the engine wanting to let go of the bell housing. But once released it wiggled out nicely. Not much room!! I ran out of head room with the boom and the garage door. Had to lower the car and work the door up and down to move the boom around. http://forums.pelicanparts.com/uploa...1328365340.jpg

Neighbor came over after it was out and we enjoyed a drink.

My next move is to mount on an engine stand and start with the oil pan to see whats up.

I am guessing you have noticed these engines are pretty heavy and do not lend themselves to the usual el-cheapo stands? They tend to fall over easily, the center of gravity is high, and the 3 wheel engine stands are really risky.

I was able to modify one by adding bracing and adding 2 wheels on a "front outrigger" to keep it under control. After the fact I concluded that maybe the more expensive 2000 pound HF stand made sense....neither the 750 pound stand nor the 1000 pound stand they sell are up to the 928 engine without some re-engineering like I mentioned above

I've used the 1000 lb H base stand without any trouble, but keep in mind NONE of the stands recommend moving them with an engine mounted. You are supposed to do all moving with the cherry picker.

BTW hint on the cherry picker, keep the length of all the chains to a minimum.

I tried to bring the chains close to the engine. I could not turn the adjuster because of the chain was in the way. So, I had to extend it.

I opened the oil pan and take a look.http://forums.pelicanparts.com/uploa...1328407248.jpg


Well, that looks like bad news.

I have also took the cover off. How does that look. How do you determine whether the heads are good?

For some reason I am not able to download the cam picture

Now?

http://forums.pelicanparts.com/uploa...1328409377.jpg

Both the Heads and Block look real clean.

That sucks. You would think Porsche would have stood behind such an expensive car and issued a recall.
Also hard to believe there was never a class action considering how many of these cars were probably owned by lawyers.

Is it possible to clean the hydraulic lifters. If so, how do you do it?

I'm not sure whats in the picture is a smoking gun, I believe all blocks have some machine work in that area.

What was in the pan?

What is the crank endplay?

The damage shown in the photo is very typical TBF. The "machined surface" on the block looks much different than is pictured in the photo (s) post 23 and post 33