GT block Interchangeable with the S4 block

[tmpusfugit]

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....

[Mpierick]

Pulling the engine this weekend. Thanks.

[tmpusfugit]

Here is a photo of a TBF block web "machined away" by the crank counterweights when the thrust bearing fails...

[MarkRobinson]

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.

[19psi]

Does TBF affect ALL YEARS with automatic?

[tmpusfugit]

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 month


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....

[Danglerb]

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.

[Mpierick]

How do you post pictures?

[Danglerb]

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.

[Mpierick]

Well here we go!!! Could not wait until Sat. to pull the engine. Started Friday night at around 6:00pm.


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.

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.

[tmpusfugit]

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

[Danglerb]

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.

[Mpierick]

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.


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?

[Mpierick]

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

[Mpierick]

Now?

[Mpierick]

Both the Heads and Block look real clean.

[19psi]

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.

[Mpierick]

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

[Danglerb]

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?

[tmpusfugit]

Originally Posted by Danglerb

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