Waynegs3

OK, so last night I pulled the pan on the 90. And…..drum roll please….. thrust bearing failure. So here is my question, I understand that almost all blocks are destroyed from TBF. You can see obviously from the pictures, that the crank has worn into front and back of bearing caps and block. I also heard that reason it’s considered catastrophic failure (and my understanding may be flawed) is because the block cracks when the crank hits it, and therefore it becomes financially unfeasible to R&R when other newer motors run in the $2k arena.
So, how do I determine that my block is toast? Can I see the crack? Is there a common place for it? Am I one of the unlucky lucky ones that can salvage his motor? Just curious…
I’d love to save the $2k and fix what I have if you know what I mean.
Any suggestions and comments are greatly appreciated.

Regards,
Wayne Schlosser

BPG_Austin

Wayne, have you measured your crank endplay yet? Do that first and post your results. I had TBF a few years ago and did mains/rods. block was fine as it was caught in time. Car runs great today but DANG it that a big job.

That looks like factory honing to me and I still see the ends of your thrustbearing intact. I think it might be a bit premature to declare TBF. Measuring your endplay will give you the answer you need to determine TBF.

blown 87

First off, you are dreaming if you think you can repair that for two grand, even if the block is ok.

What you need to find out is did the thrust bearing spin?
You are going to have to pull the motor and split the crank girdle to find that out.
I am not seeing where the crank hit the block.

The last one we did on a motor that had a worn thrust bearing ended up with about four grand in parts, and we did not take the heads or intake off.

Good luck.

BPG_Austin

attached picture of my '87 w/o oilpan. Honing is normal on webbing.

Tony

Dont panic yet..What your looking at is normal. I havent seen a block yet that doesnt have that.

Its the measurement your worried about...or when the motor siezes when hot.

I'll buy that "toast" motor from ya for 500 bucks

Waynegs3

Bill, you and Kirt did the measurements, do you remember the results?

Waynegs3

Oh and blown 87... i meant $2k for an engine from ebay...

GregBBRD

I don't see much wrong, here. The blocks all look like that and the heat mark on the crankshaft is normal.

You might have a bearing issue, but you will need to take a better picture of the thrust bearing, for us to see it.

Bill Ball

I agree these pictures does not show any damage but just normal factory block/girdle machining. Weird. The endplay was 1.65mm which is huge. There should be very little thrust bearing left. I see a big space there which could be the bearing or empty space. If empty, I would then expect to see a lot of damage from the crank throw hitting the block/girdle. Looks like a lot of bearing is still there. Hard for me to explain a this point. Take pics from both sides of the thrust bearing. Maybe the damage is on the other side.

Where is the car? If still local, I'd like to see it.

Bill Ball

Here some pics of a damaged block from Rich Andrade's review of TBF.

Rich9928p

Bill - thank you for crediting the photos - sharing this information is why I wrote the article!

Rich

namasgt

With the front belts removed and the spark plugs out, turn the engine with hand and see how it feels. Like others have said already your trust bearing looks fine.

Waynegs3

OK here are a few more pics...
Also, there is a ton of graphite material in the oil pan, enough to scoup out with a spoon, probably id say an 6 oz of this metal muck, its metal shavings, cause the magnet like its.
Oh and Tony, it was seizing when it got hot...
Bill, if you recall you did mention you were worried about oil pressure when you were driving it.
When I use a big ccrew driver, I can walk the crank forward till the crank 'touches' the bearing cap. Which creates a large space on the other side, approx 3/16" gap.
Also, looking at the material of the bearing, it has a bronze looks to it, actually almost gold .
So... its possible, not TBF, but Main bearing failure.. possibly?
Wayne

Imo000

I can still see the bearing....all look normal too me. That machining mark on the block is normal.

Bill Ball

You should help us out here with some indication of front/rear and where the thrustbearing is or was in the photos. Regardless, picture 7 looks like damage. Still hard to tell. The rest look OK, although there are some gaps that I can't evaluate.