Interesting ... my 82 looked like that one and had perfect end float ... not a mark on it. Seems to me it might be a later model block machining process difference.

 

Let me add this....if the scoring is worse on one side and the thrust bearing is worn thin on that side, then, sure, this could be TBF. The first picture appears to show the thrust bearing and it does look thin to me compared to this shot....So, yes, it could be a bad TB, but TBF damage looks a lot worse than the factory machining, at least on S4s. There have been many pictures posted here of this "scoring" discovered when people pulled the oil pan in engines with good crank endplay and intact TBs.

So, compare the thrust bearing thickness and scoring on each side and check the crank endplay.

 

Looking at my 82 block the machining was centred on the crank line, and there were concentric machining circles of ever increasing diameter going outwards from there.

Notice in the first photo that the machining marks are not perfect concentric circles like that, but it looks like they've had several goes at facing those areas. If all blocks had perfect concentric machining to start with, you would expect that crank throw scoring should follow the same radial lines, as they are running from the same centre point.

There can be only two explanations for the multiple sets of maching/scoring circles:
1. Spot face machining was off center to the crank centre line, and the crank throws then scored the block concentric to the centre line (edit: although the 'scores' look a bit too neat for that) ... or
2. Spot face machining was done in two or more passes, and they didn't line each one up to be concentric to the crank centre line.

 

Hmmm... That is different and I did notice the TB looks thin, although it could be the angle. Still most likely factory machining.

 

I've only seen 16V motors without the oil pan.

 

Simples

If the marks aren't perfect circles around the centreline of the main bearings (difficult to tell from the photo) then they are machining marks. (Or the crank is bent more than a banana - you would notice this!)

And another plus point that oil is far too clean for oil in an engine with TBF. It would look like aluminium slurry if the crank had been "machining" the block.

 

And if the cranks touched the block, there would be material transfer to the counterweights too or at least some marks that match the block. As I said before, these are manufacturing machining marks, nothing more.

 

My block with perfect end play specs looks like this. As long as your end play is in spec don't sweat it. Do spend the dough and get a super clamp from Constantine

 

what is perfect end play in inches or MM?

 

New spec for 32V engines is 0.06 to 0.192mm (0.0024 to 0.0076 in). The wear limit is 0.4 mm (0.0157 in).

 

I've been busy with other stuff on the project so just got out from under the car with the end play results.

And the nominations are.....

I measured twice after getting good "clunks" prying to and fro. Used digital micrometer measuring between same flywheel tooth and flat end of crankcase each time.

1st result play = 0.12mm
2nd result play = 0.13mm

I released clamp for measurement but noticed no movement based on paint marks from last check, and the flexplate was flat.