I recently got a chance to take a better look at my torn down parts, and the diagonal wear at the bottom of the piston skirts doesn't seem to look normal. The two pics are both sides of one of the pistons. The direction of wear on each side is opposite to the other side. Looking at this and the thrust washer, my guess is there was some slop in the crank end play? Unfortunately, I don't have my crank anymore to check it with a dial indicator. Any thoughts?





Only the thrust washer facing the clutch looks like this. The other one is barely worn.


Corresponding area in the block where that thrust washer sits. The previous owner must have really pushed the oil change intervals.

 

Oh wow that is dirty! That is probably the cause of the wear then, being that the oil wasnt changed when it should have been. How do the main bearings look?

 

Bearings are flawless. Crank journals were measured to be perfect as well. I should say that the flash exaggerates the oil stains.

 

Aside from the varnish I don't see anything terribly worng with that block but precision instruments tell a more detailed story.

 

Are the thrust washers in spec?

 

In spec as in thickness? I have no idea since there's no spec listed for it. Suppose I'll find out when I have new ones to compare with.

 

Crap, I couldn't remember. I don't have my Helms handy (not at home). I thought there was a spec listed for the thrust washers. Or is there only a spec listed for crank end play?

Regardless, I don't think crank end play was a problem. The wear doesn't really look all that abnormal. The piston rocks at TDC as the engine runs, so that might be the wear you're seeing.

 

Only a crank-end play spec is listed.

Another question: cyl one rod is visually slightly bent. The only way it could've happend under my ownership was fuel hydrolock, but the injectors would need to be run continuously for a very long time to hydrolock a cylinder right? Is it possible for a motor to run with a slightly bent rod..ie. previous owner took some water in at some point?

 

I guess it's plausible that the motor took in water but wouldn't it probably have effected the rest of the cylinders? i don't have any experience with hydro-locking but I would guess that you'd have to be pretty lucky to only get enough water ingested to bend one rod from one cylinder and do no more damage. and on top of that have your car still run. I'd assume if it happened to one cylinder, it'd happen to all of them.
Thats me assuming though.
possible to run with a bent rod, yes, if it's not so severely bent the rod ends up coming in contact with the block

 

Yes, with a bent rod you can expect to get a much lower compression in one cylinder than another and you can still have a running engine with one or more bent rods.

 

What would the bearings of bent rod, that's been run for a while, look like? My compression's always been on the low side since I bought the car, don't remember if this one was signifcantly worse.

 

oh damn that is bent pretty bad! At least it bent in the right direction. I'm sure that bearing took a beating when it happened.

 

If it had been run like this for a long time, the bearings would be trashed right? The skirt on this one's piston has a little more horizontal wear, but nothing that'd really stick out at you.

I'm thinkin this was the result of fuel hydrolock, even though I'm not sure how it would've happend. Can't think of any other explanation.

 

It's hard to see in the picture, but I think the diagonal wear on the pistons would have to be from installation, removal, or someone sanding them the last time they were out; I don't see how you could get anything other than linear wear marks from the piston reciprocating in its bore. On the thrust washers, the crank end play is basically the same thing as the thrust washer clearance. The two bearings are the same so if you have to reuse them you can swap their positions. You could also disconnect the clutch cutout so you can start the car without holding the clutch in, but this is more of a problem with really stiff pressure plate springs. On the bent rod, the only reasonable way I can think of that happening is hydrolock. It doesn't always happen to all cylinders, and it would only take ~50cc of liquid. It might not be a recent event either. If the rod is bent so that pin and crank bores are still in line, then you basically have a shorter (and weaker) rod and would not necessarily see abnormal bearing/pin wear. Be glad the rod didn't break and trash the block.

 

None of these parts (hopefully the other three rods are ok) will be reused in the rebuild. The bent rod is just really nagging.

The wear at the bottom of the skirts looks similar to what's above, only a little more pronounced. Considering the diagonal wear at the bottom of the piston skirts (on each of side of the piston) are in opposite directions and on all pistons, wouldn't it have have to be as a result of longitudinal movement? Either crank end play or excessive rod movement on the journals?