Looking for tips on S52 engine post-failure analysis

[LJ851]

^ Why only 1 piston affected, though?

A worn thrust bearing would also generate massive side loads to the piston but all 6 would be affected.

My current thoughts:

I think piston failure was end of this engine. Possibly a wrist pin circlip got hammered out by side loads/rod at an angle, it doesn't take much. Wrist pin shifted out until it cleared one wrist pin boss and put the other boss in single shear which didn't last long.

[wazzu70]

Lorin, if the issue is TV related I figure #1 is the most likely to be impacted. If it was any other cylinder I wouldn't consider this option.

My guess/assumptions could very well be wrong though. Your idea is a very good one and probably more likely.

I think the material in the cylinder is from the piston....just not sure what caused it to deposit :) I don't think the failure sounds valvetrain related.

[LJ851]

Lorin, if the issue is TV related I figure #1 is the most likely to be impacted. If it was any other cylinder I wouldn't consider this option.

Nick, why number 1? Is that typical for TV damage on S52?

[wazzu70]

The nose of the crank seems to bear the grunt of damage from TV. Its also the reason the oil pumps on these motors have lots of issues, and its now common to see the crank trigger on the flywheel side of the engine.

Since the S52 is a TV nightmare, I just figured it seemed possible they are related. It could just be dumb luck though that #1 was the cylinder that had issues.

Check out this white paper on TV: http://www.bhjdynamics.com/index.php...0l8tdu08dvblj2

The crankshaft bending vibration toward the end talks about the nose of the crank and its issues. Also the first mode shape shows how the crank nose does the most dancing.