1994-2002 [Subscribe to Daily Digest] |
FWIW, I used to do piston failure analysis for AE GOETZE/Federal Mogul. I have sort have been following this discussion. It seems like you are going to have a pretty difficult time proving anything to an OEM based on metallography of a piston. if you could show one of the following you might have a case:
1. Piston composition does not meet spec (You could probably get a sample run by Arc-spark at an independant lab for $75)
2. Piston microstructure does not meet spec.
3. Piston forming defects are observed (they machined your part wrong). This will be difficult to see since your piston is already toast (I am guessing these are die cast, so they are near net shape when they are lightly machined on pin bores, skirts, ring lands and for valve clearance)
In this case, the amount of grain growth you are going to see during service due to heat will be pretty minimal (especially since the temperatures needed for accelerated grain growth are the ones that would destroy the mechanical properties of your piston). These pistons will be eutectic or hyper-eutectic composition , so the Silicon-rich eutectic phase is going to constrain most Al grain growth at service temps. Most microstructural damage you will see will be catastrophic at the site of failure (perhaps molten Al) and on the piston crown, where you may be able to see the result of detonation (small to not so small areas where the piston material has literally been blown right off of the service or has melted) or oxidation/soot concentration in your crack as it propagated through the piston.
I think it would be a blast to section and do FA on your piston, but I think any satisfaction you will get will be limited to personal satisfaction, not monetary.
Good Luck
posted by 136.237.60...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
![]() |
![]() |
![]() |
![]() |
![]() |