Is this possible? (burned piston and rings)

[OilPatch197]

I was tearing down a 2.8 for a rebuild and noticed that cyl #1 had a squarish sink, about 10mm x 5mm and it is basically centered on the grove of the 2nd compression ring down past the oil control rings, at about the depth of the ring grove.

The other pistons are not like this one! I don't have pictures yet, I will take pictures if anyone is interested.

What I don't get is how did the piston ring melt? I would have figured if it got that hot that I would have a hole in the piston, I am quite surprised that the piston did not seize up when it overheated.

 

[97BlackBetty]

Engines just simply do goofy stuff somtimes, it could have been an imperfection in the metal used. We had something similar happen like that on a diesel, manufacturer never gave us a response as to why.

Oh and

 

[krugford]

+1. Sometimes strange stuff happens. I want pics...

Oh, 97BlackBetty, you probably didn't hear back because the tech tearing that engine apart from the factory and the engineer examining those parts are so far removed from the dealer it's not even funny. As someone who is in charge of inspecting broken engines to determine root cause of failure, the last thing on my mind is letting the dealer know why it failed. Unless of course it's determined to be dealer error, which happens to the best of us, then they hear about it!

 

[97BlackBetty]

Krugford, it was aboard a commercial vessel, most of the time we have failures, especially those related to failures of vital parts, techs from the companies come out. We had a Sulzer diesel sieze a main bearing, the techs came out and collected every piece of metal out of that engine to do failure analysis on it. They also came out with some really cool tools! When we burnt through that compression ring, we were requested to send it to the manufacturer.
Justin

 

[krugford]

ah, that big of an engine is a little different story.

 

[skippy]

Krugford, it was aboard a commercial vessel, most of the time we have failures, especially those related to failures of vital parts, techs from the companies come out. We had a Sulzer diesel sieze a main bearing, the techs came out and collected every piece of metal out of that engine to do failure analysis on it. They also came out with some really cool tools! When we burnt through that compression ring, we were requested to send it to the manufacturer.
Justin

do you guys do lube oil analysis through a lab on those engines?we went nuts in the navy sending off samples and reviewing spectographic analysis reports.

 

[LearjetMinako]

Sorry, had to. These old 2.8 & 2.9 can do some weird things.

 

[97BlackBetty]

yea we do lube oil analysis, it depends on what the manufacturer wants, we have simple tests that we do on board routinely to check viscosity, we also send them out to the manufacturer to have it checked. A few of the guys that im in school with were navy and coasties, they hated it too. Mostly we send out samples and they tell us whats wrong and needs attention. we get the full report but they break them down to A+B= whats wrong with it. I have heard a lot of good stories about how involved andyet clustered the navies testing is, one of my instructors was a nuke chief and the other was a chief on a sub.

 

[OilPatch197]

okay here are the pictures:

 

[skippy]

never seen anything like that.did it gouge the cylinder?just amazing.

 

[OilPatch197]

The cylinder is in perfect condition, just needs a hone!

 

[ZMan]

well thats strange.

I've got a 2.9l piston I saved from "the bitch"..its all spider cracked and the rings are broken.