well now that the stock pistons and rods are just sitting in my garage i wanted to look a little closer at what was broken in my #1 cylinder to cause the low compression. I found that the upper ring was cracked, i also found the the ring land between the #1 and #2 ring was broken for about 1 1/2 inches, basically a chunk about 1 1/2 inch was loose and broken off. and then a 2 inch section of the ring land between the #2 and oil ring was broken too. the thing that is funny is that i never had any detonation and my car never went over 1500*F. So my conclusion is....the stock pistons are pieces of shit. I analysed the fractures and found that it was not due to excessive heat. i also found that the nature of the grains in the break appears to exhibit traits of a fatigue fracture that occured due to small cracks that appeared in the edges of the ring lands. basically, even though my car was tuned rich, the forces of the combustion on the rings appeared to overload the ring lands and cause them to fracture. with repeated load these cracks eventually fatigued the ring land enough to cause a chunk to break loose. again leading me to believe that the stock pistons are pieces of crap. then i tried one more experiment. i grabbed one of the sections of the remaining ring land with a small pliers and tried to break it off, guess what...it broke, with a suprisingly little amount of force. this seals what i think of the stock pistons....i think everyone knows that opinion by now.
hehe
lates
james

Rest In Peace Heidi Doggy

You are correct sir. 99% of all piston failures under boost are the exact same way.

However, i believe it is detonation that causes it, not necessarily just overload - detonation causes violent pressure shifts and stress on the piston, which is why they break the way they do. It's not an instant WHAM goodbye, more of a subtle wear over time from light knock.

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So you think it wasn't detonating.. but I can gaurantee you it was.

Ya dino,
that could be it that goes with what i found when i analysed the fracture. alot of episodes of a little detonation. i was damn surprised of how fragile those pistons were, they had no ductility at all! no elastic range. just solid or broken. i guess that is the nature of cast materials, just good that i got those JE's now i hope they hold up!
lates
james

Rest In Peace Heidi Doggy