what happened to the LS1 I bought - #7 piston busted
Hey guys, trying to figure out what happened to this engine; getting a little confused.
Bought an LS1 from a wrecked 2000 corvette with 40k miles, and I was told the engine was running just fine right before it was pulled.
Got it home, pulled the heads, and saw this:
Broken at the ring land, common on #7, etc (nitrous maybe???). Now all the other pistons are fine. What's confusing me though is...the cylinder wall looks fine, and the combustion chamber looks good, valves look good.
I mean with a broken piston like this, shouldn't there be some damage on the cylinder wall, or the combustion chamber/valves?? What could have happened?
Mine did the exact same thing at 103,000ish miles, only on number 5. I also had a cracked block directly opposite the ring land failure (@5 o'clock position). I don't use nitrous either. Let me see if I can find the thread and pics.....
Yeah, it's really weird (re: suspicious) that a huge chunk of aluminum piston like that evacuated the engine and didn't leave any damage behind. 9 times out of 10, a piece gets caught in the quench area between the head and piston, and sticks into either of the surfaces. You usually find chunks in the manifold as well.
See if you can find any signs that the engine might have been rebuilt. I think that might be the more likely explanation.
Not sure about where the missing piece of piston went, but it looks like the detonation could be caused by an oil contamination issue. Excess oil in your combustion chamber can cause detonation even in a low compression engine.
__________________ TT632's Vehicles:
4th gen SOM Formula, 700 HP 427 or 1350 HP TT 421
05 Avalanche. 97 S10. 95 Firebird. 87 Olds 442 60k all orig. 05 POS Rav4. 87 Samurai. C4 Corvette
The chances of a big chunk of metal finding its' way out of the cylinder through the exhaust valve without doing further damage along the way are VERY slim. Conversely, who would put a motor together with a piston that looks like that? Time to call Perry Mason on this one.
Mine made it out of the exhaust port. There were no pieces in the oil pan, and like stated in my thread, there was not any room around the ring for pieces to get by. It is very possible for a piece to shoot out of the exhaust valve.
I ended up with an iron 6.0L block bored to 4.07" with Wiseco pistons, Eagle rods, and a Compstar 4.100" crank.
1999 Formula LQ9 421, T56, 9"
2008 Suzuki Bandit 1250
2010 Silverado ECSB Z71, 5.3, 6L80