Piston won't burn out, it breaks. The pistons are cast and extremely brittle under the right conditions. One of those conditions would be if impact was done on outer edge of piston up to 1/4" in, cracks there often let big pieces of the top piston ring land come loose later at any time depending on how cracked. You could be driving a time bomb but no way of knowing when it could happen. Could last forever, could break tomorrow, I've seen many cast pistons do it.
Depending on where piston was in stroke it could have yielded skirt to crack or maybe even break off a tang too, but you can't see that from the top. You could easily have a broken ring in there too.
You're the one that looked at it, your skillset now determines the outcome. I've done that too and on some the damage was only cosmetic and harmless, others no way. When person insisted on running it, it broke in a week.
You're in the hands of the SPI god now.
Last edited by amc49; 12-12-2012 at 11:27 PM.