The marks are only on one piston, and do not appear very deep. Any thoughts are welcome.

Should I smooth these marks out with a dremmel before putting the heads back on?

It may have slow upload speed.

http://12.221.222.200:6580/piston.jpg

 

I would say that that piston is f!*#$. If it was my motor I would replace that piston, have the crank bearings checked/replaced and crank checked for trueness.

 

from what is the ??? If you found the culpit and it isn't something that can redamage.. I would run it.. But thats me and I run anything.. lol

 

It looks like the tip of spark plug fell off and bounced around in the CC before getting forced out of the exhaust valve.

Something metal got into the CC and bounced off the piston repeatedly.

I'd also check your head on that CC and check your cylinder walls for scoring or galling.

 

holy c##p that piston is F up man it is normal for our pistons to have one tiny indentation they all have it it's this tiny perfectly round hole on the top of to the side but that many holes aint normal man put another piston and see what caused the damage other wise you gona be replacing that new piston in the near future

 

Damn Greg, that really sucks.

I don't think I'd be comfortable with reusing that one either.

 

Actually, there's no way I'd re-use that piston.

 

Damn dude, did you hear anything out of the ordinary?? Detonation maybe? How did the plug look in that cylinder? Get a new one, or go with some forged ones while you are at it. Ugh

 

Did not hear anything strange. It doesn't look like detonation to me. The plugs all look great. I am just going to put it together and wait to get a 422 down the road.

 

Weird You think you would have heard something with that damage.

 

Something got into the CC chamber, had to have to make those defects in the piston's surface.