aeronca65t
Great Pumpkin
Offline
This piston (#1) came out of my 1500 Spridget in early '04 (while I was rebuilding it). I was surpised to see this much damage since the car was running OK and was not "missing" on this cylinder. Prior to this dissassembly, it had just finished decently in a 1 hour race at Summit Point (WV).
A portion of the upper land failed (I guess) allowing the upper piston ring to break into a bunch of pieces. I found some pieces of the ring in the sump. The square-ish marks on top of the piston were caused by pieces of ring hammering into the top. The head in #1 area looked like it was bead-blasted, but no other damage.
This was a 7.6:1 low-compression piston. The engine has been rebored (+.020) and I've put in 9:1 flat-top pistons instead. New cam, ARP hardware, 3-angle valve job and a bunch of other stuff too. Other than a minor bit of vapor lock, it runs good now!
A portion of the upper land failed (I guess) allowing the upper piston ring to break into a bunch of pieces. I found some pieces of the ring in the sump. The square-ish marks on top of the piston were caused by pieces of ring hammering into the top. The head in #1 area looked like it was bead-blasted, but no other damage.
This was a 7.6:1 low-compression piston. The engine has been rebored (+.020) and I've put in 9:1 flat-top pistons instead. New cam, ARP hardware, 3-angle valve job and a bunch of other stuff too. Other than a minor bit of vapor lock, it runs good now!