Bae 2nd ring sticking

My bae with 8 easy runs the 2nd ring grove collapsed at wrist pin on 3 pistons, no sign of detonation on bearings or egts, i did get the engine warm setting the timming.

Any idea on the cause??

Thanks
randy

 

Detonation

I've had the same problem, it's detonation. Check your pins, they're probably bent too.