i had super low compersion in my motor going from 4 -1 120, 120, 100, 220. so i figured rings i took the motor apart found the valves are all good, and the cylinder walls all look perfect. so i pulled the pistons out while pulling them i notice the pieces of piston falling in my hand.....YAY

here is one of the 3 cracked pistons all of them looking simaliar


here is the top of the same piston as follwed they all look the same



Modified by Mr. HYDE at 3:21 AM 10/18/2005

 

More likely than not it was caused by detonation. You might want to put a knock sensor on your motor or lower your compression ratio or at least not advance your timing so far.