thats what i mean,i know detonation is violent, so if it was detonation ud think there would be damage on the top where the detonation occurs not on the lands, and i would think it would occur in more places other than this one small spot plus, thought it would do damage to the rings. this is the only damaged piston and the rings on all pistons werent touched, im no expert but i think detonation would occur on all the pistons not just one.... ohh wlel at the end of the day doesnt matter the engine is blown next time i wont be doing the same again. it will be tuned by a professional with proper equipment.