What do you think is the cause of this piston damage?.

Diamond 2618 forged pistons. NA application. Tuned with 12.8 AFR.

Note; Only pistons # 5 and 7 got damaged. Others were fine. Spark plugs tips were broken and melted.








Spark plugs. All three are on driver side.

 

Show us the heads

 

EXTREME detonation! That thing would have had to been rattling HARD to break forged piston like that. Basically too much timing and not enough fuel.

 

I just noticed something... Both pistons broke where the top rings come together. This really makes me think that the ring gaps may have been set too tight and then they expanded and butted together, got tight and contributed to breaking the ring lands.

 

or a combination of both.........

 

Is it me or is there a butt load to much piston to cylinder wall clearance there?

I agree... severe detonation. You can see where it etched the ring land that is still there. Piston let go then took out the spark plugs.

 

X3 severe detonation! maybe she went lean and had to much timing.

 

WOW

 

Who was your tuner :O !

Damn, so that's how detonation failure looks like, poor 55's.

 

Correction: Diamond 2618 forged pistons.