Piston Carnage

[FlightRisk]

This is out of my rear cyl. 701 bored .75 and ported, 33 cc domes around 185 psi. The missing corner is near an intake port.

Anybody give me an indicator on why? I run around 93 octane or so... front piston looks perfect, good wash and color on the plug. Is this heat related or crack? the edge isn't sharp, it looks bead blasted.

Thanks for the feedback.

 

[luker]

Imo to much comp or timing ,

 

[tor*p*do]

single or twin carb?
35 cc domes may have prevented this

 

[FlightRisk]

twin carb, ada head, EPIC ignition.

 

[ryan]

deto

 

[ATS_Aaron]

Detonation doesn't melt the piston like that. That piston has suffered a lean condition.

Aaron

 

[FlightRisk]

I will confirm the lean issue, I have a feeling it may have been due to my intake gasket. I agree it might be a lean issue. The front piston looks perfect, good wash and good color.