Pics of pistons

[A70Duster at aol.com]

<< 10/4 to Greg. Go to http://www.mtco.com/~twsharpe/images/Piston2.jpg >>

Question to Tom.

Judging by the pin location in the oil rings, I assume that you have a SBC 
piston with a 6" rod.  I also assume with a custom setup like that, you 
gapped the rings.

What compression was the engine and how was the engine used (daily driver, 
drag strip)??

First, what did you gap the rings at?  From the damage, it looks like the top 
ring gap was too tight, the extra heat expanded/butted the top ring together 
and the weakest part of the piston broke off (valve relief to top ring lan) 
when the top ring was "seizing" in the bore.

If that is the case, then blaming a hypereutectic for breaking like it did is 
like blaming a hand tighten rod bolt that failed.

Looking at pic

http://www.mtco.com/~twsharpe/images/Piston1.jpg

it is more obvious that there are "detonation" imprints on the piston.  Again 
assume a SBC, there is damage in the quench area.  Did you notice (audible) 
detonation/pre ignition?

Did you have open chamber heads?  And did you know what the quench height was?


Sorry for the 20 questions.  I'd would rather learn from people's past 
experience.

Thanks,

Mike


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