Pics of pistons

[Programmer]

>From the second pic, it just looks to me like aluminum from the ring land
that's
marked that piston--not detonation marks...it'll bounce around and can mark
up
every piston in a single plane intake.

Lyndon
----- Original Message -----
From: <A70Duster at aol.com>
To: <diy_efi at diy-efi.org>
Sent: October 14, 2001 8:54 AM
Subject: Pics of pistons


> << 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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