Increased Compression?

[Mark Johnson <mjohnlit@xxxxxxxxxx>]

I don9t know where JK took physics, but think about it...

Yeah, if there is carbon (or a dome, or a melted top of a spark plug  did
that once  or whatever on a piston it decreases the chamber volume.
However, the chamber volume is increased on the intake stroke, as well as
the compression stroke.  Assuming the intake pressure is at one atmosphere,
the compression ratio would be the same with or without the reduced volume.

Also, as DASUTO said, it increases detonation.  Sorta becomes a 3glow plug2
on top of the piston.  When the fuel-air mixture starts to burn before the
intake valve is completely closed, you tend to lose the advantage of all
that 3increased compression.2

Unless I9m missing something...

Mark Johnson


>Date: Sun, 17 Feb 2002 09:02:52 -0800
>From: jkerouac@domain.elided
>Subject: re: Carbon on the pistons
>
>re: Carbon on the Pistons
>    I'm not so sure that carbon buildup on the piston tops is such a bad
>thing.
>    Maybe some racers can concur on this: I prefer to leave the carbon
>on the pistons when I had the head off.  Since the chamber volume is
>effectively decreased by the buildup, the compression is therefore
>increased, and since it's due to normal wear and tear, in a stock legal
>way, too.
>'jk

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