Quench

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Feb 20, 2008 | 11:32 PM

mgbss

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From: Mt Pleasant Michigan

Quench

Once again my eyes hurt from searches

Lots of good reading though (mostly)

Anyway, is anybody running less than .039 quench area ( example: 0 deck with a FelPro 1010) or any other combo, KB pistons suggest .040 for the least some books say as low as .025-.030 Just wondering what some actual engines are running.

Thanks
Joe

Feb 20, 2008 | 11:51 PM

1989TransAm

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On my L98 I'm running the pistons .007" down the hole and the GM .028 head gasket. I'm currently shifting at the 6100 mark and with my new cam upping that to 6300rpm. I would not go less than a .035" quench as there is apparently no advantage to it. Most say .035" to .040" is good.

Feb 20, 2008 | 11:59 PM

Demonic85

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From: sw Ohio

Is the 1010 a thinner gasket than the original GM one?

Feb 21, 2008 | 06:39 AM

mgbss

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From: Mt Pleasant Michigan

Den9omic85
Yes the 1010 is a .039 Gasket the original at least on some years (I have read, I think Alum Heads 87 up) is.051. My 85 had steal shim type (around .015- .020 I think), but that is the HUGE port 76cc head.

89 TransAm,
Are you running a stock bore or a fresh bore with your .035 quench?

Joe

Feb 21, 2008 | 08:53 AM

mseven

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From: The Motor City

Quote:

Originally Posted by mgbss

Anyway, is anybody running less than .039 quench area ( example: 0 deck with a FelPro 1010) or any other combo, KB pistons suggest .040 for the least some books say as low as .025-.030

I would bet that most would recommend around .038.
Aside from theory, the quench distance should be between about
.037 and .044 (the distance between the cylinder head and the piston deck). If you run less than about .035, and at high rpm levels the pistons might hit the cylinder heads. If you run more than about
.044 thousands the quench effect of forcing the fuel/air mix to the center of the cylinder from the cylinders edge area looses both speed and effectiveness.

Feb 21, 2008 | 09:02 AM

anesthes

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From: Salem NH

Dead on. I usually go .005" in the hole and a felpro-1010 on my builds.

Some guys I know run sub .030", with a high silicoln alloy forging with very low expansion properties and H beam rods. I'm running the same, but I still keep it around .044" because even the slightest bit of expansion at high RPM and you might get a tap. really crappy forgings will expand tons.

-- Joe

Feb 21, 2008 | 12:26 PM

1989TransAm

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Mgbss; Yes I'm running a fresh .030" bore.

Feb 21, 2008 | 05:36 PM

mgbss

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From: Mt Pleasant Michigan

I see some info on Forged Pistons do Hypereutectic Pistons make a difference should more area be left or could they be ran tighter, just trying to learn.

Thanks
Joe