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Quench

Old Jan 27, 2007 | 11:52 PM
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What is exactally quench? i know it is affected by head gasket thickness and stuff. because im gonna be cammin my car in the near future and i think this is something i need to know for my part selection.
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Old Jan 27, 2007 | 11:56 PM
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Quench is the "squish area" that is between the piston top at TDC and the deck surface of the head. You can calculate quench area by adding the amount the piston is in/out of the hole to the head gasket amount. Example: .040 gasket and piston that is -.005 out of hole is .035 quench area. The tighter the quench area is, the more turbulent the compressed mixture will be and as a result the air/fuel mixture will be more of a homogenous mix. This will aid is chamber cooling and will be less prone to detonation.

Too small of a quench area on a loose engine is not good because then you risk the piston rocking at TDC and smashing into the head deck.

If you have a stock block a .040 gasket should be fine, will give you a quench area of ~.034
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Old Jan 28, 2007 | 12:47 AM
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Brad if it was -.005" with a .040" gasket. would'nt that make it .045"? I mean if the piston is in the negitive rather than +.005". Is this correct?
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Old Jan 28, 2007 | 12:52 AM
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Originally Posted by JRracing
Brad if it was -.005" with a .040" gasket. would'nt that make it .045"? I mean if the piston is in the negitive rather than +.005". Is this correct?
No, simple math. .040 + -.005 or simply put, .040 - .005 = .035.

Thick about it, the farther out of the hole means that there is less space between the piston top and the head deck.

When pisto n is out of the hole it is negative, when its in the hole below the surface its positive.
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Old Jan 28, 2007 | 02:40 AM
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Street quench margin .035/.045, race can be a tad less
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Old Jan 28, 2007 | 10:28 AM
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My street quench is .028 and has been for a year now . These blocks grow quite a bit
as the come up to temperature and this increase in quench is not accounted for by most people.You can run them this tight if you allow the motor to warm up before revving it hard.Any time you can decrease the quench you are ahead of the game
for wider tuning latitude and increased efficiency as the quench area is dead for combustion ,the less trapped mixture the better volume wise.
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Old Jan 28, 2007 | 12:30 PM
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[QUOTE=brad8266

When pisto n is out of the hole it is negative, when its in the hole below the surface its positive.[/QUOTE]



I thought this was the other way around.
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Old Jan 28, 2007 | 12:32 PM
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Originally Posted by JRracing
I thought this was the other way around.
negative
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Old Jan 28, 2007 | 01:15 PM
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Originally Posted by silverbandit0996
What is exactally quench? i know it is affected by head gasket thickness and stuff. because im gonna be cammin my car in the near future and i think this is something i need to know for my part selection.
I had the same questions. https://ls1tech.com/forums/advanced-engineering-tech/647294-quench.html
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