Head gasket question
08-14-2016, 09:12 AM
#1
Head gasket question Hey all,
When discussing my heads/cam swap, multiple guys mentioned "quench" when referring to my head gasket selection, and the number .350" was brought up by one fella. I have no idea what quench is. I'm lost.
Standard bore LS1, 243 heads
I'm wanting to squeeze a little extra compression out of the motor, so I was looking at a 3.91" bore, .040" compressed thickness MLS gasket.
Will this work? If they wont work, what will? Bore and thickness would be
Guys who have 243s on an LS1, what head gasket did you use?
Thanks in advance.
When discussing my heads/cam swap, multiple guys mentioned "quench" when referring to my head gasket selection, and the number .350" was brought up by one fella. I have no idea what quench is. I'm lost.
Standard bore LS1, 243 heads
I'm wanting to squeeze a little extra compression out of the motor, so I was looking at a 3.91" bore, .040" compressed thickness MLS gasket.
Will this work? If they wont work, what will? Bore and thickness would be
Guys who have 243s on an LS1, what head gasket did you use?
Thanks in advance.
08-14-2016, 10:22 AM
#2
FormerVendor
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Pistons Kissing Heads The most perfect instance of Squish would be no distance between the head Quench Pad and the Piston Crown.
This allows for a cooler piston crown, turbulence in the cylinder that WILL MIX fuel with air, thus Knock Resistance.
The correct value can allow for an increase in Static Compression Ratio of .5 compared to a large amount of Squish (.035"+) AND have the same Knock Rating.
My "target value" distance is .025" at Zero RPM.
Then as RPM is increased, temperatures increase, pistons "slap", this distance will decrease.
Most here will take the "safe" stance of .035" as good advice which I ALSO support.
The GMPP gasket is fine as is the Fel-Pro MLS gasket, both engineered under License from my friend in Japan that invented the art of MLS.
Lance
This allows for a cooler piston crown, turbulence in the cylinder that WILL MIX fuel with air, thus Knock Resistance.
The correct value can allow for an increase in Static Compression Ratio of .5 compared to a large amount of Squish (.035"+) AND have the same Knock Rating.
My "target value" distance is .025" at Zero RPM.
Then as RPM is increased, temperatures increase, pistons "slap", this distance will decrease.
Most here will take the "safe" stance of .035" as good advice which I ALSO support.
The GMPP gasket is fine as is the Fel-Pro MLS gasket, both engineered under License from my friend in Japan that invented the art of MLS.
Lance
08-15-2016, 03:24 AM
#3
Never use the head gasket to adjust compression. It's such a small amount that it really isn't worth talking about. Use the head gasket to adjust quench, and you'll gain more power and efficiency. If you want more compression, change the pistons or shave the heads.
Do a google search on "piston quench" and you'll find gobs of information about it.
Generally speaking, the pistons on an LS1 stick up out of the block about .006-.007". With an .040" head gasket, you'll have about .033-.034" of quench area. That's a little tight unless you plan on keeping the rpm's low.
A lot of engine builders still say that .040" is minimum quench distance. But others say that an aluminum block will grow, so .035" is the minimum.
IMO, you should measure the piston height in all 8 cylinders, then pick the head gasket that will give you the quench you want on the tallest piston.
Do a google search on "piston quench" and you'll find gobs of information about it.
Generally speaking, the pistons on an LS1 stick up out of the block about .006-.007". With an .040" head gasket, you'll have about .033-.034" of quench area. That's a little tight unless you plan on keeping the rpm's low.
A lot of engine builders still say that .040" is minimum quench distance. But others say that an aluminum block will grow, so .035" is the minimum.
IMO, you should measure the piston height in all 8 cylinders, then pick the head gasket that will give you the quench you want on the tallest piston.