optimal quench height?
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12 Second Club
Joined: Feb 2006
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From: Catlettsburg, Ky
optimal quench height? what is the general rule as far as optimal quench height for an LT1?
I've heard .040" and then I've heard .030'? which is it?
all motor 355, steel rods, and forged pistons if all that matters?
thanks guys.
I've heard .040" and then I've heard .030'? which is it?
all motor 355, steel rods, and forged pistons if all that matters?
thanks guys.
Typically you want to be around .035-.040 on your quench, but you have to make sure the rest of you combo works first. Just like everything else it's just a guideline. Stock quench is like .075.
I'm running .041... The Ol' George Carlin look alike wouldn't zero deck mine like I wanted and left them .026 in the hole. I had to modify a gen1 gasket that is .015" to get mine down to .041
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Verdad Gallardo Thread Starter
12 Second Club
Joined: Feb 2006
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From: Catlettsburg, Ky
my setup on the car is pretty much dead at 6500rpm, so there is VERY little need for it to ever be twisted any higher.
I was thinking zero deck with impala gaskets (.029" compressed, correct?) which would give effectively a .029" quench height (duh!)
I can imagine a rod, piston, crank throw, and warm oil clearance being anywhere near .029" but I might be wrong.
is .029" too tight? I wouldn't think so if everything was INDEED "blueprinted" to assure symmetrical crank throw length as well as having a square deck surface, and quality rods and pistons are used (respectively)
what are fel-pro gaskets for aluminum head motors compressed? .043"?
.043" quench height is a hell of a lot better than the stock .060+!
I was thinking zero deck with impala gaskets (.029" compressed, correct?) which would give effectively a .029" quench height (duh!)
I can imagine a rod, piston, crank throw, and warm oil clearance being anywhere near .029" but I might be wrong.
is .029" too tight? I wouldn't think so if everything was INDEED "blueprinted" to assure symmetrical crank throw length as well as having a square deck surface, and quality rods and pistons are used (respectively)
what are fel-pro gaskets for aluminum head motors compressed? .043"?
.043" quench height is a hell of a lot better than the stock .060+!
I installed mine without rings and took measurements top(valley side) and bottom of the pistons....I measured mine by rocking them up and down and averaged the two numbers.
If thats what your asking....
I used the felpro-1094 gasket....
You have to enlarge the water passages on the top of the gasket. Its the two passages on the top left and right side of the block. I also trimmed where the oil drains back into the valley through the head. I used a dremel with a cut off wheel to enlarge the holes and then sprayed them down with copper spray-a-gasket ....You have to be very careful to not cut into the fire ring and not get to close to the top of the gasket. I also used a very,very small amount of permatex around the water passages.
Mine has held together for 14 miles...
There is a couple of guys on cz28.com that have ran these gaskets with no problems. Plus there only $19 to $20 apiece.
If thats what your asking....
You have to enlarge the water passages on the top of the gasket. Its the two passages on the top left and right side of the block. I also trimmed where the oil drains back into the valley through the head. I used a dremel with a cut off wheel to enlarge the holes and then sprayed them down with copper spray-a-gasket ....You have to be very careful to not cut into the fire ring and not get to close to the top of the gasket. I also used a very,very small amount of permatex around the water passages.
Mine has held together for 14 miles...
There is a couple of guys on cz28.com that have ran these gaskets with no problems. Plus there only $19 to $20 apiece. Last edited by TravisA; Nov 15, 2007 at 07:53 AM.
Staging Lane
Joined: Jan 2007
Posts: 71
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From: st-jean baptiste, quebec ,canada
is there something i dont get here ?
if you run zero deck height and .029 gasket youll get .029 quench but with a 54cc head your CR will reach something around 11.8:1 aint that way too high?
or like I asked ,is there something i dont understand?
in my case I have .20 deck hieght ,ill put a .026 mr.gasket to obtain around 10.8:1 Cr it looks more then enough to me ...
Dan
if you run zero deck height and .029 gasket youll get .029 quench but with a 54cc head your CR will reach something around 11.8:1 aint that way too high?
or like I asked ,is there something i dont understand?
in my case I have .20 deck hieght ,ill put a .026 mr.gasket to obtain around 10.8:1 Cr it looks more then enough to me ...
Dan
static compression ratio is not a big deal, dynamic compression ratio is what matters.
Bigger cams give you a smaller dynamic compression ratio......so running 12:1 with a larger cam is just fine, as long as quench is good
Bigger cams give you a smaller dynamic compression ratio......so running 12:1 with a larger cam is just fine, as long as quench is good
TECH Junkie
Joined: Dec 2005
Posts: 3,092
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Mighty Whitey. If you want to use the .029 Impala head gasket why don't you leave the pistons say .006" down the hole instead of a zero deck. That would give you a .035" quench. There is no magic in a zero deck.
Staging Lane
Joined: Jan 2007
Posts: 71
Likes: 2
From: st-jean baptiste, quebec ,canada
I know all that crap about static compression .....
but still 54cc+ zero deck height +.026 gasket makes for too much compression unless you go for at least 245 dur @.050 i dont think that most run these ...ill run aprox 235 dur @ .050 and no way id go less then .040-.045 quench on a DD .....
Dan
but still 54cc+ zero deck height +.026 gasket makes for too much compression unless you go for at least 245 dur @.050 i dont think that most run these ...ill run aprox 235 dur @ .050 and no way id go less then .040-.045 quench on a DD .....
Dan
I am running about .052 quench on a genuinely never disassembled stock shortblock .026 measure near center of piston with a straight endge and feeler gauge, and a .026 gasket. 53.1cc chamber, I come up with about 11.2-3 static compression and she pumps just shy of 230psi on a gauge. 8K miles a year on 93 octane.
