Head gasket thickness and cam selection
03-12-2003, 08:27 AM
#1
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Join Date: May 2000
Location: Mobile, AL 36611
Posts: 120
Head gasket thickness and cam selection
I just got my heads yesterday and here are the specs:
2.00/1.56 Manley race flow valves
Crower Springs, Chromemoly locks and retainers Good to .580 lift
Comp Cams screw in studs and guide plates
Flow as follows:
No Port attachments
.100 71/62
.200 133/112
.300 187/157
.400 219/185
.500 248/192
.550 258.5/193.5
I was talking with the guy I got them from and he suggested to run the Impala head gasket b/c its thickness is .0029 compared to the f-bod .0039 and would, of course, raise compression. Would there be any downside to going with the Impala head gaskets? Also, I'm using the LT4 Hotcam and he recommended the CC XE 230/236 cam. This is a daily driver and gas mileage isn't THAT big of an issue to me, but what would you guys do? Go with the Hotcam or the CC cam? My goal is to pretty much keep up with or edge out a Z06. I'll also be using GM 1.6 rr's. Thanks for any advice!
'95 T/A M6, 52mmtb, LT4 km, TunerCat, !CATS, TPIS Headers, Flowmaster, Moroso CAI, Eibach Pro kit
2.00/1.56 Manley race flow valves
Crower Springs, Chromemoly locks and retainers Good to .580 lift
Comp Cams screw in studs and guide plates
Flow as follows:
No Port attachments
.100 71/62
.200 133/112
.300 187/157
.400 219/185
.500 248/192
.550 258.5/193.5
I was talking with the guy I got them from and he suggested to run the Impala head gasket b/c its thickness is .0029 compared to the f-bod .0039 and would, of course, raise compression. Would there be any downside to going with the Impala head gaskets? Also, I'm using the LT4 Hotcam and he recommended the CC XE 230/236 cam. This is a daily driver and gas mileage isn't THAT big of an issue to me, but what would you guys do? Go with the Hotcam or the CC cam? My goal is to pretty much keep up with or edge out a Z06. I'll also be using GM 1.6 rr's. Thanks for any advice!
'95 T/A M6, 52mmtb, LT4 km, TunerCat, !CATS, TPIS Headers, Flowmaster, Moroso CAI, Eibach Pro kit
03-12-2003, 09:15 AM
#2
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Join Date: Aug 2001
Location: Nashville
Posts: 2,262
Hey Bud,
First the stock LT1 gasket is .049
But anywho i like raising the c/r somewhat on a n/a setup and i would switch to a impy or 1074 gasket.
I ran the 230/236 xe cam and loved it. If your looking for more power than this cam is going to make more than a hotcam.
But none the less i will get this over to LT1 Tech as these are more reg tech questions. Thanks.
First the stock LT1 gasket is .049
But anywho i like raising the c/r somewhat on a n/a setup and i would switch to a impy or 1074 gasket.I ran the 230/236 xe cam and loved it. If your looking for more power than this cam is going to make more than a hotcam.
But none the less i will get this over to LT1 Tech as these are more reg tech questions. Thanks.
03-12-2003, 09:32 AM
#3
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Join Date: Aug 2001
Location: looking for a flow bench so Brook and I can race
Posts: 3,505
Originally posted by kmook
Hey Bud,
First the stock LT1 gasket is .049 But anywho i like raising the c/r somewhat on a n/a setup and i would switch to a impy or 1074 gasket.
I ran the 230/236 xe cam and loved it. If your looking for more power than this cam is going to make more than a hotcam.
But none the less i will get this over to LT1 Tech as these are more reg tech questions. Thanks.
Hey Bud,
First the stock LT1 gasket is .049
But anywho i like raising the c/r somewhat on a n/a setup and i would switch to a impy or 1074 gasket.I ran the 230/236 xe cam and loved it. If your looking for more power than this cam is going to make more than a hotcam.
But none the less i will get this over to LT1 Tech as these are more reg tech questions. Thanks.
I'm going to have my heads milled and use he 1074 gasket and hopefully bump my compression up to around 12:1. If i could, I would go up to 12.5 or 13.1
Then again, shes not my daily and will see 2-3 weeks of street time a year so for those few miles i can afford to mix some race fuel
03-12-2003, 09:57 AM
#4
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Join Date: Mar 2002
Location: Bloomfield Hills MI
Posts: 1,842
Also, running a smaller headgasket makes the quench distance better. I am currently running an LT4 head gasket which bumps the c/r a little but it also maximized your air fuel ratio by closing the area between the piston and the flat part of your heads.
Last edited by Rodrigues; 03-12-2003 at 10:32 AM.
03-12-2003, 12:35 PM
#5
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Join Date: Aug 2001
Location: looking for a flow bench so Brook and I can race
Posts: 3,505
Originally posted by Rodrigues
Also, running a smaller headgasket makes the quench distance better. I am currently running an LT4 head gasket which bumps the c/r a little but it also maximized your air fuel ratio by closing the area between the piston and the flat part of your heads.
Also, running a smaller headgasket makes the quench distance better. I am currently running an LT4 head gasket which bumps the c/r a little but it also maximized your air fuel ratio by closing the area between the piston and the flat part of your heads.
thats one weird way of putting it..
it will allow your air and fuel to mix better allowing for a better and more complete combustion cycle.
and a smaller quench distance isn't always better, but the Lt4 headgasket can make it smaller than OEM.
Asking someone more knowlagable than myself a few minutes ago- he explained it to me this way:
as a rule of thumb less quench = more squish = better vortex = better swirl = better a/f MIXING (not ratio at all. your a/f is whatever it is). And Impala head gaskets will provide more compressoin. however this is not always the case and had to predict.
Last edited by treyZ28; 03-12-2003 at 12:57 PM.
03-12-2003, 04:42 PM
#6
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Join Date: Nov 2001
Location: In a house by the bay
Posts: 2,985
Originally posted by treyZ28
Asking someone more knowlagable than myself a few minutes ago- he explained it to me this way:
as a rule of thumb less quench = more squish = better vortex = better swirl = better a/f MIXING (not ratio at all. your a/f is whatever it is). And Impala head gaskets will provide more compressoin. however this is not always the case and had to predict.
Asking someone more knowlagable than myself a few minutes ago- he explained it to me this way:
as a rule of thumb less quench = more squish = better vortex = better swirl = better a/f MIXING (not ratio at all. your a/f is whatever it is). And Impala head gaskets will provide more compressoin. however this is not always the case and had to predict.
-Mindgame
03-12-2003, 04:58 PM
#7
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Join Date: Aug 2001
Location: looking for a flow bench so Brook and I can race
Posts: 3,505
Originally posted by Mindgame
The quench distance has nothing to do with "swirl". Swirl and tumble are independent.... not combustion related as they are totally dependent on the port itself. I think theres some confusion in the terminology... but what's new.
-Mindgame
The quench distance has nothing to do with "swirl". Swirl and tumble are independent.... not combustion related as they are totally dependent on the port itself. I think theres some confusion in the terminology... but what's new.
-Mindgame
03-12-2003, 05:09 PM
#8
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Join Date: Nov 2001
Location: In a house by the bay
Posts: 2,985
Swirl = clockwise or counterclockwise mixture motion. Swirl is defined as mixture motion during the "intake cycle". The direction of the port plays a big part in it as does the shape of the combustion chamber.
Tumble = mixture motion about the central axis of the cylinder (flush your toilet.... that's swirl..... tumble goes in the opposite direction). Tumble is dependent on the port direction.... ie., the highly downdraft race type ports (raised runner & flat valve angle heads) have good tumble characteristics. Again, this is a mixture motion described during the "intake cycle".... nothing to do with combustion.
Alot of the race head porters are using swirl meters to measure it. What would any of their measurements mean if this were a "combustion related" term? You guessed it, nada.
-Mindgame
Tumble = mixture motion about the central axis of the cylinder (flush your toilet.... that's swirl..... tumble goes in the opposite direction). Tumble is dependent on the port direction.... ie., the highly downdraft race type ports (raised runner & flat valve angle heads) have good tumble characteristics. Again, this is a mixture motion described during the "intake cycle".... nothing to do with combustion.
Alot of the race head porters are using swirl meters to measure it. What would any of their measurements mean if this were a "combustion related" term? You guessed it, nada.
-Mindgame
03-12-2003, 05:17 PM
#9
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Join Date: Aug 2001
Location: looking for a flow bench so Brook and I can race
Posts: 3,505
Originally posted by Mindgame
Swirl = clockwise or counterclockwise mixture motion. Swirl is defined as mixture motion during the "intake cycle". The direction of the port plays a big part in it as does the shape of the combustion chamber.
Tumble = mixture motion about the central axis of the cylinder (flush your toilet.... that's swirl..... tumble goes in the opposite direction). Tumble is dependent on the port direction.... ie., the highly downdraft race type ports (raised runner & flat valve angle heads) have good tumble characteristics. Again, this is a mixture motion described during the "intake cycle".... nothing to do with combustion.
Alot of the race head porters are using swirl meters to measure it. What would any of their measurements mean if this were a "combustion related" term? You guessed it, nada.
-Mindgame
Swirl = clockwise or counterclockwise mixture motion. Swirl is defined as mixture motion during the "intake cycle". The direction of the port plays a big part in it as does the shape of the combustion chamber.
Tumble = mixture motion about the central axis of the cylinder (flush your toilet.... that's swirl..... tumble goes in the opposite direction). Tumble is dependent on the port direction.... ie., the highly downdraft race type ports (raised runner & flat valve angle heads) have good tumble characteristics. Again, this is a mixture motion described during the "intake cycle".... nothing to do with combustion.
Alot of the race head porters are using swirl meters to measure it. What would any of their measurements mean if this were a "combustion related" term? You guessed it, nada.
-Mindgame
its all mindgame
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