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Old 05-13-2011, 03:46 PM   #1
10.5
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Default Head gasket thickness

What is the thickest head gasket that you've ever seen used, and did it work well? Cometic style...
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Old 05-13-2011, 04:38 PM   #2
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Default Re: Head gasket thickness

A friends car with .120 compressed and a f2.
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Old 05-14-2011, 01:03 AM   #3
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Default Re: Head gasket thickness

Randy, I've had .093's on my car with no gasket issues. But I'm not as fast as alot of these fellas.
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Old 05-14-2011, 01:29 AM   #4
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Default Re: Head gasket thickness

I've used a pair of .100 thick Cometic once to lower compression on a motor that another builder had his hands in and made a mess of. Was supposed to run on pump gas and they had it over 13:1. Worked out fine. Motor still made very good power and would run on pump gas like it was supposed to.
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Old 05-14-2011, 11:19 AM   #5
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Default Re: Head gasket thickness

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Originally Posted by Smitty275 View Post
I've used a pair of .100 thick Cometic once to lower compression on a motor that another builder had his hands in and made a mess of. Was supposed to run on pump gas and they had it over 13:1. Worked out fine. Motor still made very good power and would run on pump gas like it was supposed to.
When you say used a "pair"...does that mean .100 on each side, or .200?

I've got a piston-to-valve clearance problem after cutting some O-rings out of some heads. I stacked two .040 gaskets together, and still have the exhaust valve touching the piston. Was wondering how much head gasket that I could get away with.
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Old 05-14-2011, 12:18 PM   #6
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Default Re: Head gasket thickness

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Originally Posted by 10.5 View Post
When you say used a "pair"...does that mean .100 on each side, or .200?

I've got a piston-to-valve clearance problem after cutting some O-rings out of some heads. I stacked two .040 gaskets together, and still have the exhaust valve touching the piston. Was wondering how much head gasket that I could get away with.
You notch the pistons .
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Old 05-14-2011, 10:53 PM   #7
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Default Re: Head gasket thickness

Your going to need a minimum of 80-100 thou clearance, so if your still touching with 80 thou of gasket(s), I dont think extra thick ones will give you enough.
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Old 05-15-2011, 12:06 AM   #8
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Default Re: Head gasket thickness

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Your going to need a minimum of 80-100 thou clearance, so if your still touching with 80 thou of gasket(s), I dont think extra thick ones will give you enough.
You dont need .080 clearance. If you have control over the valvetrain .050 is a good rule of thumb and less will work if you know exactly what the valves doing

To the op question you shouldnt solve this problem with head gaskets. Take the pistons out and make the valve notch bigger for the clearance. Running a really thick gaskets gonna kill combustion chamber efficency. Touching up the piston is pretty simple and easy to do
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Old 05-15-2011, 10:21 AM   #9
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Default Re: Head gasket thickness

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Originally Posted by shawns engines View Post
You dont need .080 clearance. If you have control over the valvetrain .050 is a good rule of thumb and less will work if you know exactly what the valves doing

On the exhaust side?

You go boy!

I think if you have enough control over the valvetrain to allow you to run the exhaust side that tight, your not making any power....N/A anyway! LOL
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Old 05-15-2011, 10:35 AM   #10
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Default Re: Head gasket thickness

Quote:
Originally Posted by 10.5 View Post
When you say used a "pair"...does that mean .100 on each side, or .200?

I've got a piston-to-valve clearance problem after cutting some O-rings out of some heads. I stacked two .040 gaskets together, and still have the exhaust valve touching the piston. Was wondering how much head gasket that I could get away with.
how much was cut off the heads ? if you stack up 080 and did not have any room on Ex side then you cut more then 080 off the heads ? if it was just 080 you should be were your were before the hair cut on your heads . sound s like you may have had every little room on the ex side before ,when checking your piston to valve with one head gasket did you check with a shorter push rods ? the best way to go at this is fly cut the pistons try not to go past 060 on the head gaskets if you check all holes with out lash you should get away with 070 on the ex side
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Old 05-15-2011, 11:03 AM   #11
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Default Re: Head gasket thickness

If they are touching with (2) .040 gaskets your just gonna have to cut the valve pockets... Your gonna lose a ton of compression by putting that much gasket on it.... And what is the intake centerline of the camshaft?
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Old 05-15-2011, 06:33 PM   #12
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Default Re: Head gasket thickness

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Originally Posted by David.Powell View Post
If they are touching with (2) .040 gaskets your just gonna have to cut the valve pockets... Your gonna lose a ton of compression by putting that much gasket on it.... And what is the intake centerline of the camshaft?
2x and or try moving the camshaft and recheck clearance, or reduce rocker ratio.

Last edited by team hyperactive ez555; 05-15-2011 at 06:35 PM.
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Old 05-15-2011, 07:14 PM   #13
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Default Re: Head gasket thickness

well you could move the cam or you could go small rocker ratio . why ? if this thing was a runner before why screw with it .there must be a machine shop around you that can fly cut the pistons ? i do not know what rockers you have on it. but fly cutting the pistons may be a cheaper way out . i cut piston all the time $10 a hole. if your at O deck i would try to stay under 060 for a head gasket you pick up some CR when the heads were cut they should be CC for volume so you know were your at for CR. so i would not worry about the loss of CR with the thicker head gasket but more to do with the squish
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Old 05-15-2011, 07:22 PM   #14
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Default Re: Head gasket thickness

Quote:
Originally Posted by Warp Speed View Post
On the exhaust side?

You go boy!

I think if you have enough control over the valvetrain to allow you to run the exhaust side that tight, your not making any power....N/A anyway! LOL
LOL. doesnt even make enough power to turn the water pump.. Slightly of topic warp speed but if you would care sharing what is the typical valves clearances you shot for in your engines. And do you measure them static or account for piston/rod/block and valvetrain growth and valve train deflection and use that figure.

This post is not offensive just interested in how other designers calculate their figures
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Old 05-16-2011, 11:58 AM   #15
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Default Re: Head gasket thickness

I just had to have my domes cut off my pistons to reduce com. and I am going from 0.42 gasket to a 0.60 to help reduce com.
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