A Better Head gasket?

Performance mods and Advanced Stroker discussion.
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Plechtan
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A Better Head gasket?

Post by Plechtan »

hrdp_0603_01_z+cometic_cylinder_head_gaskets+MLS_and_gas_filled.jpg
Actually the head gasket i would love to have, but of course they don't make a version for the 4.0 What is it you may ask? Well the best description i can come up with is a Stainless Steel O ring. The ring is .060" thick and has like 500 lbs of pressure in it. See the document below for a detailed description.
CometicPhuzion.pdf
So what is this all about? well we decided to go back to Bonneville, this time with a turbo. To get the 800hp we are looking for, we have to run around 30lbs of boost. Somehow we didn't think the stock head gasket would hold up under these pressures. I talked to SiXPAC , he is running a 350hp nitrous shot, and probably producing over 300 hp on the base motor. I'm guessing he is pushing somewhere around 700hp total. The Victor head gasket did not hold up. SIXPAC went to oringing the block and using a copper head gasket. It works, and maybe it would work for me, but i have an aluminum head and SIXPAC does not. Copper can be a pain in the but to seal around water passages.

I really like the idea of a seal that has some spring in it, if the head lifts, these things would probably maintain the seal. But Cometic does not make the gasket. I talked to Lee at Hesco, he suggested cutting a step in the block around the top of the cylinders and not to use a head gasket, just drop the seals into the step. That still leaves an issue with the water passages and general sealing of the head to the block. One suggestion was to counter bore the block for O rings, then use silicone on the other areas. Sounds like allot of machining. The other idea was to get a .050 thick copper gasket, and have the bores opened up for the metal o rings. I did some calculations, and the thin point of the gasket between the cylinders would be less than .200" I question whether the copper gasket could really hold the seals into position. So machining the block seems to be the best solution.

I did ask Cometic how much they would want to tool up to make a gasket for the 4.0, They said tooling costs would cost $4,500 So if we get 100 people to kick in $45 apiece for tooling, You would be able to buy it out of a catalog.

This is really cool stuff, and maybe if turbocharging becomes more popular there may actually be some demand for them .
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Peter Lechtanski
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Re: A Better Head gasket?

Post by GoMopar440 »

How would these gaskets help the average 4.x builder besides allowing for a lot of boost? Would the gaskets hold a tighter tolerance for getting repeatable crushed height numbers? I'm just thinking out loud here.

Machining the block for O-rings is an expensive option and this gasket looks like a much more economical solution for the DIY turbo guys. I can also see where it would probably help with high compression NA builds as well.

FWIW: I'm very familiar with the Cometic's reputation and wouldn't mind getting a high quality head gasket for my stroker build from them if they did make them. Especially if it could help the stroker community by helping to get more 4.x specific performance parts available.
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Alex22
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Re: A Better Head gasket?

Post by Alex22 »

Plechtan wrote: I did ask Cometic how much they would want to tool up to make a gasket for the 4.0, They said tooling costs would cost $4,500 So if we get 100 people to kick in $45 apiece for tooling, You would be able to buy it out of a catalog.
This is what's so nice about Cometic, If you want it and can pay, they will make it.
Plechtan wrote:

I really like the idea of a seal that has some spring in it, if the head lifts, these things would probably maintain the seal. But Cometic does not make the gasket. I talked to Lee at Hesco, he suggested cutting a step in the block around the top of the cylinders and not to use a head gasket, just drop the seals into the step. That still leaves an issue with the water passages and general sealing of the head to the block. One suggestion was to counter bore the block for O rings, then use silicone on the other areas. Sounds like allot of machining. The other idea was to get a .050 thick copper gasket, and have the bores opened up for the metal o rings. I did some calculations, and the thin point of the gasket between the cylinders would be less than .200" I question whether the copper gasket could really hold the seals into position. So machining the block seems to be the best solution.
Haisley machine makes a similar gasket to what you're talking about but for Cummins engines. The nice thing about Haisley's method is that a stock head gasket is used to seal the water, the fire ring is removed from the head gasket and a separate one piece ring is installed. Their gasket/fire ring combo uses a solid ring and depending on the application the receiver groove is cut into the head only (up to 80 lbs boost) and for high boost (80-100 lbs) half of the groove is cut into the head and half is cut into the deck of the block. I've machined a few heads and one block for this gasket using the BHJ tooling and it isn't too difficult, the setup is a bit tedious. The guys over at Haisley are easy to deal with, I'm not sure what they use for tooling but I've heard the gaskets are modified on a water jet so its possible a custom Jeep head gasket would be more reasonably priced from them. Indy cylinder heads came out with an aluminum Cummins head about a year so you can look up how well that style gasket works with an aluminum head.
http://haisleymachine.com/index.php?cPath=304_307

~Alex
The enemy of good thing is wanting something better.
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