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Head Gaskets

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Garys1969RR

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When I pulled my 496 apart, it had copper head gaskets on there. And no O Rings. It did look like there is some red RTV like substance on there.
Every copper gasket I looked at requires O rings. So not sure whats going on there. Also wondering why copper works with Aluminum heads, while steel shim is not recommended. Cast iron, copper and aluminum all expand at different rates. But these heads were sealing fine, no evidence of leakage. I have used steel shim gaskets with aluminum heads before, and they sealed fine. Has anyone else had good luck using the steel shim type with aluminum heads? Thanks. Oh, these are the Stealth heads.
 
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Hmmm..... maybe somebody here knows more than I do on this (likely), but I don't see any obvious "thermal expansion" or "corrosion" issue related to using a steel shim gasket vs. a copper shim gasket.

"Maybe" the copper gaskets seal better because copper is more malleable (softer) so it can squeeze into head/block surface defects to make the seal better?

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I think the issue is, the different expansion rates between cast iron and aluminum. This stresses the gasket, I guess, causing it to eventually fail. The car manufacturers have had problems with that since they started using aluminum heads on everything. So they came up with the MLS gasket, which has several layers. Then these can slide across each other, without failing. Using the steel shim is a bit of a risk, although lots of guys have had success with them. Fewer miles, and mainly warm weather driving helps, I'm sure. I have had no problems with the 1 motor I used them on.
 
Cometic has perfected the mls gasket system. If your going to use copper you will get long life. The picture looks like they sprayed the copper with Hi tack made by permatex. Have no fear using copper.
 
snakeoil24 said:
Cometic has perfected the mls gasket system. If your going to use copper you will get long life. The picture looks like they sprayed the copper with Hi tack made by permatex. Have no fear using copper.
Click to expand...
Not that I plan on it, but are the copper ones re usable? I have heard they are, if in good condition.
 
snakeoil24 said:
Cometic has perfected the mls gasket system. If your going to use copper you will get long life. The picture looks like they sprayed the copper with Hi tack made by permatex. Have no fear using copper.
Click to expand...
Not that I plan on it, but are the copper ones re usable? I have heard they are, if in good condition.
 
A little off topic,
but I think many of the problems associated with any Head Gasket, are more related to sealing surface flatness and the finish applied than anything else ?
For example:
as mentioned the expansion rates between a cast iron block and an aluminum head are substantially different, MLS gaskets being superior in having layers to slide against each other to compensate.
But what it seems no-one ever pays attention to is for example Cometic's own recommendations for Block/Head surface finishes of 50ra or less to allow best Gasket layer adhesion to each ?

Many have used the Cometics on stock Blocks sporting the 50 year old factory finish with no reported problems ? or at least none reported? flatness then being the other key factor to sealing, and good clampload on a 17 Head Bolt Engine like a BB Mopar assisting.
just saying, and IMO...
When not so sure about deck flatness or finish ?
The most "forgiving" Head Gaskets are still probably the Composition style vrs any steel shim or mls.
 
Only reason I ask about the steel shims, is that I like to get a .035 quench distance between the head and piston. I have found they run better, and are less prone to detonation with tight quench. So if the piston is .015 below deck, then I use a .020 gasket. .010 below would need a .025 gasket. and 440 source has those . For a zero deck motor I guess I'd use the. 039 fel pro. Lots of choices here.
 
With that .039 compressed head gasket, what will that give you for static compression?

Mine is zero deck, .051 compressed head gasket and static compression is 9:96.1. Did I miss something on your build?
 
5.7 hemi said:
With that .039 compressed head gasket, what will that give you for static compression?

Mine is zero deck, .051 compressed head gasket and static compression is 9:96.1. Did I miss something on your build?
Click to expand...
I'll be right around 13 to 1 C/RATIO on this 512. That's with a 75 cc Stage VI head,
.005 positive deck height, flat top Icon piston, 4.5 cc valve reliefs, and a .039 fel pro head gasket. Where the piston ends up after decking the block, will determine which head gasket I use. What stroke crank and cc head are you using, 5.7?
 
80cc head with a 3.915 stroke.

Will your combo run pump gas or will it require something more?
 
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