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Old 06-18-2017, 01:43 AM   #11
randy wilson
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Default Re: cometic head gaskets

I only go 70# on a small block with ARP lube, and when I use them over, I always use copper coat. I've never blown a cometic. Will copper coat help you? Don't know, but may be worth a shot.
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Old 06-18-2017, 02:18 PM   #12
Jeff Niceswanger
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Default Re: cometic head gaskets

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Originally Posted by Ed Wright View Post
^^^^^^^ Never heard of anybody using 75 lbs either.
Gulius always has us use 72 with lube Ed ,,,, All his motors are studded
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Old 06-18-2017, 03:12 PM   #13
RICK W
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Default Re: cometic head gaskets

It is studded and I torqued up to 85 with oil on threads, still seeping. I have never had a block machined this rough always smooth. I had composition gaskets in it before. Seems strange that I believe the owner before me used cometic gaskets. Will have to go back to regular gaskets.
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Old 06-18-2017, 04:39 PM   #14
Ed Wright
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Default Re: cometic head gaskets

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Originally Posted by Jeff Niceswanger View Post
Gulius always has us use 72 with lube Ed ,,,, All his motors are studded
I use 70 with lube. But, Gulius would know. If I could afford it, I would have one of his instead of my home made engine.
And, the surface finish, Cometic told me I need a smooth finish. Those rough ones like composite gaskets better.
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Old 06-18-2017, 11:27 PM   #15
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Default Re: cometic head gaskets

If the block was plate honed its best to go with what was used for hardware and torque during the plate honing procedure if it was plate honed to achieve good ring seal.

Studs do to the fine thread seem to distort cylinders more then bolts from what I have seen.
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Old 06-18-2017, 11:55 PM   #16
bry-war
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Default Re: cometic head gaskets

I have a big Chevy from Schmidt that failed between 5-7 due to cutter marks using cometic gaskets. Only posting to say that composite is my only fix but why is the cutter pattern not the same between bores. It's as if the block machine was cutting at angle (side to side) making most of the between bore deck verticle pattern and others a bit more /// direct between bores. Is there a standard for deck tooling path? I just assumed parallel to crank. Sorry if I'm hi-jacking.
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Bryce
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Old 06-19-2017, 09:53 AM   #17
gmeyer
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Default Re: cometic head gaskets

Thin coat of copper coat on all three pieces will fix the problem I have done it that way for a while now. greg
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Old 06-19-2017, 11:40 AM   #18
BillK
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Default Re: cometic head gaskets

Quote:
Originally Posted by bry-war View Post
I have a big Chevy from Schmidt that failed between 5-7 due to cutter marks using cometic gaskets. Only posting to say that composite is my only fix but why is the cutter pattern not the same between bores. It's as if the block machine was cutting at angle (side to side) making most of the between bore deck verticle pattern and others a bit more /// direct between bores. Is there a standard for deck tooling path? I just assumed parallel to crank. Sorry if I'm hi-jacking.
Thanks
Bryce
Bryce,
The finish should be the same across the entire deck surface including between the bores. Here is an Olds block I just finished.
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Old 06-20-2017, 09:21 AM   #19
bry-war
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Default Re: cometic head gaskets

Bill,
That is a fantastic finish. Here's the Steve Schmidt finish and the difference in pattern and where the combustion escaped.
Pretty terrible. Thanks for sharing.
Bryce
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Old 06-20-2017, 10:05 AM   #20
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Default Re: cometic head gaskets

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Originally Posted by bry-war View Post
Bill,
That is a fantastic finish. Here's the Steve Schmidt finish and the difference in pattern and where the combustion escaped.
Pretty terrible. Thanks for sharing.
Bryce
Good grief that is pretty terrible for a modern shop. Wonder if someone wasn't paying attention
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