cometic head gaskets

[randy wilson]

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.

[Jeff Niceswanger]

Originally Posted by Ed Wright

^^^^^^^ Never heard of anybody using 75 lbs either.

Gulius always has us use 72 with lube Ed ,,,, All his motors are studded

[RICK W]

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.

[Ed Wright]

Originally Posted by Jeff Niceswanger

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.

[carl hinkson]

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.

[bry-war]

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

[gmeyer]

Thin coat of copper coat on all three pieces will fix the problem I have done it that way for a while now. greg

[BillK]

Originally Posted by bry-war

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.

[bry-war]

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

[BillK]

Originally Posted by bry-war

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