Cometic "no-seep" installation method?

[Blazer406]

Of all the posts I have read on Cometics being installed on our Buicks.... I see a very high percentage of people that have had seepage problems with the Cometics...... What I want to know..... is who on here has installed them without seepage problems (water or oil)..... and what special tricks did you do when you installed them?

I am curious of who was successful and what was done.

Was the head surfaced? ..... if so... any particular surface finish?
Was the block surfaced? ..... if so ... any particular surface finish?
Were you running head bolts or studs?
What heads were you running?
What did you torque the head bolts to?
Did you use a spray like halomar inbetween the different layers?
Did you use seal tabs in the oil?

Hopefully this will help myself and others on this board in the future.... on what works...

 

[EightSecV6]

The biggest problem with Cometics is the machining process. You need to make sure your machinist or vendor cuts the deck of the head and the block to the a surface RA of 50 or better. You wont have any seepage between the layers due to the stainless center being mirror smooth. You can lightly dust the outer layers with Hylomar for insurance. We have installed hundreds of these and while there may be a problem child every now and then, there is a very small percentage that have seeped water.

 

[WiskeyJack]

Oil?

from where would they leak oil? Even though I have owned a GN now for 8 years I only have rebuilt a Buck 350 and have no experience with the V6 but did have mine rebuilt. It now has oil leaks I can't find or relate to valve covers and after running it if you open the hood fast there is steam coming off the heads. Coolant leaks were explained as common problems with Cometic gaskets but didn't know anything about oil.

 

[Blazer406]

from where would they leak oil? Even though I have owned a GN now for 8 years I only have rebuilt a Buck 350 and have no experience with the V6 but did have mine rebuilt. It now has oil leaks I can't find or relate to valve covers and after running it if you open the hood fast there is steam coming off the heads. Coolant leaks were explained as common problems with Cometic gaskets but didn't know anything about oil.

Cometic Thread

Not sure..... but I read it on this thread....

I still would like to know what torque people are using with ARP head studs....

 

[FastRegalWE2]

You can lightly dust the outer layers with Hylomar for insurance.

Which Hylomar product?