I just have a question regarding taking apart 3-layer metal tier HGs. I have a 79mm bore d16--with about 12.8:1 compression using a 0.030" Cometic HG. I wanted a little more compression--I have an old Cometic Gasket that was only used for about 2 hours, and a new one I haven't opened yet. The motor will be assembled this week--I just picked it up from the machine shop. I was thinking of trying it first with the "used" Cometic gasket. What is the method to go about doing this? Which of the 3 layers should be used? I was under the impression that I should use the middle layer---but I want to know if there are any problems with this, such as coolant or combustion leaks. Anyone who has some experience with this--please let me know, thank you, Jay.

 

why not send the un opened one back for a thinner one

 

I have been wondering about this myself.

 

That is an interesting idea. The place I bought it from only stocks the 0.030" Cometics I believe. I suppose I could get my money back and get a thinner one from somewhere else. What other thicknesses does Cometic make? Also, if I do decide to keep it and split it apart--do you have any idea which is the best layer to use?