Inlet manifold gaskets

Shaun

Supporter
Ok so trial fitting my inlet manifold, I have the gaskets for the induction side, missing the small cork? ones but when I looked at various sites including summit racing quite a few said not to use the cork gasket but to use RTV silicon instead?
Thoughts on that appreciated
Cheers
 

Dave Bilyk

Dave Bilyk
Hi Shaun, when I trial fitted my current manifold (I changed to EFI) I found that the gap was too small for the cork. The cork prevented the inlet manifolds from sealing on the main manifold gaskets. In my case the gap was only a couple of mm so I then used RTV instead. My original manifold didn't have that problem, but I can see that in the 'v' of the heads, a small dimensional change in the cyl head spacing can make a large difference in the gap left where the cork gaskets go. If you trial fit without the cork, and the gap is less than say 75% of the cork thickness, then you might find issues in compressing the cork enough to seal the manifold gaskets, so I would go for RTV or find some thinner cork. If the gap is 75% to 90% of the cork thickness, you could use the cork, but I would always go in with feeler gauges to satisfy myself that it's all going together properly as the manifold is tightened down. You may need to use RTV anyway to seal the ends of the cork.
 

Shaun

Supporter
Cheers Dave that's top advice, I need to shave a tiny amount off the manifold to clear the rocker covers then I can check the gap. I also have 2 sets of manifold gaskets but no cork parts!!!
Thanks
 

Tim Terry

Supporter
Shaun, I am firmly in the "no cork gaskets in front or rear" camp. I use the Right Stuff from Permatex. It's very easy to use and seals nicely. If any spills/spooges out during installation, just wait for it to dry and trim with a razor blade. Right Stuff advertises you can install parts and put into service right away (as in minutes after a water pump installation).
 
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