Gasket cement or not on Cam Cover

One trick I learned from my Alfa mechanic for troublesome cam cover gaskets:

He'd use cement between the gasket and the cover only.

On smooth clean heads, he'd take a sharp pointed center punch and gently tap a line of tiny burrs about four inches apart down the length of the gasket contact surface to keep the gasket from being pushed outwards.

 

If your shop technique is good, then something is warped. Lay the cover on a large pane of glass and look for gaps. If it's the head itself you have a larger problem.


Ken

 

What car are we talking about?

 

Mike,

For cam cover gaskets, I've always used Hylomar. A very thin coating on both sides of the gasket seems to work well. Even on my old Jaguars, which are notorious for oil leaks, it seals up nicely and holds for a long time. Also, because it doesn't "set", it's easy to remove if you ever have to open the covers up again. You do have to watch the gaskets, though, as you tighten the cover as they can have a tendency to walk out from under the cover especially at the corners.

Hope that helps,
Steve

 

gore-tex tape has worked very well for me - 1968 colombo v-12.

http://www.daytonaregistry.com/originality/lgor.html

 

Asuming you've got a 3x8 engine:
Other than a matchead sized dab at the where the end of the gasket meets the cam seal/seal housing, DO NOT USE RTV.

BTW, Search is your friend, in this & the old fchat there are about a dozen threads on sealing cam covers.

 

We (Verell and I) used Hylomar and Ultra Black RTV at the o-rings. Here is a photo taken before we smoothed out the hylomar.

No cover leaks in over 2 years.
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All I did on my 77 3 years ago when I did the belts and checked the valves was to put a very thin coat of white grease on the head and nothing on the cam cover. The grease is so thin that you can't see it , I just wanted to make sure that the gasket did not stick to the head. So after 3 years no leaks. Enjoy the ride

 

Another vote for Hylomar / RTV dabs at the cam seals combo --- I use precisely the same approach with the exception that I prefer the Ultra Copper flavor of RTV due to its higher temp limit and better oil resistance.

Be sure to use a new gasket and clean the cover and head mating surfaces well.

Get friendly with Hylomar --- it's great stuff. I use it to seal all joints that aren't subject to high fluid or gas pressures. Although, the technical literature for the stuff says you can use it on head gaskets!

The best thing about Hylomar is that it never sets / cures. So, it won't glue the parts together like most gasket sealants --- this makes disassembly of the parts easy.

 

And, it won't cure into a solid chunk just waiting to clog an oil passage because I laid on a little too much.

 

Technicaly if the cam cover is flat and true, you should'nt have to use any gasket sealer. If it did'nt leak before and it leaks now then you have other problem. So make sure the cover is perfectly flat.

 

Theoretically, you are correct. But that also assumes that the gasket material is also flat and true. In reality, there are always minor imperfections on any surface. Using a thin coating of Hylomar to assure a good seal is not a bad thing; it is a prudent practice, and it works really well.

 

If you use Hylomar, get Permatex brand.

The Valeo hylomar has a solvent component that quickly evaporates. While the Valeo hylomar doesn't set up, it does get very very thick & won't flow once the solvent evaporates. It's ok for things like 2 bolt flanges you can quickly put together, but not for large gaskets. It gels before you can smooth it out on a long, complex gasket like the cam cover.

The cover doesn't have to be 'perfectly flat', it will flex a few thou if necessary, and the gaskets have some give, but a major bow or other deformation can be a leak source.

One way to check to see how well the cover lays down is to smear the mating head of the head with a thin coat prussian blue, then slip the cover down w/o a gasket & tighten all the nuts. When the cover is removed i'ts gasket surface should have a fairly continuous smear of prussian blue ie: no long continuous gaps.

I've sometime lapped a cam cover over a sheet of 400 & then 600 grit sandpaper on a flat surface to bring it back flat. A granite surface plate or piece of plate glass is ideal, but any flat surface will work.

Small discrepancies can be carefully sanded out with a long flat sanding block. Just be careful & lay the cover on something flat to make sure you're not sanding at an angle.