Valve Cover Gaskets - cork or rubber?

So, I'm curious. Dad and I went to the auto parts store to look for some VC gaskets. All they had was rubber, but he insisted we should get cork. He said it was because the cork ones expand and seal better than the rubber ones?


So we headed home, and I pulled my VCs so I could clean/paint them, and found rubber gaskets.... that looked pretty new. However you COULD plainly see where they were leaking. Is he right? If so, why don't they sell cork gaskets at the stores (we went to Advance and NAPA).

Thoughts?

Rubber are better. Your dad is old. lol

Cork is better! I am old. lol

The steel core rubber ones are the best.

The rubber coated cork centers are the best and thats thats!

rubbers have kept me out of trouble before.... oh sorry wrong subject um i put rubber gaskets on mine when i got my chrome covers 4 months ago no problems yet

RTV is the best,

people always over tighten valve covers,.
cork deteriorates with heat and oil,.oil will eventually migrate thru the cork,.

Model T is the only car you need to have. all the others are just superfluous.

Nick

Alright then, rubber it is.

Oddly enough, the only place I found that sold cork valve cover gaskets charges like $10 more for them. What gives?

What gives? They are preying on the old timers that think cork is better....


And, for the record, I agree 100% with Nick. RTV and your old gasket is best.

What color RTV? Black?

Nick, I disagree, the Model A was a big improvemant.

I use Felpro silicone gaskets and I've never had a problem.

As do I, with aluminum aftermarket covers from Edelbrock. I even use the spreader bars to help clamp it down. but still see a few drips from time to time

Rubber gasketing got a bad rap <{(in olden times)}> because it used REAL rubber (from the plant) as it's major constituent.
Oil rots real rubber. Today, all 'rubber' is synthetic.

Ah. I see.


So what color RTV? Also, why keep the old gasket? When I took the cover off, you could clearly see where the oil had leaked past.

I use black RTV.

I use the old gasket *just because*. No real reason, just do. The RTV will seal where it leaked before anyway.

So RTV -> Gasket -> Valve cover.

Or Gasket -> RTV -> Valve cover (I assume this one? lol)

THIN coat of RTV, gasket, THIN coat of RTV

RTV is a gasket filler and adhesive.

I'll disagree. First step, get your valve covers completely clean on the gasket surface. Then, put them on a flat table (glass is good) to check to see if the flange is warped. If they are, you will never get them to seal. If bent, straighten. If good, run a THIN layer of RTV around the flange, then put the gasket on that. Let the RTV completely dry. When ready to install, clean the sealing edge of your heads, then put the covers on. No RTV between the gasket and the head. DON'T tighten too much! Just snug, then about an 1/8th of a turn. Just enough to pull the covers down on the gasket.

A new rubber gasket has been working just fine for years now.

RTV sucks.

jayoldschool wrote:

I'll disagree. First step, get your valve covers completely clean on the gasket surface. Then, put them on a flat table (glass is good) to check to see if the flange is warped. If they are, you will never get them to seal. If bent, straighten. If good, run a THIN layer of RTV around the flange, then put the gasket on that. Let the RTV completely dry. When ready to install, clean the sealing edge of your heads, then put the covers on. No RTV between the gasket and the head. DON'T tighten too much! Just snug, then about an 1/8th of a turn. Just enough to pull the covers down on the gasket.

Fair enough.

The covers aren't warped, thankfully. I checked that when I pulled them off.

Continuing paint prep tomorrow, hopefully will be finished and they'll be on so I can have my car back.

Another way (the best one) is to install a thin bead of RTV on the head and on the cover, set the cover on the head with or without a gasket (preferably with) and run the screws down barely finger tight. Let set overnight, then tighten screws (after RTV has been 'shaped' and has set).

No RTV with a rubber/silicone gasket. The RTV will act as a lubricant and force the gasket to be squeezed out when the valve covers are tightened down. Although the way jimbeau has describe his installation process it could work. For the sake of time constraints, working at a dealership, I never had the luxury of time like that. If you choose to use an RTV I would recommend.

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The only pia issue with RTV is that both surfaces have to be COMPLETELY clean, or it will not adhere, and oil will seep out.

off subject here but do i see the scooby doo mystery vanin gmtechs avatar??

Yes you do.

thought so my step mother loved scooby and i built a model of it for her birthday when i was young.

Quote :

The RTV will act as a lubricant and force the gasket to be squeezed out when the valve covers are tightened down.

Unless you do it like I said, and glue the gasket to the cover and let it completely dry. Works every time.

jayoldschool wrote:

Quote :

The RTV will act as a lubricant and force the gasket to be squeezed out when the valve covers are tightened down.

Unless you do it like I said, and glue the gasket to the cover and let it completely dry. Works every time.

With the luxury of time on ones side, methods such as those work perfectly every time, as you have stated.

I have time.