Cork versus Rubber Valve Gaskets

Mustang Jim

Founding Member
Nov 1, 2001
373
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New Jersey
I've developed a leak on one of my valve covers, so I will be changing the gaskets soon.

I see that there's the traditional cork gaskets and more modern (I assume) rubber gaskets. What are the advantages of rubber gaskets? They cost a bit more than cork, so I'm assuming that they seal better. Before I go and order a set of rubber gaskets, I would like to know what everyone thinks.

Thanks,
Jim
 
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2+2GT

10 Year Member
Apr 25, 2009
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Cork gaskets are more conformative. I use them on my 289HP, and they hold up just fine to repeated R&R. Of course, I have stamped steel valve covers. Here's the deal- If you have stamped steel covers, use cork, rubber ones just don't seal well on them. If you have cast aluminum, you can use the rubber ones.
 

Hack

15 Year Member
Mar 23, 2004
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Rubber gaskets last longer and seal better. Cork dries out, becomes hard over time, then cracks and crumbles. Rubber is also less likely to stick to parts and tear when you pull them apart multiple times. Rubber doesn't permanently deform like cork. Also rubber can be molded in complicated shapes - excellent 1 piece oil pan gaskets come to mind.

I've used both and rubber is by far superior to cork in my opinion. However you will spend more for good rubber gaskets compared to cork. The cheapest gasket sets typically have cork. If you are doing a cheap re-gasket and then selling the car you might use the cheap cork gaskets. They do work - they just aren't the best.
 

Mustang Jim

Founding Member
Nov 1, 2001
373
3
18
New Jersey
After removing my valve covers to repaint them, I put on a new set of cork gaskets and, after 3 months, they developed leaks. Granted, I bought the set for $5 at Carlisle. But, I thought they would have lasted longer. My last set lasted over a decade without so much as a drop of oil from them.

I found a set of rubber Fel-Pro's for $15 at Mustangs Unlimited. I don't expect to have to take the covers off very often, but I think I'm going to give the rubber gaskets a try. I hate leaks!

Thanks,
Jim
 

rbohm

SN Certified Technician
Apr 12, 2002
6,698
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tucson,az
Just so I understand, rubber gaskets DO NOT require gasket cement. Is that correct? Also, if I am to use cork, gasket cement should be used only on the gasket side facing the valve cover?

Thanks,
Jim

correct, rubber gaskets do not require sealant, however it is good to glue them to the valve covers with something like 3M weatherstrip glue. a few dabs in strategic locations will do nicely. and with the cork gaskets, you dont need sealant either, but again they should be glued to the valve covers as well, again 3M weatherstrip glue does real nice here as well. remember that while there is a fair amount of oil that gets up to the top of the cylinder heads, by the time it gets to the valve cover gaskets there is little pressure, so as long as the gasket is properly installed, the valve covers properly tightened up, and the gaskets in decent shape, there should be no leaks. over tighten the valves covers, especially the steel covers, or damage the gasket, and you will have leaks.
 

EP429

Member
Jun 30, 2007
120
1
16
Central Texas
it is good to glue them to the valve covers with something like 3M weatherstrip glue
Ive used this in the past and will never do so again. It is a chore to remove :bang: A dab or two might do okay, but don't get overzealous. I had a friend once who put a solid bead of this stuff around his valve covers, we had to use a crow bar to remove them :doh:
 
Ive used this in the past and will never do so again. It is a chore to remove :bang: A dab or two might do okay, but don't get overzealous. I had a friend once who put a solid bead of this stuff around his valve covers, we had to use a crow bar to remove them :doh:

in the future, try the Permatex mentnioned in my post. it's high tack to help hold gaskets in place. it kind of dries like bubble gum stuck to a table. i only put it on the valve cover side to hold it in place. thinner will easily remove it.