1960s Valve cover sealant

[Nomcalister]

I'm replacing my valve cover gaskets with Flo-Pro cork gaskets and was going to use Permatex 82180 Ultra Black Maximum Oil Resistance RTV Silicone to adhere the gasket to the valve cover but wasn't sure if I should use the Black, Red or Gray silicone from Permatex. Any thoughts??

[Clewisiii]

I can tell you that I used black. And a tube of black came with my complete engine gasket kit.

The only others I used was high heat copper on my exhaust manifold.

And non setting blue on my carb base.

[Chopper1942]

The main difference besides color is the temperature rating.

Max temp ratings are:

Red = 350°
Black = 400°
Gray = 600°

For valve covers any should work just fine. Make sure the valve covers are straight especially at the hold down bolt holes. Apply a small bead to the gasket and spread to a thin layer on both sides of the gasket. Set the gasket in place on the valve cover and install the valve covers. TORQUE THE BOLTS TO SPECIFICATIONS. Overtightening will split the gaskets and bend the valve covers.

[TJ Hopland]

You really should not be applying 'a bead' if you are using gaskets.   A bead is generally what you use if you don't have a gasket.  What I have done for years with reasonable success is just smeared the RTV on both sides of the gasket then when it was tacky assembled it.  While you are waiting for it to get tacky make sure its hanging not laying flat on something, you don't want it to stick to your bench.

I do like the ultra black.  No reason to go with anything harder for a valve cover.  It will just make it that much harder to get apart and clean up the next time.  The higher temp has no effect on if its gonna leak or not. 

In the olden days where you had to take the valve covers off regularly to adjust valves you would just put the stuff on the cover side to hold the gasket in place both when it was installed and when you had to remove it for adjustments. Cork in theory doesn't need any sort of sealer.  If you put sealer on both sides its gonna be harder to get off if you have to get it off for any reason so make sure they are going to stay on for good before you do both sides.  Like are you messing with the distributor when you may need to know where the compression stroke TDC is?     

Like Larry said the biggest thing is to make sure they are flat especially around the bolts.  If they are not if you have random stuff laying around your garage you can usually improvise some sort of flat backing material to get under the bad area and tap it back down flat.  Wood can even work and can be really nice because you can cut out a notch for the edge to lay in.   

[Nomcalister]

Thank you for all the advice. I have been told by multiple people to only put sealant on the valve cover side so that next time I take them off they won't be stuck on the heads. Of course I don't plan on having to take them off again for a long while but just incase I guess.

[6262]

According to Permatex you should use a gasket dressing instead of Permatex 82180. Or is my interpretation of #10 wrong?

https://www.permatex.com/the-ten-most-common-gasketing-mistakes/

[Chopper1942]

I use several different types of gaskets sealers. It all depends on the condition of the surfaces to be sealed.

If both surfaces are machined: If it uses a gasket, I use Permatex High Tack gasket sealant to hold the gasket in place and help seal any very small imperfections in the sealing surfaces. It remains tacky and can be disassembled without having to destroy the gaskets and grind off the sealing surfaces. Works great for valve cover gaskets, thermostat gaskets, etc.  On disassembly, the High Tack can be cleaned off the gasket and sealiing surfaces with lacquer thinner.

Rubber gaskets require a different sealer.

If both surfaces are machined and uses a gasket but there are damaged areas of the sealing surfaces: I use a skim coat of RTV on the areas with the damage or if there is a gap between two parts, like a timing cover and oil pan.  This fill the void that the gasket may not be able to seal.

If both surfaces are machined and do not use gaskets: Cleaning is the most important issue. Surfaces must be clean, no oil residue, or damaged surfaces for the best results. Only use a plastic scraper to clean off the old gasket material. Lacquer thinner also helps. Depending on the application, either RTV or an anerobic sealer is used. Use which ever the OE specifies.

With either product, apply a continous 1/8" bead (more is not better: excess can come loose and plug up oilpump pickups) along the center of the sealing area and around each bolt hole. If there is a seam where 2 parts meet, apply a small amount to fill the seam.  Assemble while the sealer is still wet. Read the direction about cure time. Most take about 24 hrs to fully cure. Then you can fill with fluids.

RTV cures by air. Anerobic will stay liquid indefinitely. It cure by lack of air when the parts are assembled.

The secret to all of this is cleanliness and proper assembly. Always torque the fasteners to OE specifications. This is especially important with gaskets. Over torquing causes more gasket failures than being loose.

Something I used to do on thin valve covers was to make a metal tab that went around the bolt hole and about 1 1/2" on either side of the bolt. This spread the load and prevented distortion of the valve cover.

I guess this is more than his queston about what color to use, but this is actually a very complex subject. If you have questions, go to the Permatex website and get some information on using their products. But, it can be confusing. So many different products for different applications. You can always call their tech line if needed.

[Lexi]

Larry, always a pleasure and an education to read your posts! Clay/Lexi

[Chopper1942]

Thank you Lexi. I try to keep it as simple a possible, but sometimes I really need to go farther with a discussion. I really don't want to scare someone away from attempting to do their own repair work or diagnosis and I don't like to be long winded, but if someone needs more info, and I see it in a post, I will try to go deeper into the subject.

[Lexi]

Thank you Lexi. I try to keep it as simple a possible, but sometimes I really need to go farther with a discussion. I really don't want to scare someone away from attempting to do their own repair work or diagnosis and I don't like to be long winded, but if someone needs more info, and I see it in a post, I will try to go deeper into the subject.

Makes perfect sense. Often it is better to know why one has to do something a certain way rather than just be told to do it without any qualifiers. Qualifying a response should answer a ton of other questions and in the end save time and effort. Your replies do that, almost like you have plucked them from a Service Manual you are writng, (sign me up). Clay/Lexi