RTV on Valve Cover Gaskets

[money pit]

Does anyone use RTV on their cork valve cover gaskets? If so, do you use RTV on the valve cover and the engine surface? I have aluminum valve covers and I can't get them to seal. I'm using quality cork gaskets and I don't over tighten the bolts. Are there special bolts I should use with the aluminum valve covers? Thanks

 

[6PKRTSE]

Does anyone use RTV on their cork valve cover gaskets? If so, do you use RTV on the valve cover and the engine surface? I have aluminum valve covers and I can't get them to seal. I'm using quality cork gaskets and I don't over tighten the bolts. Are there special bolts I should use with the aluminum valve covers? Thanks

First make sure your bolts are not too long and bottoming out in the hole before the tighten down on the valve cover surface. I glue my gaskets to the valve covers with RTV or weatherstripping adhesive and use Vaseline or grease smeared on the valve cover to cylinder head surface, so when removed the gasket doesn't stick to the head. Many times the gaskets are still reusable.

 

[Mopar Mitch]

Along with proper and equal clamp load (never over-tightening!), make certain the surfaces are flat and without casting flash. Some cylinder heads have casting flash. Some aluminum valve covers have lined ridges... and they may not be pressing properly to the gaskets... possibly requiring slight trimming of the gasket to be pressed/compressed correctly... there are many different valve covers out there... so be aware of this matter. You shouldn't need any RTV... the gasket does the sealing... not the chemical. RTV could be used for attaching purposes... but let it dry 24-hours before clamping; quick-drying contact adhesive is preferred.

Also, there are low-quality grades of cork-rubber from off-brand companies... you pay for what you get.

Cork-rubber is compressible about 50%. Rubber is NOT compressible... it distorts when squeezed (properly up to about 30%)... too much and it'll split apart; rubber gaskets should always be installed DRY.

Note: I'm a former applications engineer from a major well-known gasket company.

 

[money pit]

First make sure your bolts are not too long and bottoming out in the hole before the tighten down on the valve cover surface. I glue my gaskets to the valve covers with RTV or weatherstripping adhesive and use Vaseline or grease smeared on the valve cover to cylinder head surface, so when removed the gasket doesn't stick to the head. Many times the gaskets are still reusable.

I'll double check the length of the bolts. I did replace them. What do think about using studs instead of bolts? It may look funny but I wonder if it would work.

 

[money pit]

Along with proper and equal clamp load (never over-tightening!), make certain the surfaces are flat and without casting flash. Some cylinder heads have casting flash. Some aluminum valve covers have lined ridges... and they may not be pressing properly to the gaskets... possibly requiring slight trimming of the gasket to be pressed/compressed correctly... there are many different valve covers out there... so be aware of this matter. You shouldn't need any RTV... the gasket does the sealing... not the chemical. RTV could be used for attaching purposes... but let it dry 24-hours before clamping; quick-drying contact adhesive is preferred.

Also, there are low-quality grades of cork-rubber from off-brand companies... you pay for what you get.

Cork-rubber is compressible about 50%. Rubber is NOT compressible... it distorts when squeezed (properly up to about 30%)... too much and it'll split apart; rubber gaskets should always be installed DRY.

Note: I'm a former applications engineer from a major well-known gasket company.

I'll try the adhesive. Any recommendation on the brand of gasket? Thanks

 

[Mopar Mitch]

I'm partial towards Fel-Pro... as I worked for them for 30 years... and they have always used hi-quality cork-rubber. Victor gaskets also use hi-quality cork-rubber.

 

[MoparCarGuy]

The Moroso Perm-Align gaskets can eliminate leaks due to the gasket itself but cannot make up for head issues. Check your cylinder head surfaces for pathways for oil. The iron's porous casting can leave "micro-craters" which can let oil bypass the gasket. If you see a questionable spot, wipe some Permatex 80007 Form-A-Gasket #1 Sealant on the area and let it harden. The Permatex will seal the iron's pores.
Let us know what you find.

 

[Chryco Psycho]

The reason Mopar always used steel valve covers is they will conform to the far from flat rail the cover sits on , the problem with alum is it will not flex & conform so sealing them can be nearly impossible , it would have helped if the factory heads were machined flat where the valve cover seals . Studs can be difficult also as the angle of the studs on the lower bolts can cause the fastener to interfere with the cover .
If you overtighten the bolts the cover will crack , I have seen numerous broken covers .

 

[money pit]

I'm partial towards Fel-Pro... as I worked for them for 30 years... and they have always used hi-quality cork-rubber. Victor gaskets also use hi-quality cork-rubber.

Thanks. I think the last gaskets were Fel Pro.

 

[money pit]

I'll double check the length of the bolts. I did replace them. What do think about using studs instead of bolts? It may look funny but I wonder if it would work.

It looks like the length of the bolts is okay.

 

[money pit]

The Moroso Perm-Align gaskets can eliminate leaks due to the gasket itself but cannot make up for head issues. Check your cylinder head surfaces for pathways for oil. The iron's porous casting can leave "micro-craters" which can let oil bypass the gasket. If you see a questionable spot, wipe some Permatex 80007 Form-A-Gasket #1 Sealant on the area and let it harden. The Permatex will seal the iron's pores.
Let us know what you find.

I'll check the surface of the head. the Moroso gaskets are pretty pricey but may be worth it.

 

[chargerdon]

In my experience aluminum valve covers are always hard to seal!! Lack of flexing like Chryco said is one problem, another is i had a set of aluminum Edlebrock brand big block valve covers and i noticed that the lip where the gasket goes is way narrower on them than on the stock valve covers. I tried everything and never could get the one on the passenger side to seal and the drivers side was difficult also. Threw them away and had no issue with the stock steel covers. They were an inexpensive swap meet set...they looked beautiful but...

 

[money pit]

In my experience aluminum valve covers are always hard to seal!! Lack of flexing like Chryco said is one problem, another is i had a set of aluminum Edlebrock brand big block valve covers and i noticed that the lip where the gasket goes is way narrower on them than on the stock valve covers. I tried everything and never could get the one on the passenger side to seal and the drivers side was difficult also. Threw them away and had no issue with the stock steel covers. They were an inexpensive swap meet set...they looked beautiful but...

I'm going to try a couple of things that MoparCarGuy recommended. if that doesn't work, I may switch back to the stock valve covers. Thanks

 

[73Machine]

You mentioned you're using aluminum valve covers but failed to mention what brand and also what engine it is for. The reason that matters is I too had a problem with my valve covers for my 340 with an Air gap intake. The intake runner sits up just high enough to not let the covers sit flat on the head. What I ended up having to do was actually double gasket it problem was then solved.

 

[money pit]

You mentioned you're using aluminum valve covers but failed to mention what brand and also what engine it is for. The reason that matters is I too had a problem with my valve covers for my 340 with an Air gap intake. The intake runner sits up just high enough to not let the covers sit flat on the head. What I ended up having to do was actually double gasket it problem was then solved.

I'm not sure of the brand of the valve cover (Mopar Direct Connection). I can send a picture. The engine is a 1974 360. I have a performer intake manifold. Stock cylinder heads. Thanks

 

[73Machine]

No problem, helping each other is what the hobby is about. I sandwiched RTV between both gaskets then evenly clamped them.

 

[i_taz]

Can't hurt to use the Ultra Black oil resistant Permatex RTV 82180...

 

[Mopar Mitch]

Consider the Fel-Pro Performance "Cork-Lam" valve cover gaskets, set #1646... double thickness (.313"), hi-grade cork rubber with a steel center core.... retains its shape and easy to remove/reinstall. Its the only ones I use... lifts the valve up slightly for better rocker arm clearance; seals great! As others have said, you may have to trim the gasket slightly as different covers/castings have different shapes.... I've had to do this with my cast aluminum Edelebrock small block valve covers. Also, consider using studs instead of the small short bolts... the studs are a positive locator... bolts can bottom out and not provide the proper clamp load. Cork-rubber always conforms better than just rubber. No need for any chemicals such as RTV (which you want to avoid unless only applied slightly to the cover.... and then dried 24 hours before clamping and running the engine.

 

[money pit]

Consider the Fel-Pro Performance "Cork-Lam" valve cover gaskets, set #1646... double thickness (.313"), hi-grade cork rubber with a steel center core.... retains its shape and easy to remove/reinstall. Its the only ones I use... lifts the valve up slightly for better rocker arm clearance; seals great! As others have said, you may have to trim the gasket slightly as different covers/castings have different shapes.... I've had to do this with my cast aluminum Edelebrock small block valve covers. Also, consider using studs instead of the small short bolts... the studs are a positive locator... bolts can bottom out and not provide the proper clamp load. Cork-rubber always conforms better than just rubber. No need for any chemicals such as RTV (which you want to avoid unless only applied slightly to the cover.... and then dried 24 hours before clamping and running the engine.

Do you know if these gaskets are available at Jeg's or Summit Racing? Thanks

 

[money pit]

The Moroso Perm-Align gaskets can eliminate leaks due to the gasket itself but cannot make up for head issues. Check your cylinder head surfaces for pathways for oil. The iron's porous casting can leave "micro-craters" which can let oil bypass the gasket. If you see a questionable spot, wipe some Permatex 80007 Form-A-Gasket #1 Sealant on the area and let it harden. The Permatex will seal the iron's pores.
Let us know what you find.

I put a thin layer of the Permatex 80007 on the entire surface of the head. The whole surface looked pitted, more around the bolt holes. I also ran a tap through all the bolt holes. There was a lot of crud in the holes. I also used the Permatex high tack to secure the Fel Pro cork gasket. Thanks for your help.