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Best Way to seal valve covers on a 440?

Believe it or not, I've had the best luck with cork gaskets + a little silicone. I'm running iron heads & stock valve covers. The heads aren't smooth & the valve covers do bend from over-tightening. Cork seems the most forgiving (I've tried a BUNCH over the years). I do have to change them every time I adjust the valves though.

If you don't have to adjust your valves, then just silicone would be the best sealing IMO (sloppy, but conforms perfectly to the head/valve cover). Aftermarket, non-stamped valve covers would help for sure. And as one of the other guys mentioned, make SURE your valve cover bolts aren't too long & if they are use washers. I've been down that road too.
 
Valve covers are studed and have no worry about bottoming bolts out. Use cork and rubber with no sealer and Moroso covers no leaks.
 
I made a discovery a number of years ago that has eliminated any and all issues with sealing.I've
held a Journeyman's ticket in the trade for almost 40 years. I couldn't figure out why, when GM started sealing valve covers with RTV they were stuck so hard you bent the valve covers prying them off, yet when we put them back on with the same RTV, they'd leak. Why paper and cork gaskets would stick so well you chiselled them off, yet if it had been apart the gaskets would fall off.
The answer lies in how we cleaned the surfaces. We washed with solvent, hosed off with water and blew dry with air. The surfaces looked clean and dry, but the reality is that we were leaving behind a film of oil. Paper and cork would seal reasonably well, but still sweat. The gaskets were never"stuck" like the factory seal. RTV won't tolerate any oil at all and it always leaked.
It was the availability of brake cleaner made from dry cleaning chemicals that changed everything. Used correctly, it removes all traces of oil. Once we started using that we were able to replicate the factory seal, no matter what material, or what brand, everything sealed properly.

It has to be used properly. Don't spray it on a rag and wipe things off. Doesn't get it out of the grain. Spray it directly on the surface and follow right behind with your air hose so it really gets into the surface. Do this at least twice. Then don't touch them with your hands at all. Apply your gasket or sealer. TORQUE TO SPEC AND LEAVE IT ALONE.
Guaranteed leak free joints with original tin covers on the original cast surfaces.
 
I used to have the same problem. Now I only use cast aluminum covers, as they are more rigid than stamped steel factory ones, and remain flat at the gasket surface. Then you RTV the gaskets to the COVER ONLY. Install them on the head, tighten slightly, and let the sealer begin to set up. After a few hours, I tighten them most of the way. Then when you remove them, the gasket stays on the cover! (Hopefully) You can put a thin coat of oil on the head at first, to make sure the gasket doesn't stick. This method also applies to covers that have been welded together from aluminum plate, like I have on my 496. Don't know much about this type of cover, but the welds are a work of art! Since I've been doing it this way, they never leak, and come apart easily. I have pulled the covers off 5 or 6 times, and they always seal great! Over and over again!
 
I've had real good luck with the blue moroso gaskets...no RTV and no more leaks. I do, however, have aluminum covers that have machined flat 3/8" thick flanges which helps I'm sure..I used to run the cast black mopar covers and the flange surface had circular indentations and ridges and I couldn't get a good seal no matter what I tried..
 
Lots of different ideas.I have never had a cork gasket continue to leak, patience is the key...they have to oil soak so they swell.Same reason wine bottles with corks are stored on their side.
Silcon gasket to valve cover.
 
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For over 45 years, I clean with acetone, apply Indian head, snug fit, let dry. As long as the head surface is smooth and the valve cover STRAIGHT, never ever a leak on anyone's engine.
 
Silicone is great stuff if used correctly. Its not a one type fits all apps and less is often better than more. When used as a gasket should always be wider than its height.
Over torque any form of gasket and it will fail.
 
dodge68charger said:
just wondering how you guys went about sealing yours so they dont leak. Bought the black gaskets and thinking about gasket sealing both sides.



How often did you tighten them After? Thanks
Click to expand...
I designed my own valve covers and had a local machine shop make them for me. I used a 1/2 inch flange and have never had any leaks.
DSC_9660 (Large).JPG
 
I wouldn't seal both sides, you will have a hard time getting the covers off, and the gaskets will get torn up on removal, and you will have sealant stuck to the head, and the valve cover. Just put sealant on the valve cover, so the gasket stays with the cover.[/QUOTE]
 
I've never needed to do anything different:
Valve cover flange has to be flat and not cracked at the areas the washer contacts them (rather common these days). Also assumes you know the holes are good and the valve cover flange isn't touching the intake manifold anywhere when it's in place without the gasket. It it does - you need to figure out if the gasket will provide enough distance to clear it AND still be compressed.
Head flange and cover MUST be totally clean and grease and oil free - even oil from your skin. I use brake clean and shop towels after it's all cleaned off to make sure.
I use the stock cork - it's soft enough to squish into the cast surface and seal well.
Glue the gaskets to the cover using weatherstrip adhesive. Leave the head flange side dry. No RTV or sealant on the head side.
Install the cover, finger tighten the bolts. I only use a 1/4" drive wratchet so it's harder to overtighten then. Over-torqing will bend the cover - not compress the gasket more. Tighten the center two lower bolts, then the lower corners, then the top two center bolts.
At this time I tap it twice with my fist... But I'm guessing that's just me, not technically anything you must do...lol. Using the above method I've run the same valve cover gaskets for years, checking lash a few times with no leaks.
 
excellent point about the valve cover contacting the intake manifold.
...they almost always do on aftermarket intakes
 
Stock covers and heads I’d use some good thick cork gaskets. Glue them to the valve covers with yellow weatherstrip adhesive after you make sure the covers are straight. I always take a small ball peen and hammer the holes on the underside of the covers to knock them flat or even out a touch. Black RTV will also Work. I never glue both sides because I like to be able to easily pull the covers. I suppose if you don’t intend to pull them you could glue both sides.

Superformance are great on cast alum covers and machined aluminum heads, thats what I use on my 511. Wouldn’t dream of using them on stock stuff though, that’s not the intended usage.
 
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To go along with all the great above ideas; I use a 1/4”ratchet also but I put my hand right on the head of ratchet and go pretty tight. Can’t hardly go over-tight that way.
 
oldbee said:
To go along with all the great above ideas; I use a 1/4”ratchet also but I put my hand right on the head of ratchet and go pretty tight. Can’t hardly go over-tight that way.
Click to expand...

That's how I do it too...lol
 
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