The 440 and Pesky Valve Covers

[cv70chall]

I'm approaching my wit's end. Help!
I've settled on a set of date correct OEM valve covers- had them on for over 2 years- and I continue to have issues with the passenger side always seeming to develop a leak. Tried cork, cork with steel inserts- even composite. Getting tired of the smoke and burning oil smell.
Does anyone have a solution that works? (without having to weld the covers to the block lol)

 

[pschlosser]

Presuming these are the stamped steel oem-style valve covers, I can offer some insight from my own experience on a 440 big block.

Mine were bent. When the bolts are over tightened, it stretches the bolt opening in the valve cover in a way that keeps it from making a good seal. These become mounded, or dimpled, by the force of the bolt.

Inspect the "flatness" of the inner edge of the valve cover that mates with the gasket. Throw a 12-inch straight edge across there to confirm its pretty darn flat between one bolt hole and the next.

In my case, the bolt holes were dimpled, and would bottom out the gasket before the straight edge (between the bolt holes) could press the gasket enough to make a good seal. The straight parts were still straight and pretty flat, except for the mounds around the bolt holes.

I used a block of wood, a hammer and appropriate tool to tap the valve cover metal (the dimple around the bolt hole) back flat again. When installing them again, I took care to not over tighten on fresh gaskets and they have held up for 8+ years without a leak.

The photo depicts a bent or dimpled valve cover bolt hole that can hinder the cover's ability to squeeze the gasket against the head.

 

[moparlee]

Presuming these are the stamped steel oem-style valve covers, I can offer some insight from my own experience on a 440 big block.

Mine were bent. When the bolts are over tightened, it stretches the bolt opening in the valve cover in a way that keeps it from making a good seal. These become mounded, or dimpled, by the force of the bolt.

Inspect the "flatness" of the inner edge of the valve cover that mates with the gasket. Throw a 12-inch straight edge across there to confirm its pretty darn flat between one bolt hole and the next.

In my case, the bolt holes were dimpled, and would bottom out the gasket before the straight edge (between the bolt holes) could press the gasket enough to make a good seal. The straight parts were still straight and pretty flat, except for the mounds around the bolt holes.

I used a block of wood, a hammer and appropriate tool to tap the valve cover metal (the dimple around the bolt hole) back flat again. When installing them again, I took care to not over tighten on fresh gaskets and they have held up for 8+ years without a leak.

The photo depicts a bent or dimpled valve cover bolt hole that can hinder the cover's ability to squeeze the gasket against the head.
View attachment 105312

What type of gasket are you using and do you use any kind of gasket sealant?

 

[pschlosser]

Mine were some kind of dark fibrous pressed material. Not cork, but not rubber, either.

 

[Daves69]

Not only check / flatten the valve cover, you might also check the head with a straight edge.

This SB head has a raised area that didn't get reworked properly (ground/filed flat) from the factory.........

FWIW, Back in the day cork gaskets and brush on gasket sealer usually took care of the stock VC leaks. Put 'em on, let 'em set overnight. They worked well until they got brittle over time.
A PITA to clean it all off later!

Also make sure you don't have excessive blow-by issues and your PCV system is working.

Trichloroethylene was a great degreaser for the metal surfaces.
Not sold to the general public these days I believe.........

 

[Cuda Hunter]

That RTV gear sealant does the job. I don't like any of the other RTV's. They won't work.

I've used some 8 or 9 different valve covers over the years. I thought they all leaked and smelled.

 

[MoparCarGuy]

As others have mentioned...
1. Check steel valve covers for dimpled bolt holes and straighten those, if necessary.
2. Inspect the cylinder head for problem areas in the casting. You may find small paths due to the cast iron's porosity that are allowing oil to seep through. Seal any of those paths or pores with Permatex Form-A-Gasket #2 gasket sealer which will not harden. The Mopar Gear Sealant above will also seal the cast iron rails of the cylinder heads.
3. Use Moroso Perm-Align Valve Cover Gaskets 93055. They are rubber with a steel core but are pricey at over $60/pair.

 

[Ele115]

They have to be straight as an arrow. They suck. That's why you always saw Mopars with aluminum valve covers, even cabs and police cars.....they were thick and didn't warp. Get the rail as straight as you can, and OPTIONAL: from the underside, dimple it upward (away from the head casting) a tiny bit so it pushes down and flattens around the bolt hole when you torque it. If you over tighten it, you'll be starting over.