The Stovebolt Site Forums The Shop Area Engine Shop Valve cover gaskets on SBC

Time for new ones on the 327 in Da Maus. Any advice re. gasket thickness, make/type of sealer, methodology, etc. before I go to the store, buy the first ones I see and slap em on? Christian

I usually get rubber rather than the cork ones... I've used thick ones and thinner, but never had a problem sealing with any of them. So I never got too picky about them.

Clean and dry the valve covers real well (good time to paint them, too, if needed), take a small ball peen hammer and gently flatten the flanges around the bolt holes. They get indented from being tightened down.

Then apply an automotive gasket silicone (like RTV brand) on the valve cover flange, let it sit a few minutes, then lay the gasket on the valve cover flange. You can push the bolts (don't forget the washers) up through the cover and gasket and they'll hold the gasket in place when you flip it over and put it back on the head. You don't need to tighten the bolts too much, but they should be snug. You can recheck those after driving a bit, I usually make them too loose.

Anyway, that's how I do it!

Put on aluminum valve covers to seal it up permanently,
Scott

After untold hundreds, maybe thousands, of valve adjustments on round track race cars, I've developed a few opinions. First, rubber gaskets don't cut it! They squirm around, and develop leaks, especially if the engine is run hard. I prefer good-quality cork gaskets. Fel-Pro is best IMHO. Use high-temperature RTV or better yet, 3M "Super Weatherstrip Adhesive" to glue the gaskets to the valve covers. (The NASCAR name for the adhesive is "Gorilla Snot") Don't apply any sealer between the gasket and the cylinder head. Use some spring steel "spreader bars" under the attaching bolts to even out the clamping force on the valve covers and prevent dimpling the covers at the bolt holes. These accessories are available at just about any parts store in the hotrod section. Mr. Gasket makes some good ones, but any brand is about the same. (These things were originally used on Corvair valve covers back in the 60's).

Snug the bolts until you feel all the slack go away, then tighten an additional 1/3 to 1/2 turn. I like star-type lockwashers under the bolts instead of conventional split-type lockwashers.
Jerry

I second the Fel-Pro cork gaskets - RTV is fine w/ me, hate harvestin that snot from the gorillas, they get grumpy

Bill

Thanks, you guys are a mine of info. It's awesome how you know everyflippinthing there is to know about the old truck game. And Jerry, you even make me feel better about living next door to a gorilla.

Already have aluminum M/T covers on the truck. Why do they seal better than steel? More rigid?

Sheet metal covers develop dimples at the bolt holes, which compress the gasket in one small area, and leaves long sections without enough tension. Cast aluminum won't distort that way. Chevy finally got it right with their late-model engines, with four bolts down the middle like the old Studebaker, and a captive O-ring in a groove, instead of a gasket. Unfortunately, you'd have to change cylinder heads to take advantage of the new design! I'm not even sure the late heads will fit the old block, but I don't think so!
Jerry