DR 650 valve cover sealing technique?

So I have done my valve cover 5 times and it always weeps in the front left corner. I have decided I am done with it, that part of the engine will have some oil on it, life goes on. now here I am at work and I am having trouble getting a cover plate to seal to a heating block, mostly b/c the plate was made too thin and flexes withthe pressure. I am consulting with some gasket/seal guys and they had a method to try and I thought it also might work for the DR. The idea is to put a bead on the head, set the valve cover on it and let it cure overnight. Done right this should make a uniform gasket of the bonding material. Then tighten the bolts, (optional - slaughter some chickens to the gods) and hope it holds.

Anyone try this??


On a DR VC gasket I clean and lightly scuff the sealing surfaces of both parts and then I clean them again with acetone. Make sure to sop up any oil or anything in the area that could run or drip on to the parts. Then I just take a new gasket and hang it up by a wire. Then I spray it with ultra copper high temp gasket maker that comes in an aerosol rattle can. While it is still tacky I assemble that side with the screws ran in until they just touch plus about 90-180 degrees. Then I clean, scuff and spray the other side of the heads cover and repeat. After it has cured then I torque the fasteners.

Sometimes cover sealing problems are caused by high spots. Any little divot on the sealing surface will also have a high spot surrounding it. I take a good quality flat file and using the surface itself as a guide work it over the whole sealing surface. It's sometimes surprising what this turns up. You'll find high spots where bolts have been overtorqued and the threaded portion is actually pulled up slightly above the sealing surface.

Thanks. I'll have to try the file on the head. the bolts were overtorqued years ago when the shop replaced the base gasket (has leaked since). I have used a flat table and 600 grit on the cover, it's pretty flat.

On the sealer I got ahold of permatex tech support. I guess the technique of letting it partially cure is used for RTV gasket maker. He said for the valve cover I should use an anaerobic sealer (#51813). I was sealing a breather cover on a kohler 12hp last night and the black gasket maker said to finger tighten the cover, let it sit for an hour and snug it up

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now