Leaking valve covers? A tip.

[kilrwail]

Here’s a tip for all of you folks who have leaking valve covers that you can’t seem to fix. If the covers are torqued too much, they can deform so that one or both of the ends is bent upwards. Replacing the gasket with cork or rubber won’t fix this. And tightening the cover even more certainly won’t!

The best and easiest way to fix the problem is to flatten the mating surface of the valve cover. It’s highly unlikely that the other mating surface on the cam box will have been deformed, so this should do the trick. Remove the offending cover and clean both mating surfaces thoroughly of old gasket material, oil residue, etc., using a razor blade knife very carefully. These are aluminum surfaces, so they can be scored if you’re not careful.

Buy some high quality, coarse emery paper (I used 120 grit), and tape a full sheet to a solid pane of glass or perfectly flat ceramic tile (which is what I use). Clamp the glass or tile to your work bench so it can’t move. Now slide the valve cover back and forth on the emery paper until it’s flat and shiny. Test the flattened surface by holding a true straight edge against it and looking for light leaking through the seam. When you’re sure the fit is as tight as can be, sand some more, just to be sure. Now you should have mating surfaces that are true and will not wobble when you put them together. Now you can use a new gasket of cork or rubber with confidence, torquing the hold-down nuts to a maximum of 7 ft-lbs. You’re done!

[joelittel]

Fantastic idea, thanks

[lglade]

That same technique can be used to flatten out an exhaust manifold too to ensure a better surface for sealing against the block.

http://www.dsmtuners.com/threads/true-y ... es.311991/

[sptcoupe]

The same technique can be used on the mounting surface of the oil pump when you have the motor apart again. Good way to get consistent pressure, and boost the pressure about 5-7 psi at the same time. No more low pressure "blinking lights" at idle on earlier cars with an oil pressure gauge.