Sounds like warped housing.

Posted by Joe on Sep. 15, 1998 at 12:27:05

In Reply to: Camshaft leak
posted by HAL on September 13, 1998 at 07:05:15

:I have a leak where my camshaft meets the flywheel housing that I can not stop. I have tried 2 gaskets, gasket sealer and nothing stops the leak. It only leaks when I shut the car off mainly after it has idled for a while.
:I originally thought as you are probably thinking that the rear main was leaking but when I take a rag and screwdriver up behind the crank flange it is completely dry in that area I also checked the clearance and only have .001 which should be good.
:Anyone have any ideas on how to stop the leak, I don't mind a couple drips but this is a small puddle. Thanks
Bob
If you have ever set up an engine after a rebuild and done the flywheel housing alignment using a dial indicator and the shims on the upper ears of the flywheel housing, you'll be surprised to discover how flexible the flywheel housing really is.
If you can, remove the engine, demount the flywheel housing one more time, and have the matching machined surface flattened.
The surface could be formally machined on a surface grinder at a machine shop.A cheaper method would be to go an engine rebuilder who uses a large "belt surfacer" which is bench or floor mounted to surface heads and other parts of engines to restore the mating surface to "truly flat" condition.These machines do a wonderful job of surfacing but of course can't make the surface flat very accurately with respect to some other surface as a machine tool can. (Not good for intake manifolds of V8 engines.) The belt surfacer would work well for this application though and would cost less than $10 to have the flywheel housing matching surface flattened.
The downside of this methodology is that the flywheel housings are already fairly thin at this section which lead to service cracks which people variously ignore or worry about.You don't want to remove any more material than is necessary to flatten the surface.
By dealing with the problem (flat surface) rather than plugging the leak at the camshaft necessitating it's removal, you can hopefuly effect a solution with a minimal amount of "resetting up" of the engine components.
Of course, if you're the persistant (and cheap) type like me and handy with a file or small handheld belt sander and happen to own a surface plate and some bluing, you can do this work yourself and save the $$.Of course you'll be tied up for several hours in the process so have your secretary hold your calls.
Hope this all helps,
Best regards,
Joe