Just wondering if anyone else has had issue with valve stem seals on small blocks ?? Engine has about 75k miles since rebuild, is stock 360. Have one cylinder that fouls up the plug in about 400 miles. Compression all around is good, and can see a bit of blue out the back on start up. Hence thinking that the seals are all hard and or broken. Pretty cheap fix, $50 for seals and valve cover gaskets. Figure this should keep the car running for a while yet, without pulling the engine and rebuilding, or replacing . . . engine runs great when I replace/clean that one plug !

Cheers,

Mark

Am I reading this right, you replaced the seals & no change? might be a well worn guide that was missed on rebuild but I'd suspect a leaking intake gasket on that side letting oil into that cyl. On the guides a person can put an intake seal on the ex valve (intake seals have a bigger umbrella)

I just changed the seals on one cylinder of my rebuilt 318 with less than 5K miles on it. (it was a purchased rebuilt).

I had the same issue as you, one cylinder oil fouled. When I was changing the seals I found that the top of the intake valve had a sharp edge and I believe that it cut the seal when it was install.

I cleaned up the top edge and installed a new seal with the tube like tool that came with them.

No more oil fouling.

:-)

Nope. I have not replaced anything ... just going to replace the seals. I have left it alone for a while, and finally gotten to the point I will do something on it, so I don't have to change the plug every 400 miles. Pretty sure I am just looking at the stem seals, sure there is probably some wear in the guides/valve stems, but heck, it does have 75k miles since the rebuild.