The Stovebolt Site Forums The Shop Area Engine Shop Stovebolt valve stem seals

We've discussed various ways to control oil consumption through the valve guides on our engines, and the current problems with the quality of the umbrella seals that are available these days. Here's an alternative, and it's a drop-on fit- - - -no machining required.

www.ebay.com/itm/224857681590

The .562" diameter of the seal fits the OD of a stovebolt valve guide (9/16") with just enough of a snug fit to stay put, and the garter spring on the sealing surface provides good oil control without starving the guide for lubrication. Just don't double up and use ANY other type of seal along with it, including the little O rings that fit under the split locks on the second groove on the valve stems.

Here's another sneaky trick- - - - -it's easy to damage the sealing surface of the lip of a "positive" stem seal as it's being pushed over the split lock groove(s) at the top of the valve stem. The large diameter soda straws that convenience stores provide with their "big gulp" drinks are just about the right size to slip over the top of the valve stem and protect the sealing lip from the sharp edges of the lock grooves. Warm up a short piece of the the plastic straw with a hair dryer to make it slip over the valve stem smoothly.
Jerry

Funny, just took this pic tonight and was going to ask about it as I know I've seen threads on here about starving the valve of oil. I assume the same as you posted was installed on my head? And I should remove the rubber o-ring?

Thanks,

Mark

I'd use one or the other, but not both. The problem with the O ring up at the split locks is that valve guide wear will still cause the engine to use a little oil. The seal at the top of the guide does a better job of metering just a tiny bit of oil flow to keep the valve stem from seizing up or wearing the guide out in a hurry.
Jerry