x2 on the umbrella seals. They were really the improvement over the O rings when rubber was real rubber. So if you had some worn valve guides, and were willing to remove the springs with the head in place, you could install the umbrella seals and get a little better control over the oil intake down the valve stem.
These days the rubber is not what it use to be and deteriorates pretty quickly. In my experience, the O rings are unfortunately in the same boat. I have taken a couple of dozen 235s apart over the years and truth be told, to this day, I have never found a single intact O ring on any of them. Then the Teflon seals came on the scene.
With a good fit between the guide and Valve stem, the o rings get the job done for as long as they are intact. After that, your burning a little bit oil.
Last edited by Dragsix; 07/03/2020 4:10 PM.
