Hey guys, I am wanting to be sure where to place the new small o - rings during a valve job on my 305. I know that the plastic umbrella goes on first,(for exhaust in this case) then does the small black o-ring go all the way down to top of umbrella seal OR does it need to be strategically placed at the lower notch on valve stem below "keeper?"

Thanks.

 

Lower groove on the valve stem, below the one that the keepers hook into.

You must compress the spring & retainer, slide the o-ring into it's groove, then the locks, then release tension on the spring. The o-ring will then seal against the inside of the retainer. It's kind of a pain in the ***, but that's how it MUST be done. Putting it in it's groove and then shoving the retainer down the stem won't work- the o-ring will be shoved out of it's groove and down further on the valve stem below the retainer where it won't do anything worthwhile.

 

Damon is correct. Just before the keeper goes on, the little "O" ring goes on the lower groove. It's a pain in the nuts if you have a spring compressor that can barely hold to compress enough to get the keeper on, and then you have to compress a little bit more to get the ring in the groove.

Some question the need for the "O" ring at all, it just reduces the amount of oil that the real valve seal has to shed.

 

Thank ya'll both.