The Stovebolt Site Forums The Shop Area Engine Shop Umbrella seals

I'm going to put umbrella seals on the intakes on my 848 head .does anybody know which ones fit? sbc or maybe 302 f**d ?

A goods question for your local FLAPS.

The valve stem diameter is 11/32".
I prefer the stock quad/O' ring seals, but Chev and Ford did used this diameter umbrella seals in some application.

A valve in a typical auto engine, driven a couple hours a day
over an 8 or 10 year period will have to slide up and down in
its guide some where very close to a billion times in its life
time. Hot bone dry metal to metal contact just isn't gonna cut
it. Some oil has to reach the guide and putting an
umbrella over the guide in addition to the factory
engineered O'ring seal is asking for early valve
failure in my opinion. And every one is entitled to
their own opinion.

Ok, re-wrote it to include all the valves, that should
make everyone happy.

Denny Graham
Sandwich, IL

well you wouldn't need them on the exhaust valves.
exhaust valves usually don't suck excessive oil down the stem like intakes sometimes do.

I will do away with o ring seal if I put the umbrella seals on and yes intake only . Still would like to know which ones to ask for at the flaps

I just brought a valve with me and the pencil-necked, pimply-faced, minimum wage, well-meaning young man was even able to find what I needed. I really miss the days when the counterman always seemed to know more than most of his patrons. Nowadays the people that they hire around here are just there to tell you that "we don't carry that part", in order to get you out of their face. BTW, I don't call them pencil necked, pimply-faced, minimum wage until after they try to tell me that they don't carry a part that was used in every Chevrolet from 1937 thru 1992. Actually I have never said any of that out loud.

I found some seals that fit . Looks like the smoking problem might be solved.

As general rule, if it smokes on start up, its the valve seals or valve guides. If it smokes while driving, the rings are worn or cylinders are worn or a combination of cylinder problems. I really doubt your new seals will stop 100% of the oil to the stems as Denny suggest, no seal will do that. Since the seal rides the stem, the umbrella will actually catch some oil vapor and divert it to the stem while the outer part of the seal sheds off the bigger drops of oil.
Inside a moving valve spring being feed by a drip oil system, theres not a whole lot going on anyway with oil splash.

Be sure to check valve seal to head clearance, you don't want to smash the seal with your high lift cam profile Just be sure they don't hit at full open (lift).


Joe

So Joe H, Are you saying the umbrella seals are just a band aid fix vs. just replacing factory seals? I was thinking about using them in my 265 V8 that is using oil, does not smoke, perfect compression.
Thanks
Jim

I have always preferred the factory seal over the umbrella.
Once installed correctly the factory seal never fails, unless the engine sits for a long long time and the seal dries out and cracks(I've only seen this once).
My experience with umbrella seals is that they harden and crack prematurely no mater what you do.

I use only a positive type seal on heads I build. With the proper clearance, I see no problem with adding newer type seals. Mopar used a lot of the umbrella seals with no problem. Umbrella type seals are just diverters, the stem and guide opening are still exposed just as if the seal wasn't there.

If you are having smoking problems on start up, grab hold of each valve spring / valve assembly and see if you can wiggle them side to side or forward / backwards. If you feel any movement at all, the stems or guides are worn. New seals might help for a while, buts its not a cure all.