white valve seals

[Mike the mechanic]

Great new forum!!

Can anyone tell me the difference between the white valve seals and the regular brown/gray ones?
Thanks!

[ChrisBennet]

The Viton ones are brown/grey ones. The white ones are Teflon.
-Chris

[Doug Zielke]

FWIW.....
The expert machinist who re & re'd my 3.0 cylinder heads, advised *not* to use the white Teflon seals. He installed the brown seals as supplied in the OE gasket kit.

[Wayne 962]

Hmm, I haven't heard that these *ever* leak. Either one should be fine...

-Wayne

[Doug Zielke]

Originally posted by Wayne at Pelican Parts
Hmm, I haven't heard that these *ever* leak. Either one should be fine...

-Wayne

The white ones *don't* leak. That's the problem.
The OE seals are designed to allow a specific amount of oil past the seal to lubricate the guide and valve stem.
(This, from a specialist with over 20 years of cylinder head rebuilding experience.)

[ChrisBennet]

My "head guy" says he sees accelerated valve stem wear from the Teflon seals. Steve Weiner advises using the Viton ones except for the exaust valves on Turbos.
-Chris

[Mike the mechanic]

Alot of good info here! So Chris, what does Steve reccomend for the exhaust valves on turbos?

[ChrisBennet]

Originally posted by Mike the mechanic
Alot of good info here! So Chris, what does Steve reccomend for the exhaust valves on turbos?

Oh sorry, he recommends the Teflon for the Turbo exhaust valves.
-Chris

[88911coupe]

Just curious as to why it would be recommended to use the Teflon on the Turbo exhaust side. Possibly heat related...

[ChrisBennet]

Originally posted by 88911coupe
Just curious as to why it would be recommended to use the Teflon on the Turbo exhaust side. Possibly heat related...

The material used for valve stem seals has varied from rubber,
to Teflon, to silicone, and finally to Viton to achieve the
best oil control, heat tolerance, and longest life. These
Viton guide seals, while more expensive than their
predecessors, do an excellent job of keeping oil consumption
to a minimum. We have installed a LOT of these guide seals and
so far, not one given any troubles. Same for our phosphorus
bronze guides. When installed and used properly, end of
problems (at least with these). We only use Teflon on the
exhaust guides on Turbos due to the major heat stresses that
these engines place on exhaust valves and the additional oil
that Teflon seals allow down the guides helps lubricate an
item that sees temperatures over 1400 degrees. 935's had
special drillings in the heads and guides to do similar
things.
Use Viton seals in confidence with any naturally aspirated 911
engine!

[TimT]

OK a heads up:

The Viton seals are fine, they really wont leak until the valve guides are way worn, nor do the teflon guides.

The are some issues with Viton valve guides though. The Viton o-ring come mounted in a bakelite "cap" that fits over the valve guide.

I have seen a set of heads come back from being rebuilt where almost every bakelite viton holder was fractured by poor instalation.. That engine blew smoke. We didnt see the problem with the valve seals until we broke the engine down on our dime.

The teflon seals are much easier and forgiving to install.

[tbitz]

Can the intake valve seals be replaced with the engine in the car with the intake runners removed?

It looks like I have a leak. Check out this thread for pictures:

http://forums.pelicanparts.com/porsche-911-technical-forum/99187-oil-leaking-intake-valve-seat-serious-post701392.html#post701392

[osidak]

I had EBS redo my heads and they came back to me with the teflon seals installed. I also purchased a gasket kit from them that came with the other seals.

I left the teflon ones in there. Should this be something I try to replace or leave it well enough alone

[kwikt 911]

I had my heads done by Ollie's and they too installed the teflon seals. Hmmmmmm!


Kevin
72 911T/E

[osidak]

Any one know the answer to this

>>I had EBS redo my heads and they came back to me with the teflon seals installed. I also purchased a gasket kit from them that came with the other seals.

I left the teflon ones in there. Should this be something I try to replace or leave it well enough alone<<

Thanks

[TimT]

Im not sure what the question is.... I havent seen a gasket kit that comes with teflon seal, every one I have bought has the viton seals.

For some time the recommended valve seals have been the teflon ones.
I have bought gasket kits, and not used the included viton seals, and have bought the teflon seals to use..

Both types of seals work....

[ChrisBennet]

The guy who does my heads (all he does are heads) recommends the Viton.
-Chris

[TimT]

Has anyone read the new excellence?

Its back to viton... after years of pushing the teflon seals its back to the rubber ones....... go figure....

[Wayne 962]

Walt at Competition Engineering uses Teflon. I haven't heard any really good arguments for or against either one. I think it's an minor issue at best...

-Wayne

[movin]

For me the issue is longevity under all conditions and that's where teflon wins. Additionally, I seem to remember that the Viton seals were suspect in starving the guides for oil especially in the Carrera series. Properly installed teflon seals allow sufficient oil to lubricate the guides. If I'm off base here please let me know.