Viton or Teflon? Valve stem seals

[TdiRacing]

Which is the better valve stem seal? I have looked all over the net, and want to know what the pros are using?

Green is Viton right. White teflon?

[Jeff Alton]

viton

[3.2 CAB]

As far as I know, the viton seals seem to be in a lot of applications.

[304065]

White Teflon = bad, they actually seal the stem too well? Bob at Anchor-Atlantic did my heads and cautioned against the use of the white seals.

[HawgRyder]

If the application calls for the white Teflon seals, I usually take a small triangle file and cut a tiny notch in the seal part (inside rim).
Then I install with the notch up.
It gives just enough oil into the guide to lubricate without allowing smoking.
Bob

[TdiRacing]

So the viton ones are the way to go I guess for the 911 valve guides?

[Rot 911]

Originally Posted by TdiRacing

So the viton ones are the way to go I guess for the 911 valve guides?

That is what John Walker recommended and used when he rebuilt my heads.

[kenikh]

Teflon seals too well. My engine was just torn down and teflon were used. The valve guides were crap and I didn't even know it since the Teflon seals masked the issue by not letting any oil by. I got lucky; the teardown was elective and if this hadn't happened, there would have been major problems in the future.

[hcoles]

also... I read on one of these valve seal threads.. that the Teflon were easier to install and that's why some shops like to use them...

[Tompickett]

My head rebuilder put in Teflon seals--should have them replaced with Viton?

The heads are still off, how much trouble is it to replace the seals?

[hcoles]

hey.. guys do we tell Tom to replace or leave the Teflon in?

[Flieger]

Go Viton.

I would rather pay a little more in the increased oil consumption and put up with some smoke than over heat a valve due to lack of oil. The head could fall off and rattle around in the combustion chamber, messing the whole cylinder up.

If it leaks a little oil, what's the big deal? You will eventually flush the oil by adding a little at a time and you will be aware that your top-end is getting lubrication.

[911pcars]

Originally Posted by Flieger

Go Viton.

I would rather pay a little more in the increased oil consumption and put up with some smoke than over heat a valve due to lack of oil. The head could fall off and rattle around in the combustion chamber, messing the whole cylinder up.

If it leaks a little oil, what's the big deal? You will eventually flush the oil by adding a little at a time and you will be aware that your top-end is getting lubrication.

A little oil is fine. Any more and the heat (on the exhaust side) oxidizes the oil until you have a fur ball-size chunk of carbon in the exhaust port and on the valve head. More than this and the oil starts to migrate into the combustion chamber. However, you'll also notice the smoke from the tail pipe at this point.

Either one of the above scenarios isn't preferable. We seldom have a choice and instead should deal with the existing condition. Lube to the top end is good, but oil leakage into the chambers via the valve guides is hardly a consistent method of distribution.

Sherwood

[Flieger]

I was being slightly fascetious (sp?).

New Viton seals installed properly will not leak and will only allow a proper anti-wear film to penetrate to the valve. They will not seal "too well" as the Teflon does and the manganese bronze guides sometimes appear to.

The Viton may wear quicker, at which point some oil will leak past the seals after sitting.

I think it will only be a "healthy" amount of oil that gets past while the seals are in spec and if the engine is exercised enough and in the proper way.

[911pcars]

"I was being slightly fascetious (sp?)."

so noted.

Sherwood

[Henry Schmidt]

We always use Teflon. We have engines that have lasted 260K miles using the old tried and true. I have seen too many broken Viton seals to feel they are worth the risk. Plus I hate an engine that smokes.
Heat is the enemy of valve stem not valve stem seals.
When we are building high HP turbos we often run special guides with no seal but that is a different animal.
Bottom line is that either seal will work and work well. Flip a coin .

[Tompickett]

Great--I am thinking I am going to stick with the TEFLON since:
1.) my local mechanic also uses them and says that properly installed they work quite well...
2) I am reluctant to pull perfectly good seals out of the heads after the fact I think that might introduce additional opportunity for mistakes.

Thanks to everyone for the help!

[Determined]

I used Teflon on my 3.2L rebuild, but be careful during installation.

Alex

[TdiRacing]

So what is the trick to installing the teflon seals as opposed to other ones? Special tool or what?