Teflon vs. Viton valve seals

[oil pan 4]

There for my 11/32'' valve (Staineless steel) and .530'' valve guide cast iron heads.
It will have a no hotter than a 180 thermo, Mobil 1 oil, wet sump oiling, no valve stem cups, single spring with a spirl damper, .511'' lift, top engine speed of 6500 rpms, forced induction (TT's), direct port fuel injection (some fuel contact with intake valve stem), most likely be run a little rich, it should only pull about 20'' of vaccume and have a low $ engine crank case evacuation pump.
Teflon is said to be for race engines and viton is the better stock replacement.
What do you think I should run???
Viton or Teflon?
I have been to the Viton web site and seen all its specs when used as O rings and pump seals.
Teflon is teflon I use those seals all the time on hyd system seals to gas turbine compressor stage seals, many uses.

[wantmorepower]

I am NOT the expert in sealing materials technology. I do know that Viton is used where high temperature and high pressure sealing is required. Viton is also a very good choice of material with oils.

One of my old jobs was refurbishing industrial plate pack heat exchangers. Typically we would find that the standard NBR gasket material was inadequate for high temp and high pressure applications. On these occasions we would upgrade the gaskets on these units to Viton.

So I am not sure if Viton is better than Teflon valve seals but i do know that Viton is a superior gasket material for high temp, high pressure sealing.

It would also seem to me that Viton would offer better conformity to the vavle stem thus providing better sealing.

[wantmorepower]

Found a little bit about Viton.

No more plain rubber

"Just as important as the design of a seal is the material thereof. Ordinary nitrile rubber was used for decades it's cheap, easy to mold, and has sufficient life as long as it doesn't have to endure temperatures of over 200250 degrees F. Wait a minute, where are you going to find such a cool environment inside today's hot running engines? Nowhere, so nitrile is seriously obsolete. Unfortunately, some off-brand manufacturers supply it for late model applications even though it just won't last.

The next step up is polyacrylate (or "P.A.," as they call it in the gasket trade), which can take 350 deg. F. Silicone has the highest temp resistance (480 deg. F.), but it's not very tough. The ultimate is Viton, DuPont's name for a very hightech (and expensive) fluorocarbon material that's practically bulletproof, is impervious to just about any chemical, and can withstand 450 deg. F. for a long, long time. As the previously quoted tech advisor told me, "Almost all late model valve seals are positive and made of Viton, which may be any of several colors. They may have annular grooves on intakes to provide oil control, and sometimes spiral grooves on exhausts to give the guide a metered amount of lubrication."

If you're wondering why all the auto-makers didn't go to Viton years ago, the answer is cost. How much of a difference can there be in the prices of some little rubber parts? A lot. If you assign nitrile a cost factor of one, then polyacrylate would be two, silicone five, and Viton 20! That big a difference made some import makers come up with seals that are more metal than expensive fluorocarbon. About this the gasket engineer said, "The all-Viton type of positive seal common on domestic engines can deflect and expand enough to accommodate an oversize stem. But the kind that's often found on imports with the metal shell and just a small sealing element can't expand as much, so you could get into trouble with an oversize stem."

All those synthetic rubbers look and feel the same, so the only way to be sure of getting the right stuff for the application is to buy O.E. or brand name aftermarket. But there's a further caution: I've heard reports that even O.E. may not be what you expect some Japanese car companies have specified lower quality parts for the replacement market than for the assembly line. While that's not common, it's enough to bias my purchasing decisions toward quality aftermarket brands. Wherever the labor-to-parts ratio is about a million to one, it's downright foolish to use anything but the best.

I'll conclude with a couple of miscellaneous points. One, you may balk at the price of those seals that have the metal valve spring seat and stem seal in combination. But this is no place to scrimp. And, two, always use a plastic installation tip to prevent the keeper grooves from tearing up the new seal. "

[wantmorepower]

Alot of times race stuff is the all out best but is only really made to last for "a few runs". Isn't up to snuff for us that drive our stuff day to day.

But I know where you are coming from... when you are in there you want to put in the absolute best you can afford and do it right.

[zlexiss]

Teflon and Viton are both highly resistant to solvents and oils, and both withstand high temperatures well.

Viton is a little more elastic (rubbery) than Teflon, which might make it better for seals.