Teflon or Viton valve seals

Very interesting .

Centerline Products: VG129 Teflon Valve Guide Seal

Do they require a special tool to install ? Looks like a tube just the right size would do the trick.

Found this on the Jegs web site

Crane Cams Teflon valve stem seals provide maximum valve stem oil control. These seals wipe excess oil from the valve stem by means of a unique spring loaded wiper assembly, thus preventing unwanted oil from reaching and contaminating the cylinder. Machining usually required

Click to expand...

Comments I've found on line:
Requires Manganese Bronze valve guides (which Alfa has used forever), but the machined top is different from the OEM - Viton seal - version. Centerline supplies both the teflon seal and the special machined guides, or you can machine OEM guides to fit.

Teflon seals require very well polished valve stems, which is common on Alfa valves. They wipe oil vigorously, so they do not work well in iron head cars - almost no oil gets to the valve guide.

Popular on new ultra low emission engines because of extreme sealing.

Teflon is much harder than the viton seals. Used on Porsche's for some time. Can fail of the guides wear. Sometimes they break from poor installation.

Some hate them. Some love them. Most comments from big-block racers. Replaced at least yearly in normal overhaul, sometimes find broken ones.

Robert

I wonder if there is less friction from the Teflon seals ? It would be a small loss but it could add up to measurable number.

Looking at the Centerline site it seems to me if you buy the guides from them you have to buy the Teflon seals or maybe I am missing something.

FWIW, with industrial valve seats, softer materials generally seal better than harder materials but may have a shorter life. So Buna-N seals better that Viton, which seals better than Teflon.

I think both work well. I have pulled off green like new off old heads. just don't use the crap black guys that come in the gasket set. they seem to be only good for a year or so. The green or white should out last the engine.
I have used both. if I use center line guides I use white. and if I use stock type then I use green.

I have had a white fail on install once it would not stay on the guide. You have to take care on install that they go on straight. if they go on at any angle at all the guide seems to cut/scrape the seal and it will be trashed. the green seem to go on a bit easier.

Oil Seals

I only use the green viton seals. And I use them on both sides (in & exh) even on race heads. If you measure the installed height above the guide they are much shorter than Teflon seals. Important when heads are built for high lift cam clearance.

From the pics, the guides machined for the teflon seals are shorter than the OEMs.

But I tend to agree. I don't see any obvious gain to the teflon seals vs several issues that have to be addresses to use them.

Robert

I also do both sides. I almost forgot that alfa only did the intake.
almost anything I see has been done at lest once so I never see the OEM type with just seals on one side. even my first alfa (my 72 spider) had seals on both sides when I got it in the 80's