Viton vs Teflon valve seals

Which do you use?

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MomsDuster

MomsDuster

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Reason for asking is, the 440 source site sells reduced diameter Teflon valve seals in double valve spring applications. Quick web search has a bunch of horror stories on installing these seals. I personally have only installed Viton and had zero problems. Curious to the general consensus of you all.
 
Teflon is soft and wears out quickly compared to Viton. Viton is a high temperature compound that is impervious to oil and lasts a very long time and does not become brittle.
 
There is a Viton seal application for double springs, I'll se if I can dig up the part number.
 
It sounds like 440 Source has a bunch of Teflon seals they need to unload. LOL
 
Teflon seals are much less forgiving than the viton seals. 65'
 
pittsburghracer said:
Teflon seals are also known to wear valve stems out leading to more leakage.
Click to expand...
Let me ask you this, from all that I’ve read so far I’ll need to cut down the guide to fit the smaller seals. Is that something a DIY person such as myself can do in the garage? Or will it require a machine shop?
 
MomsDuster said:
Let me ask you this, from all that I’ve read so far I’ll need to cut down the guide to fit the smaller seals. Is that something a DIY person such as myself can do in the garage? Or will it require a machine shop?
Click to expand...
And with a little more research I found my answer.
 
If the heads are cut for PC seals absolutely go with Viton.

I don't use either for double springs on 3/8" stock valve guide tops that I don't want to cut. I am not that big a fan of PC seals and I like the guides to get a little more oil.

One particular set of double springs I use has a .700" id on the inner spring, so using umbrella seals is obviously out unless you trim them into disk.

So years ago I just started using square profile, high temperature (400F), silicone o-rings that have a .637" od that I buy from McMaster-Carr McMaster-Carr

I assemble the o-ring right against the top of the guide and once the engine is rotated the o-ring slides up the valve stem whatever the lift of the cam.

Since oil comes sliding down the valve stems from above through the two gaps in the valve keepers it really isn't an issue letting the o-ring ride on the stem to deflect the oil.

I run my 499" street engine with this setup and have no issues using the o-rings.

Tom
 
I’m all for people using whatever parts and processes they’re having good luck with.

That being said, unless I’m told specifically to not do it, just about any heads I get thru the shop that don’t already have the guide tops set up to accept common aftermarket seal sizes(typically .500 or .530), get modified so they will.
 
Are the seals sold as Teflon......really Teflon......or plastic.
I know the Teflon seals sold by Crane years ago were just plastic because they would split easily during installation.
 
We use the hard white "Teflon" seals at work but not very often . I usually like PRH said cut the guides for .500 or use .530 if the guide is already that and use the PC viton seals.
 
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