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Valve Seal - too tight, broke on install
Posted by: wittsend ()
Date: July 27, 2020 05:16PM

I have a set of Teflon valve seals. They seemed a lot stiffer than other seals I've used. I found an appropriate sized socket, lubricated the guide and tapped the seal into place. That was tight but OK.

When I went to install the valve I checked that the stem was aligned over the hole. The valve met significant resistance. I lightly tapped the valve face with a plastic hammer but the seal was SO tight to the stem that it popped the seal off the guide.

Thinking I'd reverse the order, with the valve in place I attempted to tap the seal over the valve stem but it met so much resistance the seal broke. Something about these seals just doesn't seem right. And, note this did not catch in the keeper groove. I couldn't even get the seal over the beginning of the valve stem.

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Re: Valve Seal - too tight, broke on install
Posted by: jasvair ()
Date: July 27, 2020 05:22PM

The teflon ones are hard to put on. I sell the viton valve stem seals and they are the best. $11 per set plus shipping.
John Sweet
John's Corvair parts

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Re: Valve Seal - too tight, broke on install
Posted by: wittsend ()
Date: July 27, 2020 05:39PM

I did some checking. The factory specs on the valve stem are .3415-.3422. My stem measures .3417. In spec and to the smaller side.

I don't have a tool to measure the seal so I used a drills to get a rough size on the seals internal diameter. A 5/16" (.3125) drill slides onto the seal with the tension normally found when placing a stem to a guide but that tension would put the actual seal hole below .3125. That means the stiff, Teflon seal is at least .030 smaller than the the valve stem. That just doesn't sound right?

Bummer this is the FIRST part I'm installing to put my engine together..., and this happens.



Edited 1 time(s). Last edit at 07/27/2020 05:43PM by wittsend.

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Re: Valve Seal - too tight, broke on install
Posted by: Frank DuVal ()
Date: July 27, 2020 06:05PM

I put the valves in, then slide the seal over the valve stem. Clark's used to supply a little plastic sleeve to help slide the selas over the vale stem/keeper grooves. But it was still hard. Never used a socket, but my hands were stronger then! Do lubricate the stem with water, oil, ATF, something....

And make sure there is a slight chamfer on the stem end. Just slight. Sometimes used valves have a sharp edge with a slight mushroom.

Frank DuVal

Fredericksburg, VA

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Re: Valve Seal - too tight, broke on install
Posted by: wittsend ()
Date: July 27, 2020 06:48PM

I tried that method the second time and the plastic sleeve just got destroyed as the seal went over the keeper retainer groove.They are that tight. And, yes, lube and the chamfer on the valve was there. I'm done with these Teflon seals. I'll "eat" what I paid for them and get the Viton's. This car is never going to see more than 1,000-2,000 miles in my lifetime.



Edited 2 time(s). Last edit at 07/27/2020 06:49PM by wittsend.

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Re: Valve Seal - too tight, broke on install
Posted by: Wagon Master ()
Date: July 27, 2020 07:04PM

Doesn't matter to me what seal material you go with, .030 interference fit can't be right.

'29 Ford Model A Tudor
'61 700 Lakewood 110 4 speed
'69 Monza Convert. 140 Auto.
'70 Dodge Challenger R/T 440 4 speed

Been aircooled since 1973
Northwest Ohio

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Re: Valve Seal - too tight, broke on install
Posted by: joelsplace ()
Date: July 27, 2020 07:37PM

I don't know what size the seals should be but Teflon tends to be really stiff. In other applications I soak it in hot water for a few minutes before I try to stretch it.

Joel
Northlake, TX
5 Ultravans, 113 Corvairs and counting...

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Re: Valve Seal - too tight, broke on install
Posted by: CoCoCo ()
Date: July 27, 2020 08:05PM

Not to bash any suppliers for this, but would this not justify a return for refund? I don't know if .030" is excessively tight, or if that's normal and only a professional with some kind of special tool can install them (not that I remember, but it's been a long time for me).
If normal, then there's nothing for it. But if it's out of spec it seems like they can call the manufacturer to get it taken care of.
The others will have to say that's correct or not. But if you can't install them without destroying them, that seems a bit much.

The good serendipity part of this is that you get to use the better Viton product. Never used them myself, but after the o-ring trouble I've been a big Viton fan for all these years.
Hope it makes as good a stem seal as it does a pushrod tube seal!

Paul

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Re: Valve Seal - too tight, broke on install
Posted by: The Stig ()
Date: July 27, 2020 08:15PM

I have installed those plenty and they are always a pain. Used to have a spare set for the ones that broke. I go for the more common viton anymore.

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Re: Valve Seal - too tight, broke on install
Posted by: JimBrandberg ()
Date: July 28, 2020 06:12AM

Yes they are very hard to get on so don't feel bad. I've destroyed them and been frustrated too. I've been using black rubber because I have some. Is viton a good choice? It's not so good with something that revolves against it, is something that slides against it okay? I'm not disrespecting the viton just asking. I've been using the blue viton accelerator pump cups hoping they will last longer than the black ones with the gas today.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Valve Seal - too tight, broke on install
Posted by: texas yenko dude ()
Date: July 28, 2020 06:59AM

The solid Teflon seals are horrible. They are hard and are not always round. Use the rubber with the small Teflon seal or the Viton ones like John sells. You will be much happier

Texas YENKO Dude
YS-070
YS-199
YS-320
Southeast of Disorder


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Re: Valve Seal - too tight, broke on install
Posted by: thewolfe ()
Date: July 28, 2020 07:18AM

Ditch the teflon and go with viton. They are easy to put on and will last a long time.

Nate Wolfe
Portland OR
65 Corsa 180

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Re: Valve Seal - too tight, broke on install
Posted by: wittsend ()
Date: July 28, 2020 09:33AM

Viton's purchased. Thank you all for your advice - and sympathy.

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Re: Valve Seal - too tight, broke on install
Posted by: wittsend ()
Date: July 31, 2020 07:58PM

The installation of the fast arriving Viton seals (thank you) went smoothly. The lip of the seals can be potentially damaged as the seal goes over the sharp valve stem tip and the keeper groove. I thought I had the thin plastic piece from another seal replacement but couldn't find it. Who knows it might have been too small/large anyway.

What I wound up doing was cutting about a 1" length of heat shrink tubing and shrinking it over the valve stem leaving about 1/2" above the stem so it would taper. Lots of lube and it went on smoothly. I was able to pull it off and reuse it. When I started the second head I reheated it a second time to tighten it up a bit.



Edited 1 time(s). Last edit at 07/31/2020 07:59PM by wittsend.

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Re: Valve Seal - too tight, broke on install
Posted by: JimBrandberg ()
Date: August 01, 2020 06:34AM

That's a nifty idea.
I've got a little drawer full of teflon seals and it's hard for me to just throw them away.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Valve Seal - too tight, broke on install
Posted by: 66vairman ()
Date: August 01, 2020 10:58AM

JimBrandberg Wrote:
-------------------------------------------------------
> Is viton a good choice? It's not so good with something that revolves against it, is something that slides against it okay? I'm not disrespecting the viton just asking. I've been using the blue viton accelerator pump cups hoping they will last longer than the black ones with the gas today.

Viton is a Dupont name for FKM. Many different compounds are made for different uses. It's been reported here the Clark's Viton crank seals don't last, maybe they are the wrong compound. Based on statements here the Viton valve seals do work.

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Re: Valve Seal - too tight, broke on install
Posted by: wittsend ()
Date: August 01, 2020 11:02AM

I don't know, those Teflon seals I got were SOOooo tight I think they would just tear the heat shrink. But, nothing lost in giving it a try.

They say the Teflon's last longer but this motor will see 1,000-3,000 miles before they start to hide the keys on me (or I forget what keys are). So, for me, longevity is not the need.

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Re: Valve Seal - too tight, broke on install
Posted by: joelsplace ()
Date: August 01, 2020 01:57PM

One trick on seals to protect the lips is cut the corner out of a plastic bag to put over the valve stem. The heat shrink is probably better but a plastic bag can be a lot thinner.

Joel
Northlake, TX
5 Ultravans, 113 Corvairs and counting...

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Re: Valve Seal - too tight, broke on install
Posted by: autocomman ()
Date: August 02, 2020 07:02PM

Viton FTW

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