<VV> Viton O ring life

[jvhroberts at aol.com]

 Viton is a fluoropolymer, and those tend to be quite stable over the long haul. Now, 900F is more than any fluoropolymer can take, but at Corvair temps, they should never fail due to temperature. Never being half a decade or more! The other issue is chemical attack. Viton can be swollen by things such as ketones and some other organic compounds, and this, over time will cause the Orings to flake apart. No material degradation, this is a purely physical chemistry phenomenon. Fluoropolymers have poor chain to chain bonding, and if you swell them, it'll cause the molecular chains to separate, and not really get back together very well since those fluorine-carbon bonds aren't strongly attracted to their neighbors, like in ordinary rubber. 

 

John Roberts
 

 

-----Original Message-----
From: BobHelt <BobHelt at aol.com>
To: corvairs <corvairs at pacifier.com>; djrcorvair <djrcorvair at msn.com>
Cc: virtualvairs <virtualvairs at corvair.org>
Sent: Thu, Aug 4, 2011 4:25 pm
Subject: Re: <VV> Viton O ring life


Dan,
Vitons are organic matter and their life is subject to the temperatures and 
 time that they are subject to. The longer the time that they see a really 
high  temperature the shorter will be their life. It's just that Vitons will 
tolerate  a higher temperature than the o-rings that Chevrolet used. Keep 
them at room  temps and they will loast 'forever". Let them see 900 deg F and 
they will be  soon gone.
Regards,
Bob Helt
 
 
In a message dated 8/4/2011 10:53:09 A.M. US Mountain Standard Time,  
corvairs at pacifier.com writes:

I put  new Viton O rings in my Corvair about 25 years ago.  Major  reduction
> of oil leaks.  Over the years I replaced a few other  gaskets and seals.
> Now I have a new fairly big leak.  I get oil  smoke coming out the top
> grill.  How long do Vitons  last?   The shelf life is "Forever".
>
> Dan
> 65  Monza 110 Auto convertible  since  '83

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