<VV> Oil

[Steve Gangi]

 Static seals such as O-rings and flat gaskets do not wear, they shrink or swell depending on the material they are made from, the fluid they are exposed to, and the temperature. Most modern rubber materials made for automotive use are tested in a variety of oils and fuels. There is no single answer but if you have good quality Viton-style O-rings and brand-name oil I would not be concerned. Chuck is correct that Viton-style rubber is not optimum for rotating or dynamic sealing applications such as crankshaft seals. There are modern materials however that are excellent for these applications. It is often difficult to determine what material an aftermarket seal for a 50+ year old engine is made of unless you are sure of the manufacturer. When a new seal is installed, it gets conditioned to the fluid it is exposed to, swells, and takes a set. If you switch oils to one that swells the seal less, it is slightly possible for the seal to shrink slightly and leak. 

Steve Gangi
"The Rubber Guy"



Message: 7
Date: Wed, 25 Oct 2017 14:25:19 -0400
From: "BBRT" <chsadek at comcast.net>
To: <virtualvairs at corvair.org>
Subject: Re: <VV> Oil
Message-ID: <008001d34dbe$9dbd7300$d9385900$@net>
Content-Type: text/plain;	charset="UTF-8"

I get a LOT of trade publications in the automotive field. Never heard that synthetic oil wears seals, rubber or otherwise.
Ethanol affects seals.. Reported numerous times plus other ill effects. VITON seals are great for static seals like o-rings on push rod tubes. Not so good for rotating surfaces. 
Chuck S

-----Original Message-----
From: VirtualVairs 
Sounds like an old wive's tale to me. Can you forward a link to the offending article?

----- Original Message -----
From: "Richard" 

I just read in one of those ASK THE EXPERTS columns that synthetic oil can ultimately wear away rubber seals in the engine.  I know synthetic is better for hotter running engines....I was about to put it in my 66 Monza but now I don't know.     Richard Simoff