<VV> Valve stem seals

[Rad Davis]

I don't use stem seals on Corvairs either.  The valve stems are below the 
heads, and are up at the top of the rocker box where little oil gets 
anyway.  I'm certain that I'd never use exhaust stem seals - exhaust guides 
need all the lubrication and cooling help they can get, there's no 
catalytic converter to poison, and the exhaust system is under mostly 
positive pressure anyway.

Intake stem seals make a little more sense.  As far as I can tell, they 
mostly exist to prevent the blue puff on startup when the vehicle is not 
parked on level ground.  I have seen carbon caking on intake valves from 
upright engines, but have not seen it on a Corvair.

If I went back into an engine 5 or 10 thousand miles after a rebuild, I'd 
probably put intake seals on it if I had any around.  Otherwise, it would 
be used until end-of-life teardown with no valve stem seals at all,  as all 
my other freshened and rebuilt engines have been.


At 01:54 AM 2/11/2006 -0800, Tony Underwood wrote:


>I know not what course others may take, but as for me, I don't use any 
>valve stem seals at all.
>
>The logic is that if the guides are in any shape at all, they're not 
>likely to pass that much oil in the first place.   The exhausts need all 
>the oil they can get, and the intakes which do have vacuum on them still 
>will have a hard time sucking much oil into the cylinder if the guide is 
>any good.
>
>And the guide gets kept good by having some oil on it.   It's worked for 
>me for a long time.
>
>Corvair engines simply don't suck up that much oil through the valve 
>guides unless they're worn out.   And if they are, new seals won't fix 
>much of anything.    Teflon seals can, in some cases, seal too well and 
>starve guides of oil and accelerate wear...  in some cases.    I've used 
>teflon seals before on other engines, had no problems.   I've also used no 
>seals at all on Vair engines, had no problems.
>
>Those of you who disagree, keep your pants on.  This is just the way I do 
>it and I'm a jackleg.   Don't assume I'm any authority.
>
>
>
>tony..
>
>_______________________________________________
>This message was sent by the VirtualVairs mailing list, all copyrights are 
>the property
>of the writer, please attribute properly. For help, mailto:vv-help at corvair.org
>This list sponsored by the Corvair Society of America, http://www.corvair.org/
>Post messages to: VirtualVairs at corvair.org
>Change your options: 
>http://www.vv.corvair.org/mailman/options/virtualvairs 
>_______________________________________________

__________________________________________________________________________
Rad Davis:                                        rad.davis at comcast.net
Corvairs--65, 66 Corsa coupes, '65 'brier Deluxe   http://www.corvair.org/
Keeper of the Forward Control Corvair Primer: 
http://www.mindspring.com/~corvair/fc1.html
"We did Nebraska in seven minutes today. I think that's probably the best 
way to do Nebraska."                            --Brian Shul, _Sled Driver_