I only use the exhaust port gaskets that are metal on one side, and fiber on
the other side, on waterboxer engines.
I'd say they last super fine ..
how flat the flange is that's bolted to them is a factor.
they warp a bit.
sometimes you can surface them a bit with a file  very carefully.

I get more than two or three years out of them I'd say.

----- Original Message -----
From: "william greenamyer" <wgreenamyer@CISO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, September 23, 2010 7:08 PM
Subject: Vanagon exhaust gaskets for 84GL Vanagon

>I have another question someone might be able to answer.  Since I have to
> pull apart the exhaust system again to fix some gasket leaks, I was
> wondering why the exhaust gaskets to the heads (metal one side and fiber
> on
> the other) are not designed like the catalytic converter and muffler
> gaskets
> (several layers of thin metal)?  I have also seen solid metal gaskets (or
> I
> am guessing they are gaskets) but don't know what vehicle uses them.  I
> have
> tried all fiber gaskets (in the early days) and they just blew out on the
> Vanagon.  Was told I needed the metal on one side and fiber on the other
> side.  They lasted a little over 3 years and two are bad now.
>
> William