The reason VW says not to grind exhaust valves, is due to a surface
hardening process that is ruined by grinding.  Intake valves don't have this
same treatment, and as such are OK to re-grind.
  Any good VW rebuilder knows this, and heeds the factory's advice to
prevent exhaust valve failures (ie; shortened life).  They do a good enough
job failing on thier own without this added assistance.......

Mike B.

----- Original Message -----
From: "Evan Mac Donald" <macdonald1987@SBCGLOBAL.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, July 06, 2007 11:41 AM
Subject: Re: exhaust valve grinding

> As long as the minimum thickness at the edge of the valve is not violated,
> nothing bad. My brother did the machine work on the heads of my 1.9l about
> 140k miles ago. Nothing bad has come of grinding the exhausts. Now, he did
> take minimal cuts on all the valves - just enough to get a straight seat.
> We did that on the valves and on the heads. It amounted to just a little
> more than a "hard" lapping, IIRC. Not alot needed to be done. I was glad
> for that, because exhaust valves are the very devil to lap by hand,
> because they are such a hard metal. BTDT!
>
> "Giasson, Pascal (DNR/MRN)" <Pascal.Giasson@GNB.CA> wrote:  I just got a
> valve job done on my 1.9 heads from a machine shop. I gave
> them the Bentley and showed them where it says not to grind the exhaust
> valves. They said they have reground exhaust valves many times for the
> local VW mechanic and this was the first time they were made aware that
> VW says not to grind them. I thought they were just going to lap them
> as per the Bentley, but the machinist said they needed to be ground so
> that is what he did. Does anyone know what will happen to a ground
> exhaust valve? Thanks
>
>
>
> Pascal
>
> '84 Westy
>