[Vwdiesel] Head gaskets

[LBaird119 at aol.com]

In a message dated 6/21/2006 10:17:32 PM Pacific Standard Time, 
hwy9fergs at comcast.net writes:

> When much more is taken off, wouldn't the valves and valve recesses be 
> moved closer to the pistons than they were originally designed to be?  Why does 
> the book state absolutely no shaving of the head is to be done (although we 
> seem to get away with it)  I just don't know what sort of insidious problems 
> might occur from going away from the original specs. Think in terms of keeping 
> the valves the same distance away from the pistons and 
> I'd say you're safer.  Doug 
> 

  Somewhere it says it's due to the two different materials; the head 
and the inserts.
  Thing is...  If you surface the head let's say .010 (really warped) about 
.007 of that is going to come off of the perimeter so that's about a thou 
or maybe two coming off of the outside two valve areas and next to nothing 
from the center two.  Rework the head and you'll grind the seats and valves.
The valves will be recessed much more than you're removing so in reality 
you're LOWERING the compression when you rework a head and surface it.
Don't grind the valves and you can bet they've settled that couple 
thousandths from the time the head was new or last reworked.  You'll 
end up net or still lower.
  I had one surfaced to where he hit valves.  Didn't charge me because of 
it.  Worked fine, sounded great, no piston to valve interference.  Don't 
remember specificially checking compression but there were none of 
the symptoms of high compression (yes, there are symptoms.)
     Loren