[Vwdiesel] Timing 101 question please

[LBaird119 at aol.com]

1.  Is it possible for a motor to run 500-1000 miles
with valve contact, assuming hydraulic valves are
lessening the impact on valve stem and cam?

  If it was just tapping the piston then I'd say it likely could.

> 
> Or, could the valves have been hitting all along,
> there were 2 head gaskets on this motor, to allow for
> additional clearance?  thanks Overland, your the best.
> 


  Makes me wonder if the valve stem length was ever ground down 
to the correct length (protrusion length).  :(

> 
> 2.  If the timing was advanced above spec, would the
> intake or exhaust valves make contact with pistons?
> 


  Nope, simply rotating the pump only changes the instatnt the fuel 
goes in.  That won't make a change in when the piston is up and the 
valves are down.

> 
> 3.  Does rotating the pump to set timing stroke not
> only controls the point at which fuel is injected into
> TDC piston stroke but machanically moves cam as well?
> 

  Sometimes the cam will fudge a little but it really doesn't move it
as all you do is rotate the pump around it's shaft.  The cogged belt 
should stay still, keeping the relationship of the cam, pump and crank 
all the same.  
  Just because the cam bolt was tight doesn't mean the belt couldn't have 
jumped a tooth or was set wrong to start with.  : O
     Loren