<VV> Lifter Question

[Sethracer at aol.com]

_bgilbert at gilberts-bc.ca_ (mailto:bgilbert at gilberts-bc.ca)   writes:

1) Why  do we differ from what the manual recommends?

2) If by any chance we  still had original lifters should we be using the
recommendations in the  manual?
 
As I remember, the manual said one full turn? I can think of two  reasons 
to use "less" than a full turn. First, for performance driving  at near the 
limiting RPM of valve float, there is a tendency for the lifter to  pump-up 
and fill in the gap, if the valve spring momentarily fails to return the  
valve to the closed position, the lifter adjusts the plunger to close the gap,  
then the valve is held open during the combustion cycle - never a good 
thing.  The engine will miss-fire until the pressure bleeds the oil down in the 
lifter  and the valve returns to the seat. Second, If using really old 
lifters,  there may be a "sweet-spot" range of adjustment, based on deposits in 
the  internal bore of the lifter. If turning the adjustment to a full turn 
causes the  internal plunger to catch or get stuck, you might now have a 
non-self-adjusting  lifter (equals tick, tick). Those are just two.
 
- Seth Emerson