At 11:37 AM 6/19/2001, pensioner wrote:
>Odd.  I always thought the valve was closed at below 20PSI, routing the oil
>away from the filter at low pressures, rather than the reverse of bypassing
>the filter at high pressures/volumes.
>
>pensioner (one more day pumping air and getting more confused)

Hmm.  Lessee.  There are three valves I know of, two in the filter and one
in the motor.  The one in the motor limits maximum system pressure -- it
only operates when the oil is cold.  Some folks seem to have the idea that
setting that one higher will improve hot pressure, but they're doomed to
disappointment, unless it's defective.   In the filter, one bypasses the
filter element when it gets clogged (and thus causes too much pressure
drop) and the other is a check valve that keeps oil from draining back down
out of the galleries when the motor stops.  This last one is the one that's
missing from most non-OEM filters, which leads to lifter noise on starting.

d

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"