spaco fired this volley in
:

You say "pumping oil", as opposed to "putting oil under pressure".
It would make a big difference it you comment on the pressure you
NEED and the flow in gpm that you want. Also, is the oil clean or
not?
I don't think power steering pumps like dirty oil. Are you
"building

No gear pump likes dirty oil, but if this is a zero-pressure use, then
gear or rotor wear won't significantly affect the volume the pump can
move.

High pressure-Low bypass pump performance is predicated on precision
fits, which will go away quickly in the presence of dirt. But low bypass
is not necessary except at pressure. You could still move a lot of oil
with several thousanths of excess clearance in the elements.

LLoyd