Those check balls and springs are in there to keep the oil pressure up at

low

 RPM when the rotors do not need cooling. As the RPM comes up the

centrifugal

 force on the balls  moves the balls off the seats allowing oil to squirt
into the
 rotors.
 In the mean time the oil pump is running at a higher RPM so the oil

pressure

 is now high enough to supply both the bearings and the oil squirters.

 Paul Lamar

Ahhhh, ok, that makes sense.  Since the time we spend in idle in an aircraft
is not insignificant, I suppose that it is best to keep the check balls in
place.

Dave Leonard

 
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