I've noticed a strange problem lately though.  I've only
recently started continuous operations above 5000 RPM,
so it could have been there before but didn't notice.

Climbing out if I leave it at full throttle (something I never
used to do after the first 1000 feet) the oil pressure slowly
drops from 80 to 40 psi.  If I level off and remain above
5000 rpm the pressure stays low.  But if I back off the
throttle to around 4800 the pressure suddenly goes back
to normal 80 or so within 5 seconds. Oil temp remains
stable at 200 throughout.

In cruise if I then increase the throttle above 5000 rpm,
the pressure will slowly drop down to 40 again, over
a period of a few minutes.  Reduce the throttle, pressure
recovers to 80 in a few seconds.  Any ideas?

I called John at Mazdatrix, he thought maybe a bad
sender, which is easy to check.  I'll replace it tomorrow
morning and try it.  He also thought maybe the front pressure
relief valve (I don't have the Mazda books here in front
of me so don't know if that's the right name) may be
leaking, and mentioned putting some spacer washers
in it.

I'd like to find the problem and fix it, but haven't been
overly concerned since Tracy flew to OSH and back
with 37 PSI oil pressure.  Can you rotary experts out
there give me a clue?
--
Perry Mick
Duckt N7XR
http://www.ductedfan.com

The guys at Mazdatrix probably covered this already but if nothing else
turns up, consider the possibility that oil foaming could be the cause of
the pressure drop.  Usually it occures around 4500 rpm and only about a 10 -
20 psi drop but every situation can be different.  I use an anti foaming
tray in the oil pan (part of my engine mount )and it eliminated the pressure
drop completely.  I'd check out the other possibilities first though.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

Perry uses one too Tracy. Here is a picture of Perry's.
Do you have a picture of yours?

Paul Lamar
 
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