My experience at Cummins showed that the oxidation rate of conventional motor
oils really takes off right about at 250F. I would not recommend steady state
operation at that sump temperature. Also, the viscosity of the oil will be
reduced with higher temperatures. In the RPI / Deere rotary engines, bearing
oil film thicknesses got to be critical with oil temperatures below 250F. The
Mazda bearings might be a bit better, but I wouldn't count on it. Your call
if the trade off for a smaller cooler is worth the risks.

Jon Lauter
Rotary Power Marine Corporation
www.rotarymarine.com

I assumed one uses synthetic oil. I have never really got a definitive 
answer on why Mazda seems dead set against synthetics. Perhaps it is the wetting
properties compared to conventional oil. Also as a recall synthetic oil seems to 
run off surfaces after sitting for awhile. Tracy is running synthetics as
I recall.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

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