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On a recent trip from Florida to Tennessee I
observed oil temps in the 150s.
My engine is an IO-550N built by Monty
Barrett. I decided not to install a remotely controlled oil door because I
had been told that low oil temps were rarely/never a problem in the
Legacy. My experience differs.
When I started the flight OATs (8000) ft were
in the 40s and oil temps were in the 180s. But by the time I finished OATs
(8000) were in the 20s and oil temps were in the 150s. Related to and
probably partially the cause of the problem was my use of a low power setting
(2300 RPM, no ram air, 30deg LOP) to extend range. Correct, running lean of
peak will reduce oil temps which is a good thing....to a
point.
Can low oil temps shorten TBO/damage the
engine? I
don't think 150 degF will shorten TBO.
Even with regular 25 hour oil changes
using Exxon Elite? see above.
Should I go to the trouble to retrofit a
remote oil door, If oil
temp stays or goes much below 150 degF in cruise, I would install an oil
door. or just change my oil at a shorter interval? This will not help at
all. The cool oil will last longer than hot oil. I think everyone
will say 180 degF is a "good" temp. 160 is OK as well.....as you go below
150 the grey line develops. All of this is my opinion. When I
road raced cars we tried to get oil temp to 150degF before the race
started. I would not suggest anyone cruise an airplane at 120 degF oil
temp for example and I don't like oil temps above 200 degF. Also, I would
prefer oil temp at 150 degF vs 220 degF for
example.
Enquiring minds wish to know.
D. Brunner
Craig Berland
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