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Message
Mine is taken in the oil pan, where it is the highest temperature.
I
have seen 260 F. many times, and I consider that normal during climb
and
taxi. I also use Mobil One Synthetic oil, to tolerate the heat.
During
cruise it will stabilize at 220F.
You need to get the oil above
220 F, to evaporate the moisture anyway.
Hi George,
The
"standard" (closest we have to one) for measuring oil temp is to measure it as
it returns to the engine, after the cooler. According to Racing Beat, this
temp should never exceed 210 F. Lot's of folks have exceeded this for
short periods, up to 240 F or so, and have had no problems, but it's not
something you really want to keep doing.
As I
understand it, the issue is not the breakdown of the oil, but the melting
of the rotor bearings. I've never seen this myself, but it makes
sense to me. After all, since we use oil to cool the
rotors, it's easy to see that they will overheat as the result of
overheating the oil. The oil flow through the bearings also takes
away lots of heat, so the rotor bearings become the first thing to
go.
The biggest
problem with measuring the oil in the pan is that it may not be the most
consistent measurement. Oil drains back from several locations, sloshes
around, etc, and you only see what's at the sensor. Still, it's probably
OK to measure there, but there's no accepted spec for allowable
temp. I'm sure your 220 F cruise is below 210 F going into the
engine, but I'd bet that 260 F in the pan is pushing
it.
As for
desired temp, I believe Lynn has mentioned that 180 F (after the cooler) is best
power for oil, and that you lose power above that temp.
Cheers,
Rusty (two
more weeks)
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