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.
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.
Hum-m. I was
under the impression that the limiting factor side seal
O-rings.
I’ve had the oil
temp (after cooler) up to 220 -225 a few times for very short periods on the
ground. With no effective air flow through the cooler, the before-cooler
temp was only 3-4 degrees higher. It’s a different issue when running at
high power where before-cooler temps may be 30-50 degrees
higher.
Al
That is my
impression as well. Auto racing is another matter. They are
stressing the rotor bearings a lot more than we are (mainly due to RPM) so
that is probably the weak link in their use.
Your numbers
for pre/post oil cooler temps are what I am seeing when in-flight, I.e. 180
after the cooler = 220 - 230 in the pan. This is a valuable number
with which to judge oil cooler effectiveness. If you don't get
this much delta or more, your cooler is too small or airflow too
little.
Tracy (still
can't figure out why I can't change text color after Al's
stuff)