<<Posted for "Christopher Zavatson" <Christopher.Zavatson@udlp.com>:
Gary,
To me those temps sound dangerously high.  I can't speak for all
Lycoming models , but redline on the O360A1A is 245F for oil inlet temp.
I imagine  the oil experiences a much greater temperature rise in these
air cooled engine since Lycoming doesn't worry about burning off
moisture until the oil remains below 140 or 160F(I forget the exact
number).  The vernatherm regulates to 180F for this reason.  I am
familiar with the higher temperature limits on oil for diesels (military
applications), but do not think it is a good idea to replace Lycoming
specifications with those of an entirely different type (water cooled)
engine.
Chris
N91CZ
360std>>

I certainly don't disagree with Chris here, but as I recall the original
concern was oil temps that seemed high, but still at or not much above the
245 red-line that Lycoming suggests.  On my Cessna the temp will get to the
red-line on a sustained climb at high ambients.  I haven't considered
grounding the airplane because of it.  Also, high oil temps are mostly a
factor for the life of the oil, not the engine.  I expect one could worry
about coking in the ring lands, etc. if running for sustained periods above
the red-line, but otherwise, it is a thing to work on, not a thing to be
overly concerned about.  Again, just my opinion, as I am neither an A&P nor
a lawyer.

Gary Casey
C177RG