The oil does stay clean between oil changes. I change around 40 hours. I
have about 200 hours on this factory overhauled O-360 engine. I have to
run 100LL in it. I add a quart about every 13 hours. I am going to play
with a winterization plate this winter. I believe the Piper Arrow that
has the same engine configuration has a winterization plate that has
about a inch and a quarter diameter hole in the middle. That seems too
small though.

Ross

" wrote:

Ross

I have a 172M with an O320E2D @1700 hrs TTSN with the same oil filter
system that likewise is cold blooded. My guess is that ours has very
little blowby as the oil also stays clean for many hours after a
change. It has been run mostly on MoGas, so the contamination load on
the oil is low. Does your oil stay clean unusually long too?

Have you tried covering part or all of the oil cooler?

Ours does not have a Vernatherm element installed in the oil filter
adapter - only a plug. Does yours?

My guess is you have a very good break-in. I don't think it is
something to worry about.

The justification for having the oil run above 180 degF though, is
that the dew point of the combustion products is about 180 degF.