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Old July 13th 07, 09:35 PM posted to rec.aviation.owning
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Default Dirty oil, part II

On Jul 13, 9:11 am, "Jim Burns" wrote:
As an aside IO540... our Aztec engines run hot. With the Piper oil temp
probe located just after the cooler and the JPI probe located ahead of the
#1 cylinder, the Piper oil temp rarely hit 200 but the JPI's will show 230
and if we climb out too steeply they'll bust the 235 alarm. I changed the
oil and filters in ours last night and noted about 1/2 dozen carbon
particles in the sump screens of each engine with a few small chunks in the
filters. 66 hours on filter changes. Oil had 33 hours on it and was brown,
definitely not black.
Jim

"Dan Luke" wrote in message

...





"Jim Burns" wrote:


From Sac Sky Ranch:
1. Blowby of combustion gases past the piston ring belt. Accompanied by
high
oil temperature and increased oil flow out engine breather. Check engine
compression.


Borescopes and compressions were ok, but I still think it was something

like
this that was going undetected. But what?


oil temperatures. (any carbon deposits in the screen or
filter?)


Oil temp. was monitored on the JPI engine analyzer with a high alarm

setting
of 215 deg. F. Never had an alarm.


3. Contamination of oil.


That's what my regular mechanic said.


--
Dan
T-182T at BFM- Hide quoted text -


- Show quoted text -


I have never understood why the manufacturer would plumb the oil temp
sender after the cooler, it gives a false reading. If the cooler was
very efficient it could shed 50+ degrees. So lets say the after cooler
temp was 220 degrees after a long climb out during hot weather, that
would mean the actual oil temp in the pan of the motor was 270+. Funny
the FAA lets the certified planes get away with it plumbed that way.