Dirty oil, part II

On Jul 14, 8:55 am, "Dennis Johnson" wrote:
wrote in message

ps.com...

The temp in the pan is true state of affairs in the engine.

While that might be true, I think the benefit of measuring oil temperature
as the oil enters the engine is that it enables the engine manufacturer to
provide meaningful oil temperature specifications. For my engine, TCM says
that the oil entering the engine (after passing through the oil cooler) can
be as hot as 240°F at full power and still be acceptable. TCM apparently
feels that so long as the oil entering the engine is no hotter than that,
then the engine will be fine so long as I'm using a recommended oil. For
takeoff, the oil entering the engine should be at least 100°F as it enters
the engine.

If we measured oil pan temperatures, the engine manufacturer would never
know what kind of oil cooler we had or how well the cooler was installed and
could not specify a maximum or minimum oil temperature because they wouldn't
know how efficient the oil cooler was.

Dennis

If we/ they didn't measure the temp of the oil as it left the pan the
oil manufacturer would have no idea how to formulate the correct
viscosity, additives, and anything else needed to make oil perform at
a given temp. . In a certified plane the manufacturer knows exactly
what kind and how efficient the oil cooler is. They would never honor
a warranty if they didn't. Take a Piper, leave on the winterazation
[sp] plate that blocks alot of the air feeding the cooler. Fly said
plane through death valley when the air temp is 120+f, now take plane
to local dealer for a warranty claim for a "cooked" motor and see how
fast they laugh you right out of the hangar........ G

Ben

On Jul 13, 7:39 am, "Dan Luke" wrote:
"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?


Did you get any compression numbers from the shop? I've found that
what TCM considers to be "OK" compressions, wouldn't necessarily be
considered OK by a lot of mechanics. A friend had a cylinder in the
50s a couple of years after a TCM factory overhaul and they considered
it "OK".

John Galban=====N4BQ (PA28-180)

"John Galban" wrote:


Borescopes and compressions were ok, but I still think it was something
like
this that was going undetected. But what?


Did you get any compression numbers from the shop? I've found that
what TCM considers to be "OK" compressions, wouldn't necessarily be
considered OK by a lot of mechanics. A friend had a cylinder in the
50s a couple of years after a TCM factory overhaul and they considered
it "OK".


Compressions were all in the 74-78 range, about the same as at annual a few
months before.

--
Dan
T-182T at BFM