Re: REFLECTOR: oil temp

[aegerter@dataway.ch (Simon Aegerter)]

>I have a problem of not being able to get the oil temp up to minimum for
>take off without overheating the cylinderheads  I have an engine heater on
>the engine all the time during cold weather which keeps the engine oil over
>100 degrees, but as soon as I start the engine, the cold oil from the
>coolers prevents me from getting to min. oil temp prior to cylinder over
>temp.  I read my oil temp on the line out to the coolers.

While you THINK the oil temperature is below minimum, you may actually
overheat your oil! While the oil in the cooling loop is cold, all the oil,
or almost, goes through the bypass valve. If you measure at the beginning
of the cooling loop, you don't know what goes into the engine.

What people see if they measure the oil into the engine (the mixture of
direct bypass flow and cooled oil) is this: In the beginning, while the
"plug" of cold oil holds, the oil temperature climbs and may approach red
line. When the plug finally gives way the oil temperature plunges. The
first time that happened to me, I almost went for an emergency landing!

With a parallel oil cooler in the wing root the problem isn't serious; the
plug softens when the engine compartments gets warm. With only a nose
cooler or a in-line arrangement, I don't know how this would be handled on
a real cold day. Hopefully oil pan cooling would suffice.

Best
Simon

Simon Aegerter, Winterthur, Switzerland