Re: Oil Temps

[Robert Houk - SMCC Bos Desktop Hardware <rdh@UrQ.East.Sun.COM>]

   Glen Powell wrote something to the effect of...

   You want you oil to be at the minimum above boiling of water to rid the system
   of moisture...

   A few points here:  If the moisture were to be "gotten rid of", where would it
   go?  Aren't the oil systems closed.  Suppose then it stays in the system as
   steam.  Steam is worse than water for corrosion, aggressive tendencies, etc.
   And a final point:  The boiling point of water is 212 F or 100 C at standard
   pressure  (1 bar).  My engine oil (system) is only at 1 bar when the motor is
   off.

No, your "sump" (assuming not a dry-sump system...) is a atmospheric, more
or less. Only the oil galleries are under pressure.

The "crankcase" is in turn vented back into the intake manifold so all those
noxious blowby products are burned up, and not just vented into the atmo-
sphere.

Any moisture in the oil is vaporized in the crankcase, wherein it works its
way out of the engine via direct venting (obsolete) or venting back into
the intake system.

We're not talking lotsa water here, only tiny amounts from piston blowby
that condense onto a cold engine wall surfaces and drip into the oil. But
enough of it over time accumulates "acid" which does damage the engine.

   I look at the temperature of oil in a performance oriented fashion:  I want it
   warm enough so that it flows, but not so warm that it breaks down quickly or
   loses its lubrication properties.  I also keep an eye on the oil pressure.  If
   it tops out at 5 bar under acceleration, stays somewhere between 3 and 4.5 ish
   when driving and stays above 2 ish when idling (after warm up) then I feel the
   viscosity is about right.

   I have seen the temp move above the 130 C tick on my car, but that was during a
   driving course:  lots of revs, little airflow.  On the Autobahn, even after 130
   mph for two hours or so (it was late on a Sunday -- roads were clear) the oil
   temp wasn't very high -- maybe 110 ish.  Normally around 100 plus/minus.
   (around/above the tick between 60 and 130.

Even at a mere 60C, the water will eventually evaporate out . . . but not as
fast as at 100+C;

					-RDH