Racing Beat recommends maximum oil temp into the engine
210 degrees.  What determines this temperature, the oil
scraper rings?  Something in the engine itself?  (I don't have
the book in front of me).  Would Mobil One allow you to
run higher oil temps (even though you may not want to)?

--
Perry Mick
Duckt N7XR
http://www.ductedfan.com

Good question.

That could be any one of a number of things. It could be the stock
oil-control rubber O-rings or it could be just to
cool the rotor and main bearing material. On the other hand the apex
seal runs up there around 500 degrees F so it could be to enhance
the heat transfer between apex seal/rotor and oil. Next time
I am talking to Jim Mederer I will ask him this question. Also
once we get some experience with the teflon seals and high oil temp
perhaps we will find out what the real number can be. Chuck Is building
an engine with the teflon oil control O-rings. In theory these should
be good to 500 degrees.

BTW the guy said 7000 mile oil-change for Mobil One in a car.

Paul Lamar

I don't know why Racing Beat recommends that particular temperature, but in the Deere / RPI engines, we had a similar limit based on viscosity and oil film thickness in the main and rotor bearings. It could also be that exceeding 210 in will cause the sump temperature to get too high with resulting rapid oil degradation. Oil degradation takes off with a "knee" in the curve at about 250F. Mobil 1 probably does not have very different high temperature viscosity characteristics than conventional oils. Mobil 1's viscosity has been tailored more for easy cold starting and cold temperature bearing protection. The other properties are certainly much better at high temperature -- things like oxidative stability, etc.

I doubt that apex seal lubrication has anything to do with it. The film is so thin, it is going to respond to the metal and gas temps really quickly, without much influence from the build temp at which the seal lube was introduced.

Jon

I have been using Mobile One 15-50 in the cars and the guy said a possible
reason for my oil pressure to take 30 seconds or so to come up ironically is; 
the oil is too viscous at 65 degrees F! He suggested the 5-40. I think perhaps it is 
where Ford located the oil pump in the modular V8. On the cranks nose, up out
of the oil level. As you might note the Chevy small block V8 had the
oil pump down in the pan submerged in oil all of the time.

When Andy Venable lost oil pressure in his plugs up engine I think
the higher position of the worn pump had something to do with it.

When seeing one G or more in a racing car turn the stock Mazda rotary 
oil pump is going to have a harder time of it as the pickup tube goes
off at a lateral angle. A dry sump system would work better IMHO.

I digress.

Paul Lamar
 
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