

| Subject: | Max Oil Temps. - a reference! |
| From: | Dave Kautz |
| Date: | Fri, 9 Feb 96 10:27:35 PST |
During the 15 months or so that I've been following vanagon@lenti the question of what is a maximum safe oil temp has come several times, with anecdotal and speculative suggestions as to what it might be. I've been reading a book a a co-worker loaned me called "The Sports Car - It's Design and Performance" by Colin Campbell. There are several pages devoted to the discussion of lubrication from which a couple of remarks may be of interest: Bearing failure is "anticpated" when oil temperature at the bearing reaches 340 degrees F. However, the oil temperature at the bearing is higher than what is measured in the distribution gallery by as much as 85 degrees F.! Subtracting 85 from 340 gives us a maximum gallery temp. of 255 degrees F. HOLY SHIT!!, you say, I've taken my engine higher than that! But there's a catch for most of us, we don't know what the oil temp in the gallery is - most folks have mounted their temp sensors in the sump and are measuring the temperature of the oil BEFORE it has gone through the cooler. Does anyone know what the temperature drop is across the cooler? Eugene Palmer had a setup on his full-tilt-boogie engine which had a sensor IN a cooler, I think. Are you out there somewhere, Eugene?? One other caveat. This book was published in 1978, oils supposedly have gotten a bit better since then in their resistance to temperature. Perhaps we have picked up some margin. I'll repeat what the Pennzoil technical rep. said for those of you who haven't heard it before: 230F is the "correct" oil temp and oil should be changed if it has taken excursions in excess of 300F. Still gaugeless - "ignorance is bliss", Dave
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