Marshall S. Smith wrote in article ...
I have always loved that line, "...I have heard...", and, as far as what it is worth, in my mind it is usually worth nothing.
Where did you hear this? From a total stranger at a party? In the next stall in the men's room? From your brother-in-law who owns a $150 Craftsman tools set and calls himself a mechanic? At the local bar?
For a guy with a *.edu e-mail addy, I would have thought you would quote some sort of authoritative source instead of using such vague language.
And, to answer that question that just popped into your head, "Yes. I taught Vocational Automotive Technology for 10 years."
First of all, most street-driven cars do not develop the sort of oil temps that are generated under racing conditions, so it would be virtually impossible to work a street engine in such a way that its oil temps are maximized.
Let's see, 25° C is equivalent to approximately 77° F
On a street-driven engine running oil temps at approximately 200° F, you would be talking oil temps of approximately 125° F with such a drop - which would be providing minimal - if not measurably inadequate - lubrication from oil which has been designed to run at a much higher temperature.
What minimal - if any - benefit you might gain in subjecting seals and gaskets to lower heat will be more than offset by engine wear - such as bearings - from oil that is not being used at optimal temperatures.
If your friend saw this sort difference in oil temperatures in his racing engine, he should be concerned, because one of two things would likely be happening.
A.) If the 77° F drop brought his oil temps back to more normal 250° F range, that would suggest that his oil temps had been running in the area of 330° F - which would indicate to me that there was some sort of mechanical problem in the engine driving the oil temps to an unsafe range. I doubt if his engine would have run long at full-song under those circumstances.
B.) If his oil temps had been operating in a reasonable 250° F range, the resulting 77° F drop would bring the oil temps down to around 175° F - a temperature range that really doesn't allow an oil to fully warm up and to function at its designed temperature range. Again, I doubt if his engine would have run long at full-song under those circumstances.
Methinks he was quoting the "company line" about one of synthetic oil's purported "benefits" due to his sponsorship.
In our experimentation with synthetics versus conventional gear oils in the transmission and rear axle of a real race car, we plumbed in pyrometers to the transmission and rear axle.
We found approximately 10° F temperature differences - not anywhere near what the synthetic sales rep had promised us......if we had only taken his word on it. (NOTE: The word "synthetic" in the previous sentence may be used as a noun and/or adjective)
Additionally, one of the "benefits" presented for the synthetic gear oil was its ability to "climb" the gears due to its stringiness - a demonstration carried out on a countertop, hand-cranked, multi-gear display comparing conventional to synthetic.
Problem is that such "clinginess" has been shown on the dynamometer to unnecessarily use up horsepower in pulling the lube around. Besides, as I pointed out to "Synthman", the top gear on the conventional oil side of the display was wet with oil. It just didn't do it in such a dramatic fashion.
I believe Lucas uses a similar countertop display to sell their snake oil. Try it next time you see one of these displays. The top gear on the "untreated" side gets lubricated.
Bob Paulin - R.A.C.E. Race Car Chassis Setup and Dial-in Services