oil temp answer

Your results are right in line with an article I wrote a few years ago. In it, there were results from an oil company's tests where they mounted sensors inside the block to measure temps at the bearings. Those oil temps averaged some 40 degrees hotter in the bearings than in the pan. This's what makes me say that if anyone's pan temps are approaching 280F, you need an oil cooler since the in-bearing temps are likely approaching 340F! And this is dangerously close to the charring temp of normal oils. Synthetics give an extra 25 degrees of protection, but no engine should be expected to run very long under heavy load with oil temps at or near this point. Thanks for the data.

I have been wondering about this as well; I think that the oil temp sending sensor location is a key factor in the question, when you consider the NASCAR guys saying that the oil temp is 240 degrees and the water temp is 230 degrees and the engine is spinning at 9000 RPM they are happy I suggest that the sensor for the oil temp is located on the oil/water exchanger and not in the oil pan or the engine block.

Snip.....
when you consider the NASCAR guys saying that the oil temp is 240 degrees and the water temp is 230 degrees and the engine is spinning at 9000 RPM they are happy

Don't draw too many conclusions from NASCAR engines since they all run 18-22 quart capacity dry-sump oiling systems, water-to-oil heat exchangers and 25-28 psi radiator caps with as big an aluminum radsiator as will fit, and no fans whatsoever. But checking oil temps at two or more places will provide a guideline if your car runs hot oil temps. Just remember, all our data is for pan temps so you'll have to sort of delevlop your own limits with the 'other' points.