It was Continental Motors, not aircraft, about 70 years ago

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h. I recreated the graph from an old engine textbook so it isn't perfect but it's very close. The only details I have about the test is that it was run for 60hrs and done by Continental Motors. The book is copyrighted 1986 so the test is at least 20 years old.

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http://www.robroygregg.com/Number50/CylinderWear_Temperature_z.png

another interesting chart:

https://www.offshoreonly.com/forums...igh-oil-temperature-wmoil-temp-chart.jpg

If you run high coolant temperatures perhaps you need an oil temperature gauge