Multiple studies show excess cylinder wear occurs at temps under 160*. Engineers generally recommend 160* or more to prevent cylinder wear. There is virtually no differance between 160* and 180*.
And, really, I don't expect to get 120,000 miles out of this engine.
Oil temp is another issue, though. It's generally accepted that minimum operating temp is about 180*+. RP says there is no minimum on their
oil m- although I'm not sure I believe that. I can get my temps up to 180-190* on a cold day, but I have to work at it. That's why I use a seperate electric
oil pump for the cooler.