A lot to think about! I appreciate the good advice.
There is a problem I am trying to resolve, or maybe I am making too much of the engine temperatures? With no thermostats, when I start the engine in autumn, not even winter:
1) I can idle for 10 minutes and the oil temps won’t even move up to 120 while the oil pressure remains around 75 psi. Coolant does begin to come up to 120 during that warmup time. Then, with these readings, I take off. Is that ok?
2) During flight, the oil and coolant temps might reach 170. During the dead of winter, I expect they are likely to be lower. Is this ok?
My grass strip does not have electric power. And I don’t really want to go through an elaborate pre-flight heating of the engine with external heaters every time I fly. Am I wrong to not do this?
My questions are obvious.
1) Aren’t these low temps both during takeoff and during flight going to have an accumulative negative effect? Or should I just change the oil more often?
2) For that matter, during extreme cold, does even starting without heating the engine damage it?
3) Will I be able to tape over the cooler and radiator enough during winter to keep temperatures high enough during flight, and not overheat during normal air temperature fluctuations? Based on the reliability discussion, I am leaning this way.
Thinking about what you say, I might permanently remove all the thermostats after winter, and leave them off. You’ve all made a very good point about this being an airplane, and what if either thermostat (oil or coolant) fails in a way that bypasses the cooler/radiatior and heat gets out of control, especially with no airport nearby. But I still like the idea of an oil to water heat exchanger in addition to, not in replacement of, the oil cooler, strictly to heat the oil more quickly during warmup, which does not occur during idle even with a thermostat.
Having already said I lean toward removal of both thermostats, I still want to discuss them. With the Thermo-Bob, coolant temperatures come up nicely to 180 in a 10 minute warmup. It would be really nice to bring the oil temps up as well. The PermaCool does raise inflight temperatures, and seems to do a great job with the new Stant 195 degree in lieu of the factory 170 waxstat, but does not seem to raise oil temps during warmup (too much oil mass, not enough heat, at idle).
And, oh by the way, I contacted PermaCool to find out which manufacturer waxstat they are using, but they refused to tell me. So I replaced the 170 with a 195 (a Stant I mentioned earlier – but I plan on replacing that Stant with what follows). I looked at all the engineering drawings I could find online and found it is most likely a MotoRad. The 195 degree MotoRad P7200-195 has identical dimensions right down to the casting marks on the bottom of the waxstat. And, in support of the loss of reliability argument, I put the 170 (just removed) and MotoRad 195 in boiling water. The 170 failed! It would not expand at all. But the new 195 worked fine. But this makes me wonder what would happen in flight if the Permacool were letting this much oil bypass the cooler all the time. When did the 170 fail and why did I not notice that inflight. Temps inflight with the 170 had been very low, as expected.
I still am thinking about reliability overall, while keeping operating temps in mind.
Thanks,
Dennis
