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CHT & Oil Temp ??

R

Rolly9

Active Member
I have been flying -9 for almost 2 years. I never see CHTs above 310 in winter or 350 in summer. Oil Temp is never above 170 winter or 175 in summer. This winter (OAT 25F @ 5k) with the oil cooler completely blocked, and 2500rpm, it finally got to 185. But as soon a I reduced power to land, the temp came right down. Seems to me things ought to run hotter. If so, What to do? Thx.
Rolly C. Eatonton, Ga.
 
Rolly9 said:
I have been flying -9 for almost 2 years. I never see CHTs above 310 in winter or 350 in summer. Oil Temp is never above 170 winter or 175 in summer. This winter (OAT 25F @ 5k) with the oil cooler completely blocked, and 2500rpm, it finally got to 185. But as soon a I reduced power to land, the temp came right down. Seems to me things ought to run hotter. If so, What to do? Thx.
Rolly C. Eatonton, Ga.
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Same here. About the only thing that will get the oil temp up is to remove the cooler from the loop or block exit air. I've had mine completely blocked all winter and max oil time has been 175-180 but most days around 140. In the summer months with the cooler open and full 4" air to it, OT seldom goes to 200.

Another solution is go with a larger engine. The angle valve motors produce more power and more heat. :)
 
Rolly9 said:
I never see CHTs above 310 in winter or 350 in summer. Oil Temp is never above 170 winter or 175 in summer.
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Are you bragging or complaining?:) Those temps seem perfectly fine to me, not sure why you think they need to be changed. I'm sure I'll be soundly rebuffed by the "oil temps must go over 210 degrees on every flight" crowd, but my XP-360 manual shows the "normal operating" range down to 130. Others have posted that Lycoming says ~160 (don't remember exactly) is fine in the winter.

I recommend two things:
1. Go fly.
2. Enjoy.
 
Jim Percy said:
I'm sure I'll be soundly rebuffed by the "oil temps must go over 210 degrees on every flight" crowd, but my XP-360 manual shows the "normal operating" range down to 130. Others have posted that Lycoming says ~160 (don't remember exactly) is fine in the winter.
Click to expand...

Hopefully, this forum got past the 210 degree "thing" months ago. If anyone still thinks that it needs to be that high, then go back and read all the Lycoming literature, previous threads, etc.

L.Adamson -- RV6A
 
I have always been told that getting the oil temp above 160F was necessary to remove the acids and water from the oil. So to me the oil temps would ideally be above 160F and below 240F the top red line. The Lycoming thermostatic by pass valve is trying to make the oil temp 180F so I think oil temp between 160F and 210F is ideal and above 160 and below 240F out of the earlier range of 160to 210, is acceptable but not ideal. Lycoming says to keep the cylinders below 400F-425F in cruise for maximum cylinder life. So to me, CHT's below that are ideal and above that and below 510F the top red line are acceptable but not ideal. The numbers you quote seem to fall in the ideal range on all counts.
Good Luck,
Mahlon
 
Savvy Aviator Recommendations

I attended Mike Busch's seminar on engines at last summer OshKosh and here are my notes about his recommendations regarding temps:
Oil temps:
< 170F: moisture isn't purged
> 210F: oil oxidizes rapidly
180F < ideal oil temp < 200F

CHT should NEVER exceed 400F
if < 230F, poor lead scavenging
250F < ideal CHT < 380F

Cheers
 
I just bought my RV9 last month and have put about 15 hours on it now. Being new to me, I am constantly watching the gauges to see where they are averaging. At cruise and leaned, I am averaging 160-170 oil temps and about 370 CHT. That's with the 0-320 160hp in 15-25 degree OAT (fahrenheit).
 
Just as a point of reference, my oil temps always ran low (170 in summer) with the Van's gauge, when I switched to EI instruments the temp jumped up 20 degrees.
 
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