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Oil temp question

Bsquared

Well Known Member
I have a stock IO-390 but with the 5" oil cooler duct from the new baffle kit. I did my Phase 1 this past winter in relatively mild Southern California conditions with the OAT generally in the 50 deg range. My Oil temp was always rock solid at 180 deg and never over 190 during steep climbs. A few months ago during the Spring I dropped my airplane off at the paint shop and picked it up last week in the middle of a blazing hot summer heat wave. Today I did a one hour cross country flight and the OAT was 84 Deg at 7500'. I had difficulty keeping the Oil temp below 195 in Cruise or below 205 in a step climb regardless of mixture settings. My question is..... are these normal temps for a low time (40 hour) engine in high OAT/Density altitude conditions? Also, CHTs have remained below 350.
 
I have the older 4" duct baffling on my 390 and these temps are essentially what I see on a hot day at cruise (160-ish true). I imagine out in the desert temps mine would be higher.
 
.....OAT was 84 Deg at 7500'. I had difficulty keeping the Oil temp below 195 in Cruise or below 205 in a step climb regardless of mixture settings. My question is..... are these normal temps for a low time (40 hour) engine in high OAT/Density altitude conditions? Also, CHTs have remained below 350.

Normal. Very good really. Go fly.
 
Thanks for the replies. The other post I was directed to had all the answers I needed. I had done a search but did not find that one.
 
I have a stock IO-390 but with the 5" oil cooler duct from the new baffle kit. I did my Phase 1 this past winter in relatively mild Southern California conditions with the OAT generally in the 50 deg range. My Oil temp was always rock solid at 180 deg and never over 190 during steep climbs. A few months ago during the Spring I dropped my airplane off at the paint shop and picked it up last week in the middle of a blazing hot summer heat wave. Today I did a one hour cross country flight and the OAT was 84 Deg at 7500'. I had difficulty keeping the Oil temp below 195 in Cruise or below 205 in a step climb regardless of mixture settings. My question is..... are these normal temps for a low time (40 hour) engine in high OAT/Density altitude conditions? Also, CHTs have remained below 350.

Just a thought . . . if it was 120F OAT then the system is within expectations, but at the same time, the balance between oil and CHT would seem to allow some tweaking to reduce air bypassing the engine, thereby creating higher upper chamber pressure and pushing more air through the oil HX.

If you did everything by-the-book already, then some attention (tweaking) to the air around the heads/barrels could lower the oil temps and not affect the CHT (not in the book).

What you say? A flashlight, a tube of RTV and an extension tube to allow RTV application in some hard to reach areas - esp - intersection baffles under/between the barrels.

IMG_1801.jpg
 
I have a stock IO-390 but with the 5" oil cooler duct from the new baffle kit. I did my Phase 1 this past winter in relatively mild Southern California conditions with the OAT generally in the 50 deg range. My Oil temp was always rock solid at 180 deg and never over 190 during steep climbs. A few months ago during the Spring I dropped my airplane off at the paint shop and picked it up last week in the middle of a blazing hot summer heat wave. Today I did a one hour cross country flight and the OAT was 84 Deg at 7500'. I had difficulty keeping the Oil temp below 195 in Cruise or below 205 in a step climb regardless of mixture settings. My question is..... are these normal temps for a low time (40 hour) engine in high OAT/Density altitude conditions? Also, CHTs have remained below 350.

People dream about oil temps like that. I fly a Maule M7, and regularly get up to 235 in a climb, then maybe they cool down to 210 to 220 in cruise, and 205 in a descent.
 
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