High Oil Temp...

[NinerBikes]

Well, Jim, running full synthetic Mobil 1 4T motor oil and Mogas that's free of lead and up to 250F oil temps seems to be OK, if only done on occasion? I'd keep an eye on oil temperature, myself.

I ran Mobil 1 4T exclusively with Mogas, and almost always tried to keep my oil temps at 230F or less, not letting it get into the yellow range. Summer time and 1800 to 2000 feet AGL is all I would get, before backing out of throttle to 5000 rpm and level flight to cool down my oil temps. Those were personal limits I set, myself.

Biggest problem was that summer time around here almost always had temperature inversions that caused 4000- 5500 ft of altitude climbing necessary to get to the cooler atmospheric air above. Takes a long trip to make it worth the climb.

[seagull]

Has anyone found a larger oil cooler that fits the -12?

I know other planes with the 912 have larger coolers.

I would think that would solve the heating issue in hot climates.

[bobg56]

If I was getting up to 250F I'd verify the oil temp using a Laser thermometer or dip probe into oil tank or maybe change out temp sensor

[Piper J3]

As a follow-up to my original post #1… I modified the lower cowling to move the oil cooler 1” forward. Worked a charm… Now in cruise flight, at 75 OAT, I see 207F oil temp. I should have no problem staying in green arc with exception of long climb on really hot day.
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[NinerBikes]

Too bad the mold for the original lower cowling didn't take this into account. Fiberglass is really itchy work. Plus if your lower cowling is already painted, more rework.

[seagull]

[quote=Piper J3;1614662]As a follow-up to my original post #1… I modified the lower cowling to move the oil cooler 1” forward. Worked a charm… Now in cruise flight, at 75 OAT, I see 207F oil temp. I should have no problem staying in green arc with exception of long climb on really hot day.
-[/QUOTE

That is an amazing change from your previous numbers of 231f with OAT of 68.

I also have a 1" gap between my muffler and cooler. At 75f OAT, level flight, 5400 RPM, 118 TAS, gross weight, I have 235f on the oil temp.
I can lower the oil temp to 220f if I lower the RPM to 4800 but that drops the TAS to 105 KTS.

[Tony_T]

Jim,
Good report and nice neat work on the cowl!

[Piper J3]

Originally Posted by seagull

I also have a 1" gap between my muffler and cooler. At 75f OAT, level flight, 5400 RPM, 118 TAS, gross weight, I have 235f on the oil temp. I can lower the oil temp to 220f if I lower the RPM to 4800 but that drops the TAS to 105 KTS.

There is a “Heat Dome” forecast for Tues/Weds with temps in the mid-90’s. I’ll fly then and report-out with data….

[NinerBikes]

Do you have to replace the oil hoses to the oil cooler to allow for additional distance?

[Piper J3]

Originally Posted by NinerBikes

Do you have to replace the oil hoses to the oil cooler to allow for additional distance?

No, hoses have enough slack to accommodate without stretching....