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Topic-icon Low oil temp ?

  • Kent Dellenbusch
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2 years 10 months ago #823

Am I the only one?
I own a 1989 Piper P28R-201T (Turbo Arrow). It has a TSIO 360-FB Continental engine. The problem I have is low oil temp in cruise along with low cylinder head temps again in cruise.
I’m looking for other Arrow owners that have had the same problems and what they were able to do to fix it.
Some History:
The previous engine developed rust on the cam and lobs because the oil temp was not hot enough to boil out the water. The plane was flown on a regular basis and the engine only went to 925 hours. I used the Continental recommended oil which is Phillips XC 20W 50. This oil has no anti-rust protection.
I then purchased a new Reman Continental engine and had it installed last June. Have the same issues with it and have been working with Continental Motors for a solution.
Put the cold weather plate on the oil cooler on the new engine. It blocks 1/3 of the oil cooler vents. Even in warm weather the oil temp was 135 to 150 degrees in cruise. The normal range is 170 to 180.

Took the plane to Fairhope Al. Continental’s engine shop December 8, 2015. They worked on it for 3 days ½ days.
1. Replaced the oil cooler and veratherm. Results: No Change.
2. Blocked off the lower Cowl vents with metal tape. Results: No Change.
3. Reset fuel pump. Results: No Change.
4. Took off the Merlyn Black Magic turbo and put the stock “pipe and bolt” turbo back on.
Results: No Change.
5. Blocked up the air intakes behind the prop and did a static ground test. Results: Oil temp and Cylinder temps came up to normal.
6. Last fix was that they installed metal take on the oil cooler vents to block another 1/3, now a total of 2/3 of the oil cooler vents are blocked. Results: Oil temp are now in the normal range in cruise however the cylinder head temps are still low.
With 2/3 of the oil cooler vents closed the oil temps run about 170 to 180 in cruise. In a normal climb from sea level to 18,000 feet they do get up to 200 to 205,, 33”, 2450 rpm, 75% power, 105 Kias. Ground temp was 70 and 24 at 18,000 feet.
Attached are pictures of the plane. The two upper cowl vents with red decals measure:
The lower cowl vents measure:
The opening behind the lower cowl and fuselage measures about 2 ½” by 22”.
Stock engine and airframe. Stock upper engine baffling.

Recent flight test,, Sometimes Cylinder head temps are a little cooler,, At LOP even cooler, #5 and 6 can be 270.
CYL#3 at 100 Degrees ROP (Peak 1520, 100 ROP-1420)
1. 1385 306
2. 1399 317
3. 1416 327
4. 1434 323
5. 1451 313
6. 1462 305
KIAS 132, RPM 2270, MP 32, OAT 55, GPH 12.5, TIT 1490, Oil Temp 153

John Moeckel


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2 years 10 months ago #825

Hi John,
In my Seneca 2 I have two Continental TSIO-360-EB's (one is an LTSIO-360-EB). I have 1/3 of each of my oil coolers blocked with the winterization plate and one seems to be enough although it would stay a bit warmer with two and I have thought about it. I think the difference between my Seneca and your Arrow is that I have cowl flaps and I don't think you do. If I open the cowl flaps in the winter you can watch the oil temps drop immediately. Obviously I don't open them in the winter. Also, regarding CHT's: at 31" of power (and 2400 RPM) I'm leaned to 11.5 gallons per hour and my CHT's stay right up there. What are you leaned to?

Good luck,

Scott Sherer

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2 years 10 months ago #836

Hi Scott,

Thanks for responding. You are correct,, no cowl flaps on my Arrow. Apparent cost cutting at Piper. I think that would help a lot to manage the cyl temps.

The recommendation from Continental when running ROP, is that you run the engine at 75 to 100 degrees rich on the hottest cylinder, which is #3 on this engine. At 65% power, I run at 32 inches and 2300 RPM. At lower altitudes I generally get the temps that I listed. At higher altitudes like 12,000 to 15,000 feet the cylinder head temps are 10 to 25 degrees higher.along with a little higher oil temp. Here in Florida I seldom fly over 8,000 feet, however out west, I'm in the range 12,000 to 15,000 most of the time. So the only thing that has worked on getting the oil temp higher was to block off that additional 1/3 of the oil cooler air inlet., for a total of 2/3's. Nothing has worked on getting higher cyl temps, except for a static run up with the air intakes behind the prop blocked.

When you say you get the cyl temps up when leaning to 11.5 gph, what degrees of ROP are you?

When I run LOP (GAMI Injectors), the cyl temps are another 10 to 20 degrees cooler.

Continental is telling me that cyl head temps between 270 and 300 i cruise are not a longevity or operational concern.

Again, Thanks so much for your input.



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2 years 9 months ago #837

Scott & John,
Very interesting discussion, as I too have wondered why the TSIO360KB engines in my Seneca III always run such cool CHTs and oil temps in the 150-160F range. I recently read an engine article where the author espoused that if you maintain at least 180F oil temp and use your aircraft regularly, your engine will always make TBO, with emphasis on the 180 temp, which as you noted is needed to boil the moisture off the oil. My winterization kit is the same as yours, covering one third of the oil cooler top surface. I am going to cover another third with metallic tape.

As printed in the December Piper Flyer which featured my airplane, I always cruise at ~65%, 31"/2400 rpm, and lean to 1590F TIT which typically yields ~12GPH/side (no Gamis, and if I try to lean more aggressively the TITs get over 1600F!) CHTs during most of the year in E. Canada are in the high 200s. Winter Florida trips, and summer in Canada yields CHTs in the low 300s, with hot day climbs maybe reaching 350!

Enjoyed your posts.

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