High Climb Out Oil Temps

[bucko]

 

I just returned from Colorado and experienced high oil temps on climb outs (especially at high altitude airports). Would see 220's and ended up doing step climbs: 120 MPH IAS (not knots) with EGT's about 1,250.

 

1965 M20--E with I/O 360.

 

CHT's were all about 320-340, except for #3 which maxed out at about 374.

 

Going to LOP at altitude, oil temp back down to 196-199. All CHT's were lower, with #3 about 354.
(Please, no LOP vs ROP discussions- I go from fuel flow of 10 down to 8 gph with LOP losing only 3 knots TAS, and all my temps are better).

 

What EGT should I climb out at? Any other suggestions for management of climb out high oil temps? Oil levels were normal, and oil change done prior to the trip. (So it was new and clean.)

 

Also, JPI matches old Mooney oil temp guage still in original cluster.

 

I did read the article on "Target EGT" found at http://www.advancedpilot.com/tech.html , but was unsure as to how to calculate it for my E model.  Looking at the chart for the M20-J, it looked like about 1,325 degrees.

 

Any comments or insights would be appreciated.

 

Bucko Strehlow
M20-E

 

[carusoam]

220dF is high for your plane?

The reason that I point this out is that is barely above the point of boiling water and really far away from thermally degrading the oil.

Of course, heating the oil higher than usual is not without costs. Localized oil temps around the exhaust valve stems will be higher.

The following discussion is for climbing. Not to be confused with cruising. The engineering and economics will be different for the two cases.

Things to consider...

0) the short time it takes to climb

1) Oil cooler location and it's airflow and oil flow through it.

- wash the external fins,

- clean the internals, and/or

- check it's operation including the valve that opens and closes the oil flow.

- increase airflow by increase in ASI, climb at 130 mph or 140...

- remove excess cylinder heat, open cowl flaps some more....

2) Lower the exhaust temperature

- by going richer ROP, 200 in place of 100. Use the blue box if you have one or white box if you go G1000!

- go leaner LOP. I don't go LOP in climb....

3) Lower the OAT.

- move North

- wait for a cooler day

Chances are, the hot OAT is causing all temperatures to rise some. Make some adjustments for the day.

The economy of the climb is relatively small. Go ROP to be nice to the hardware.

How does this sound? Did I miss something?

Keep in mind, I am only a PP, not a mechanic.

-a-

[DS1980]

I would consider a max CHT of 374 acceptable. I wouldn't concentrate on on EGT as much as on CHT. I think you're dong just fine.

[Guest]

Your 65 E with the dog house baffle set up is prone to many leaks where the metal meets the engine, find and seal with high temp RTV. The forward rubber seal which fits the groove in the cowl is likely old, stiff, missing parts, replace with new if needed.

Add sealant to the surface between the oil cooler and the lower cowl, assuming it is still at the front of the cowl.

Check and adjust cowl flap rigging.

Time spent will be worthwhile in lowering temps.

Clarence

[FloridaMan]

Nevermind. Just saw that you're using a JPI. I guess reading is fundamental. 

[rbridges]

I would consider a max CHT of 374 acceptable. I wouldn't concentrate on on EGT as much as on CHT. I think you're dong just fine.

 

I try to keep my oil temp at 210 or less.  Would you be okay with a higher oil temp if CHT stays under 380 or so?

[DonMuncy]

From what I understand, you want your oil over 212 F to boil off any water.

[Marauder]

From what I understand, you want your oil over 212 F to boil off any water.

You do, but where the temperature pickup for the oil temperature gauge resides may see a different temperature.

[Bob_Belville]

I have gotten very anal about oil temp but find it impossible to keep it below about 220 on climb out if the OAT is high and/or I start out with a warm engine (after a brief fuel stop). Frankly, the engine experts I've dealt with are not nearly as concerned about 220-230 as I am. They would be much more concerned about low temps.

[N201MKTurbo]

The oil cooler setup in the older cowls (I had an F for 19 years) is just bad. The air actually flows out of the front of the oil cooler in some situations.

 

I understand the Laser oil cooler relocation will help a lot.

 

When I added a cowl closure it improved the oil temps a little. 

 

Other then seeing the oil temp meter near the red line I never saw any ill effects from the high oil temps.

[Bob_Belville]

The oil cooler setup in the older cowls (I had an F for 19 years) is just bad. The air actually flows out of the front of the oil cooler in some situations.

 

I understand the Laser oil cooler relocation will help a lot.

 

When I added a cowl closure it improved the oil temps a little. 

 

Other then seeing the oil temp meter near the red line I never saw any ill effects from the high oil temps.

My '66 E has the cooler relocated to behind cyl 4, I had Pacific Cooler rebuild it at the last annual and check out the vernatherm valve. I replaced the baffle seals with the reinforced style silicone and I have used at least a tube of HT RTV to use seal every pinhole in the baffles which are the 201 style with a 201 style cowl mod. I climb at 115-120k or higher ias with full rich and cowl flaps open. 

 

Still OT can occasionally get to 220-225. What I have found is that pulling back power a little (FT, RPM to 2550) from balls to the wall after getting above pattern altitude helps a lot. Many years ago the wisdom was to pull back to 25 square for climb. While that is discredited today, there is no question in my mind that reducing power reduces OT & CHTs.

[N201MKTurbo]

In my 201 I still see 220 sometimes on hot days. The sensor I believe is in the front of the left oil gallery.

[Bob_Belville]

In my 201 I still see 220 sometimes on hot days. The sensor I believe is in the front of the left oil gallery.

The sensor on mine is at the rear near the vernatherm valve. I don't know if it is upstream or downstream of the cooler.

[rbridges]

I feel better about my temps.  It seems like a lot of people stay in the 180 and 190 range.  Most of the time, my temps stay in the high 190s/low 200s during cruise, but they will occasionally creep into the low 210s on hotter days unless I crack the cowl flaps.