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Cold oil temp fix needed

N

N4263M

Registered User
Minnetonka, MN
Now that winter is sort of arriving in Minnesota, we are having trouble getting the oil above 140 in our PA-12.
O-320 with rear mounted oil cooler taped over.
Foam blocking exit air where the cowlings close (see pic).
7c973495d4c83050bcabc408036761b3.jpg


We do have CHT/EGT gauge, but I really get nervous about blocking inlet air.
Anybody have more tricks we can try?
Thanks


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How much flying are you doing? How often are you changing it? Are you using camguard? 4 cylinder or single cylinder EGT/CHT? Are you leaning out when you fly? Man I must have some strong coffee for that many questions this early.:smile:
DENNY
 
Just had an expression, so ready to answer your volley:
Flys at least once a week.
Oil changes at 50 hours.
Have not used camguard, but maybe helpful?
4 cylinder EDM 700.
I don’t usually lean, rarely above 2000msl.

Even on floats in the summer it would barely get to 180.


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N4263M said:
Just had an expression, so ready to answer your volley:
Flys at least once a week.
Oil changes at 50 hours.
Have not used camguard, but maybe helpful?
4 cylinder EDM 700.
I don’t usually lean, rarely above 2000msl.

Even on floats in the summer it would barely get to 180.


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Click to expand...

How many minutes did you fly to get to 140? What was the OAT? High power? Low Power? If you climb...say 3000'...@ 65MPH....what does the temp get to?

My 0-320 with the front mounted cooler takes a looooong time to get to 180 when it is 20 degrees out, even with it blocked.

Lets see some pics of the tape over the cooler and the front of your cowling.
 
My planes haven't made 180* in winter even with the coolers blocked. I don't restrict intake air because CHTs don't allow it.
 
That makes me shudder seeing all that blocked off.

Tape over the cooler, restrict the inflow little by little starting beside the prop to keep the case and base warmer. One strip of tape at a time.
 
Last 24 years flying in winter I get about 100F over ambient on my little C engines. So some days it never gets to 90F on the gauge that been checked for accuracy. Never seemed to bother anything but I fly every weekend.

Glenn
 
My advice take with grain or shaker of salt as needed. Lean to CHT of 325 or less whenever you fly, use Camguard, If CHT greater than 325 pull that foam crap out. Water and oil make mayonnaise. If you really are building up a lot of water in the oil it will show. Put a pot of water on the stove at 140 degrees and see how long it lasts. If you are really worried just change oil at 25 hours. I do a fair amount of winter flying, when it is below zero my oil temps seldom get above 160 I have not seen any sign of moisture buildup in the oil. 180 degrees is what most (including me) recommend, but I don't risk CHT to reach that temp.

On a historical note, common thinking in the old days was the engine/CHT temp was always close to oil temp. With onset of more people using 4 cylinder CHT/EGT we find this to be untrue. So be carefull of advice to only worry about oil temp.
DENNY
 
In the old days there were jackets which fit over the kidney tanks on the small Continentals for this purpose. Perhaps something similar could be fitted over your sump? There is a lot of aluminum on that sump which wicks the heat away.
 
For a number of years, I used removable plates at the rear of the cowl cheeks to increase oil temps on a really cold running engine. But, when I say “a cold running engine” I’m talking oil temps at 100 F on a calibrated gauge. Those baffles got oil temps up to about 140 F.

if you’re getting oiltemps to 140, that may be as good as it gets in cold temps. As Denny noted, change oil frequently and use Cam Guard.

And then run the hell out of it. I see a lot of folks running very low power settings, for a variety of reasons. These engines were designed to make some power, and more power equals more heat.

MTV
 
Hello I was wondering what max cht temp you guys use on climb and Cruze my plane has a 0- 360 and only has single cht probe on #3

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Rman

I believe the red line max temp according to Lycoming is 500 degrees.

Engine experts seem to feel that if you can keep your CHT's below 400 degrees most of the time, especially in cruise, you will see increased engine longevity.

I believe the spark plug method of CHT monitoring tends to read on the high side.

Hope this helps

Bill
 
Last edited:
Yes I does I blocked part of my oil cooler off and covered off a portion of the hole in the bottom of the cowling my oil temp runs @180 and my cht runs @390 or just below 400. I do have a bayonet style probe. When I climb it will go over 400 quite quickly. I wanted too get your options if this was ok or should I not be blocking the lower cowling off at all. Thanks for the help

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If you are trying to keep the oil warm block off all of the oil cooler not just part of it. No reason to keep the CHT'S that by blocking off bottom cowling.
DENNY
 
Ok thanks I wasn't sure if I should block the oil cooler off completely

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" I believe the spark plug method of CHT monitoring tends to read on the low side. "

Bill, I think you're wrong on this. When I went from the under the plug style to the bayonet style I found they were about 50 deg high

Tim

 
2794826bc3554d18002198c83061ee1d.jpg


Update following further experimentation:

1. Found oil cooler plate from a previous airplane. Installed on front of oil cooler with approximately 80% coverage.
2. Removed foamy things from cowl cheeks.

Photo shows new oil temp at cruise at 2400 rpm.

New question: assuming the gauge is accurate, is that an acceptable oil pressure at 2400rpm?

Thanks, Tom



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