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How to keep engine warm when flying in winter

Cheap and effective idea from Sport Avation good for cables such as carb heat or in this case oil cooler shutter. Just drill a 3/16 hole lengthwise through a bolt of sufficient diameter (maybe 1/2?). Drill hole through firewall, add a couple large area washers and locknut. After cable situated fill in any (very minor) voids with your sealant of choice. Done.

Hollow bolts (already drilled) are available in different sizes. Saw one on a firewall with inner diameter of 5/16 or so. Super neat idea for many firewall penetrating applications. I wondered why we don't see that more often.
 
When I initially built the plane, I had a little aluminum plenum I'd built to mount on top of the 7 row Niagara cooler on my O-360. In the plenum, fed by a 3" scat from behind and above #4, I had a throttle controllable in the cockpit. This proved invaluable in managing oil temps. I could keep it above 150 or so, even in 0F OAT's. However, I always had marginal cooling in hot summer conditions. This year I upsized to a 4" scat. I had some improvement in summer temps, but not a tremendous amount, as it appears that the cooler area is the limiting factor more than the airflow through it.

Additionally, I made the throttle for the new plenum a tighter fit than the previous. It has allowed me to have higher oil temps with cold OAT's than previously. Yesterday, the OAT was around 8F, yet the oil was at 180F. CHT's were around 300.

With regard to CHT in the winter, the mixture knob provides the most impact, just as it does in the summer. Yesterday, I was loping around at maybe 19" MAP, but I could change CHT's from 250 to 300 just by going from 6 to 7 gph (guessing on those FF numbers).
 

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Still cold oil with cooler tapes off

I have both sides of my oil cooler taped with AL tape. Today I worked the plane hard with full climbs from 1500' to 500' and flew for 1.3 hours. My highest oli temp was 141 degrees. My cylinder temps were all in the 350-360 range and exhaust mostly was in the 1350 range with a top of 1450.

I havent taped off the inlets since my cylinder temps are ok. Any ideas to help make the oil hotter? Outside of moving the much needed muffler heat muff to blast onto the oil cooler rather than my frozen feet Im not sure what else to do.
 
I have both sides of my oil cooler taped with AL tape. Today I worked the plane hard with full climbs from 1500' to 500' and flew for 1.3 hours. My highest oli temp was 141 degrees. My cylinder temps were all in the 350-360 range and exhaust mostly was in the 1350 range with a top of 1450.

I havent taped off the inlets since my cylinder temps are ok. Any ideas to help make the oil hotter? Outside of moving the much needed muffler heat muff to blast onto the oil cooler rather than my frozen feet Im not sure what else to do.

Try pulling the scat hose to the cooler and tape it closed. Then put the hose back on. This should keep the air from even going to the cooler.. I suspect the aluminum tape still conducts some heat and this may help.
 
With regard to CHT in the winter, the mixture knob provides the most impact, just as it does in the summer. Yesterday, I was loping around at maybe 19" MAP, but I could change CHT's from 250 to 300 just by going from 6 to 7 gph (guessing on those FF numbers).

Are you saying a lien mixture is colder than a rich mixture? I had an issue with lug fouling from too rich on the ground so maybe I am being too aggressive liening.
 
Try pulling the scat hose to the cooler and tape it closed. Then put the hose back on. This should keep the air from even going to the cooler.. I suspect the aluminum tape still conducts some heat and this may help.

Tom, I wrote a response and then realized I dont have a scat tube to the oil cooler. It is mounted on the back of the baffle in the regular position. I have a plenum and maybe it works too good. Maybe I can modify the inside with some sort of insulation tape over the oil cooler. I will let you know how it goes.

As for now, I wish I was in Vegas!
 
Are you saying a lien mixture is colder than a rich mixture? I had an issue with lug fouling from too rich on the ground so maybe I am being too aggressive liening.

If you are LOP it’s cooler. Here is a pic from today and the CHT’s were still dropping from the climb. Actually went ROP to try and keep them higher.
 

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If you are LOP it’s cooler. Here is a pic from today and the CHT’s were still dropping from the climb. Actually went ROP to try and keep them higher.

Wow. I understood that exactly backwards. It is going to be crappy, cold, windy here for the weekend so I will try some sort of insulated plate over the oil cooler intake and see how that works along with leaving the mixture rich except on the ground. Thanks for the info. It is the stuff you think you know that gets you!
 
Just a reminder...given a standard vernatherm system, the cooler always has some oil flow.

The vernatherm bypass hole is open when cold, so part of the oil goes through that bypass, and the rest goes through the cooler circuit, regardless of temperature.

It's one reason some owners install a plunger and spring, remove the vernatherm, and put a ball valve in an oil line. Close the valve, zero oil cooling.
 
Tom, I wrote a response and then realized I dont have a scat tube to the oil cooler. It is mounted on the back of the baffle in the regular position. I have a plenum and maybe it works too good. Maybe I can modify the inside with some sort of insulation tape over the oil cooler. I will let you know how it goes.

As for now, I wish I was in Vegas!

Say it ain't so. :D:D
 
I have both sides of my oil cooler taped with AL tape. Today I worked the plane hard with full climbs from 1500' to 500' and flew for 1.3 hours. My highest oli temp was 141 degrees. My cylinder temps were all in the 350-360 range and exhaust mostly was in the 1350 range with a top of 1450.

I havent taped off the inlets since my cylinder temps are ok. Any ideas to help make the oil hotter? Outside of moving the much needed muffler heat muff to blast onto the oil cooler rather than my frozen feet Im not sure what else to do.
The main goal of getting the oil hot is to help remove moisture from the oil. While the conventional wisdom is 180F is a magic number at the oil temperature sensor, oil in other parts of the engine will go well above the oil sensor temperature. The moisture in that oil will vaporize, and be blown out the breather.

If you fly for an hour the way you have, at the temperatures you saw, you have accomplished the goal of getting the moisture in the oil hot enough to evaporate. When you land, I recommend opening the oil filler to let the residual moisture out, and then running an engine dryer.
 
I definitely wouldn't put it aft of the oil cooler. People have tried it before and there is still enough air circulation on the oil cooler that you won't be able to get the oil to 180 if it is on the back. Unfortunately if you want it to work right it has to go between the cooler and the baffle.

I suppose on the back side it would certainly be better than nothing but I seem to recall a thread awhile back where even then people couldn't get it above 180. Below is what mine looks like for reference. Gaps have since been sealed and the cable bent for security.

I decided that installing the oil shutter on the back of the oil cooler wasn't the best choice, so I found an even easier alternative....I just had my A&P/IA do it while he was doing my CI. He charged me $150 (I bought the shutter from AntiSplat), which I thought was a good deal. It's a very nice install...he brought the Bowden cable through the firewall and the knob sits next to my air/heat/ALT air knobs.

It works well...cable moves easily without binding. Yesterday, it was 70 degrees OAT, I pulled the shutter fully closed and was able to get the temps up to 200F. Fully open I was getting 150F.
 

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I decided that installing the oil shutter on the back of the oil cooler wasn't the best choice, so I found an even easier alternative....I just had my A&P/IA do it while he was doing my CI. He charged me $150 (I bought the shutter from AntiSplat), which I thought was a good deal. It's a very nice install...he brought the Bowden cable through the firewall and the knob sits next to my air/heat/ALT air knobs.

It works well...cable moves easily without binding. Yesterday, it was 70 degrees OAT, I pulled the shutter fully closed and was able to get the temps up to 200F. Fully open I was getting 150F.

Mac this is almost identical to my setup. Works awesome doesn't it! I may need to take mine off sometime in the next year and clean it up a bit though, it is starting to get a bit tight, probably from dirt/dust.

P.S. You might need to trim that corner so it doesn't hit the cowl, although your baffles may have more clearance already.
 
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