Will I hurt my engine?

McBuzz

McBuzz

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Dec 9, 2006
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Buzz
I'd like to fly tomorrow, Citabria 160 HP engine. The problem is the temperature is supposed to be 0-5 degrees F. The engine will be pre-heated to approximately 60 F. prior to flight. However, twice before, when I have flown at these temperatures, once in the air, the oil temp. never reads above 120 degrees. All other temperatures (EGT, CHT) are fine. At OAT's above 25 degrees, oil temps. are about 130 - 150.

Any input would be helpful. There are some folks who fly Champs and Cubs on skis in the same weather at my airport and I know at least one of them has no special engine weatherization. By the way, I use multi-weight oil and I'm told that should be OK.
 
I'll have to order that in "winter weight".
 
Get a space heater and warm up the cockpit real good before you fly. Most people forget that the cold temps can really hurt the gyros. I put my under the inst panel to let the heat rise up. A good warming period of 30-60 minutes really helps. Plus it warms up the seat before I get in.

Of course all that is moot if you are in a heated hangar. My hangar is not.

Also make sure you have preheated your engine.
 
Thanks Scott. I use a sizable propane heater that warms the engine and cockpit. All instruments function properly from the start.

Diana, I'd love to do a few loops and rolls tomorrow (just purchased a parachute), but I agree, probably not a good idea at those temps.
 
What Ken said. Duct tape is the poor man's winterization kit. Won't hurt anything, unless you put too much on and your temps go too high. Easily removed when temps rise. What's not to like?
 
Ken Ibold said:
Cover half of the oil cooler with a strip of duct tape.
Click to expand...

Just to expand one note on that, please don't take as a "well duh" insult, but make sure when you tape off part of an oil cooler, you put the tape strips perpendicular to the tubes so all the tubes have covered and clear sectors. At very cold temps, you can often cover the whole thing.
 
A bit of clarification never hurts. It's the after the fact "well duh" that really smarts.
 
Buzz,

(I didn't make the connection until now.)

4AC had an oil cooler cover plate when it was delivered from the factory. I thought it was in the seat pocket when I turned it over to Larry. I'll look around in my hangar stuff to see if it is lying around here. It's a square of aluminum about 4x4 inches with a couple of holes in it.
 
Ken,

Thanks. Needless to say, I've been through every part of that plane thoroughly and don't recall seeing a cover like that. I'm getting ready to head out to the airport now and I'll re-check all of the pockets.

Buzz
 
Move to someplace warm, then this debate becomes moot ;). [/sarcasm]
 
Relatives in San Antonio have made the same suggestion.
 
Make sure you either get the engine nice and warm with the preheat, or that you let the engine idle for a few minutes before you rev it up.

Think about it - when you shut the engine off, the oil is warm. Warm oil is runny - meaning it gets to places other than where it needs to be. When the oil cools, it gets thick. Meaning that it takes it a little while once the engine is restarted for it to get back to where it needs to be.

That is also good advice for your car in cold weather - give it a minute or so for the oil to get out of the base. Makes a big difference.

I'm actually not sure how much that applies to airplane engines, but it can't hurt!
 
Obi Heed Kenobi said:
That is also good advice for your car in cold weather - give it a minute or so for the oil to get out of the base. Makes a big difference.
Click to expand...
I have a block heater for the truck. Solves lots of problems in the cold WX. Truck starts easier, gets warmer faster, and melts that snow off of the hood!
 
My only experience is with my 140, which has a C90 continental.

Check local listings, but here's what I've found to be effective. These techniques are known to be effective and not detrimental to the engine in my aircraft.


1) install a Tannis heater on the oil pan. Give it at least 4 hours to get up to temp. If you fly a lot and keep fresh oil in the engine (20 hr changes for me in the winter), it's tolerable to leave the heater plugged in all the time on small Continentals.

2) cover the oil pan cooling inlets (Cessna actually makes covers for this purpose, but most guys still use duct tape)

3) cover up to 40% of the main air inlets with aluminum plates (I think Cessna has recommendations for this as well)

4) Remove the little fixed "cowl flap" at the base of the cowl.

I've found the "winterized configuration" adequate for cruising around in temps of as low as 10 deg F. Below that, and I don't see oil temps rising high enough to cook out the water. Plus, I don't have a "driver's side" door seal, so the cabin gets a little chilly.

I'm sure people use similar techniques on all piston aircraft. Blocking the main air ducts is obviously the most "delicate" piece of the puzzle, since doing it excessively or improperly could destroy a cylinder in minutes. If you're blocking the main air inlets, cover the inner portion of the inlet, leaving an unobstructed flow path over the cylinder heads, which need cooling the most. No matter what you do to winterize your aircraft, keep a close eye on CHT/EGT and oil temp, and do not leave your winterization mods on when temps get above 40 or so.

I try to be "thermally considerate" to my engine all the time, but especially when it's really cold. That means cruising for at least few minutes after a long climb, and descending slowly, at or slightly below cruise power.

I believe Tannis has a lot of good info on winter operation. Continental also has helpful technical documentation that, though tailored to their line, is mostly applicable to all conventional air-cooled aircraft piston engines. Finally, there was a helpful pilotcast episode on winterization.

The big idea is to make your engine run the same as on a nice spring or summer day. If you keep the temps the same in the winter as in the summer, the engine won't care what the OAT is.

I'm not sure if that answers any questions, but I'm waiting for a commercial flight after a long day and this is what I felt like typing. :dunno:

Matthew
 
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