Cold Wx contradictions

[AdamZ]

This morning I was thinking were always talking about preheating our aircraft engines before start up on a fridged day. Makes the oil flow, less damage to the engine etc. But we don't preheat our car engine ( well sometimes we do but not near as much) Is any less harm done to your car engine than an aircraft engine when we just pop in and turn the key? If so do experimentals with auto engines such as Subaru or corvair engines frequently used in home builts.

 

[alaskaflyer]

Au contraire, mon fraire! I preheat my car engines anytime it is much below 32F, unless I am not anywhere near a plug in. I have warming pads on my oil pan, my battery, and a block heater on both our vehicles. Also the auto transmission on my Subaru.

As for possible damage I will let more mechanically inclined folks chime in.

 

[Larryo]

This morning I was thinking were always talking about preheating our aircraft engines before start up on a fridged day. Makes the oil flow, less damage to the engine etc. But we don't preheat our car engine ( well sometimes we do but not near as much) Is any less harm done to your car engine than an aircraft engine when we just pop in and turn the key? If so do experimentals with auto engines such as Subaru or corvair engines frequently used in home builts.

Adam,

First of all, an aircraft engine is worth xxx times more that a car, but a lot of folks do heat there cars. I did when I was dumb enough to live in the cold weather, but not as anal as I was with the plane. Both had heated hangar/garage and a plug in.

When I fly, my SOP is heat below 32F.

Now, living in FL does help.....

 

[stagecoachco]

I have a subaru powered subaru :smile: that I never preheat. Every winter we get several days of below zero. Over 150,000 miles on engine with nothing more than routine mx (oil, spk plgs). Part of the difference might be the fact that in our autos we run multi viscosity oil. I use 5w30 in the winter.

 

[Geico266]

Au contraire, mon fraire! I preheat my car engines anytime it is much below 32F, unless I am not anywhere near a plug in. I have warming pads on my oil pan, my battery, and a block heater on both our vehicles. Also the auto transmission on my Subaru.

Ditto. My diesel truck is plugged in 24/7 (unless I'm driving it) below 40F.

 

[Geico266]

As for possible damage I will let more mechanically inclined folks chime in.

I can turn a wrench and read does that count?

The biggest difference is the typical aircraft engine block is made out of aluminum and shrinks around the cast iron crank, bearings, rods, causing more wear when it is started in extreme cold. As the engine warms there is a huge difference in expansion rates between the different metals. The movement of oil, while obviously important is the secondary concern to contraction. A good multigrade oil will flow sufficently to lubricate.

I preheat 40F.

JMHO

 

[acrodisiac]

One would think that air cooled engines with their much larger clearances would stand a better chance of living through multiple cold starts while auto engines with their much tighter tolerances would suffer more but they both suffer the same.

The difference is risk management really. If your auto engine clanks to a halt due to he affects of severe wear you end up on the curbside. If your aircraft engine fails due to the same affects-well - you know the consequences.

Remember also that auto manufactures go through rigourous cold wx testing to assure some reasonable level of reliabilty/startability under severe conditions chiefly because car drivers are way too impatient to start and go. Accelerated wear always occurs at start up, warm or cold , it just gets worse as temperatures drop and all metal shrinks and all oils thicken.

Cars are typically using 5, 10 or even 0W30 oils in cold climates. We use the equivalent or 20 weight oil in our least viscous multi grades. 20 still pours like molasses at cold temps.

Pre-heat and all engines live longer.

 

[Everskyward]

I have a subaru powered subaru :smile: that I never preheat.

Ditto. At home it is parked in an unheated garage, but at work is is parked out in the cold, sometimes in subzero temperatures. Generally I just start it up an go with no idle time. I've done this will all the cars I've owned and never had any problem.

 

[stingray]

It will not start unless it is plugged in.

A side from that I think it has to do with the same reason that a trainer that flys every day lasts longer than one that flys once a month. Cars generally start every day and usually every 8 to 12 hrs.

Dan