Preheating engines: Airplane engines versus auto engines

This time of year here in the Northeast US I always preheat my Bonanza's
IO520 engine with a Tanis heater and an insulated cowling/prop cover as it
sits in an unheated t-hangar. The result is that the oil temperature at
startup is around 105 degrees F, even if the outside air temperature is as
low as -15 degrees F.

Monday night I arrived at my t-hangar to discover that at some point during
the day the line person accidentally pulled out the plug connecting the Tanis
heater to the small extension cord I use to extend the plug to the outside of
the cowling cover, so the aircraft had not been preheating. Outside and
inside temperatures were both a cold 25 degrees F.

Given any other day, I would have plugged the aircraft back in and scrapped
the flight but in this case I had an Angel Flight patient waiting in another
city for my arrival and I was already late. Thus I made the painful decision
to start up the aircraft and allow it to low idle until the oil heated
thoroughly. A small consolation is that the engine had been recently filled
with fresh Exxon Elite oil. To my relief the aircraft started right up.

I know what I did has negative long term repercussions on my engine's health
and I have already derived a tool to lock the two cords and prevent this
accidental unplugging from happening again. However, this leads me to
question the differences between aircraft engines and auto engines:

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?

--
Peter

In a previous article, "Peter R." said:
Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?



Aircraft engines are air cooled, auto engines are liquid cooled.

The following is what I was told when I was driving a Volkswagen Beetle,
and the experts were saying that you needed to let the beast idle for at
least 5 minutes in the winter:

Liquid cooled engines stay in a very narrow temperature range while
operating, so are built with very tight tolerances, but air cooled engines
have more slop because they get both hotter and colder than liquid cooled
engines. Also, they are cooled primarily by the engine oil. Because of
that, you need to preheat the engine enough that the oil is spread around
and everything has warmed enough that the pistons are making good contact
with the cylinder walls.


--
Paul Tomblin http://blog.xcski.com/
"The day Microsoft makes something that doesn't suck is probably the day they
start making vacuum cleaners" - Ernst Jan Plugge

On Dec 19, 9:35 am, (Paul Tomblin) wrote:
In a previous article, "Peter R." said:

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?

Aircraft engines are air cooled, auto engines are liquid cooled.

That may affect the time it takes for the oil to heat up but certainly
both engines start at the same temp. I think the question relates to
the lubrication ability of sluggish oil at start. In addition, I'm not
sure that an aircraft engine at idle really displaces much more heat
than a car engine with the thermostat closed in the cold. How much air
really moves over the cylinders of an idling aircraft engine?

-robert

On Wed, 19 Dec 2007 17:35:50 +0000 (UTC),
(Paul Tomblin) wrote:

In a previous article, "Peter R." said:
Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?



Aircraft engines are air cooled, auto engines are liquid cooled.

The following is what I was told when I was driving a Volkswagen Beetle,
and the experts were saying that you needed to let the beast idle for at
least 5 minutes in the winter:

Liquid cooled engines stay in a very narrow temperature range while
operating, so are built with very tight tolerances, but air cooled engines

Careful here. Don't confuse tight tolerances with tight clearances.
Aircraft engines have tighter tolerances than automobile engines.
Automobile engines have tighter clearances, but wider tolerances than
aircraft engines. If my car engine had the same fit as my IO-470N
it'd be considered worn out.

Roger (K8RI)
have more slop because they get both hotter and colder than liquid cooled
engines. Also, they are cooled primarily by the engine oil. Because of
that, you need to preheat the engine enough that the oil is spread around
and everything has warmed enough that the pistons are making good contact
with the cylinder walls.

"Peter R." wrote
...
...........................................
Outside and inside temperatures were both a cold 25 degrees F.

Given any other day, I would have plugged the aircraft back in and
scrapped
the flight but in this case I had an Angel Flight patient waiting in
another
city for my arrival and I was already late. Thus I made the painful
decision
to start up the aircraft and allow it to low idle until the oil heated
thoroughly. A small consolation is that the engine had been recently
filled
with fresh Exxon Elite oil. To my relief the aircraft started right up.

I know what I did has negative long term repercussions on my engine's
health
................................................. .....
Peter



This is joke post, right????
You're killing your engine because you started it at 25
deg???????????????????????????????????
ROTFLMAO
I'm sorry, I'll shut up now.

On 12/19/2007 12:39:10 PM, "gpaleo" wrote:

This is joke post, right????

Yes, it's a joke. You can go back to bed now.

--
Peter

Peter R. wrote:
On 12/19/2007 12:39:10 PM, "gpaleo" wrote:

This is joke post, right????

Yes, it's a joke. You can go back to bed now.


No, 6 year-olds should be in school by mid-day, not playing on mommies
computer!

"Matt Whiting" wrote
news

Peter R. wrote:
On 12/19/2007 12:39:10 PM, "gpaleo" wrote:
This is joke post, right????

Yes, it's a joke. You can go back to bed now.


No, 6 year-olds should be in school by mid-day, not playing on mommies
computer!

As a 6 year-old mechanical engineer of some 30 years practice and owner of
an IO-540 equiped airplane, I find it somewhat disturbing that the OP was
NOT a joke.
Anyway, pat on the back - big hug time for the courageous aviator who
started his engine at **GASP** 25 F, after careful deliberation on aborting
the flight until Summer.
Catch my drift??

"gpaleo" wrote in message
news:1198154485.901022@athprx03...
"Matt Whiting" wrote
news
No, 6 year-olds should be in school by mid-day, not playing on mommies
computer!

As a 6 year-old mechanical engineer of some 30 years practice and owner of
an IO-540 equiped airplane, I find it somewhat disturbing that the OP was
NOT a joke.
Anyway, pat on the back - big hug time for the courageous aviator who
started his engine at **GASP** 25 F, after careful deliberation on
aborting the flight until Summer.
Catch my drift??

Perhaps with your extensive and pontifical experience you cold summarize the
findings of Shell, Chevron, and TCM of the percentage of wear that occurs in
the first 30 seconds of cold (ie, below 40 degrees) starts?

gpaleo wrote:
"Matt Whiting" wrote
news

Peter R. wrote:
On 12/19/2007 12:39:10 PM, "gpaleo" wrote:
This is joke post, right????

Yes, it's a joke. You can go back to bed now.


No, 6 year-olds should be in school by mid-day, not playing on mommies
computer!

As a 6 year-old mechanical engineer of some 30 years practice and owner
of an IO-540 equiped airplane, I find it somewhat disturbing that the OP
was NOT a joke.
Anyway, pat on the back - big hug time for the courageous aviator who
started his engine at **GASP** 25 F, after careful deliberation on
aborting the flight until Summer.
Catch my drift??

He never said anything about "killing" his engine. He is certainly
worrying more than necessary, but that is no worse than your overly
melodramatic and condescending response. Actually, your response was
worse as his was made from ignorance and yours was intentional.

Matt