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Re: block heaters, A4
>I'm no aircraft (or any other) mechanic, but I've never had a car with a
>engine, either :-)
ah, yes, but that isn't really the point. All engines can experience this
>I can't see how warming the coolant could be bad for the engine if it is
>right after that. Sure, extra warming and cooling cycles (like if your
>on a daily timer, but you only drove once a week) would be wasteful,
>probably harmful, but let's talk about cold starts.
Audi's usually do great in the cold, so that itsn't really the problem-I
guess it's driving the car for the first few minutes that's rough.
The cooling and warming cycle isn't the problem. The problem is that, as
stated before, water vapor in the engine and oil forms rust on any
available surface. This, in aviation engines, is noted mostly at an
inspection when the menchanic finds a small amount of rust on the camshaft
lobes, and some of them can be worn past acceptable ranges because a tiny
rust coating forms, engine runs, and scrapes off rust, rust forms, engine
scrapes it off, etc etc.
>Reports I've read indicate up to 90% of engine wear occurs on cold starts,
>so this is something we want to avoid, right? If I'm not mistaken, large "horse
> blanket" heaters are used on small aircraft to heat the engines before
I always though the problem was that oil had come off parts of the engine,
and that the visc. of the oil at low temps causing oil to not reach parts
quickly added to the problem. Wouldn't using a block heater cause oil to
come off parts more easily because the oil would flow more off parts
because of it's lower visc. rating at warmer temps?
I don't think I've seen many of those. Usually most people have an
FBO(don't ask what FBO stands for, but it's sort of like a gas/service
station/dealer for planes) come out to their plane and warm the engine with
a propane heater that forces hot air into the engine compartment(sometimes
clean air is used to heat the cockpit too). For people who don't use an
FBO or don't have a personal propane heater, heater pads in the oil pan
heat up the oil.
Here's a nifty idea for people who want a nice, toasty warm inside. It's a
trick many plane owners use to keep cockpits and instruments warm to
prevent problems with instruments freezing up.
The trick is to get a small ceramic heater(120VAC or whatever), and attach
its' bottom to a large board about the size of the seat or whatver else
you're going to put it on. Run an outdoor(yellow/orange, 3 prong, of
course, NO LAMPCORDS :) from your house/garage/whatever to the car, and
each time you get home, set up the heater and plug it in.
However, DO NOT use the heater to heat the inside of the car to ANYTHING
even CLOSE to 60-70 deg F. This would require the heater to be on a lot
and increase the risk of fire. You'll need an outdoor thermometer or
something similar to keep an eye on the temperature inside the car. I
believe that most people set up the heater to keep the inside at 40 deg or
so, maybe lower, just to take the chill out of the interior. I think that
you're supposed to use a "low" heat setting so as to not blast anything
with sudden super-hot air(ie leather on steering wheel, cloth interior,
etc. and cause damage/fire. Make sure there isn't anything flammable in
the car(or course) and you may want to program a position for the driver's
seat with the seat all the way back. Aim the heater towards the front of
the car, not towards the back of the seat(or course)
This technique works well to keep the car interior a little less cold so
you don't freeze your ass off each morning until the heater kicks in. The
car will also reach your comfy temperature sooner. Just use a little
common sense when you set it up(ie, don't get a 2000 watt heater, use a
heavy duty ext. cord, and don't set the thermostat all the way up.) This
is designed only to warm up the car interior a _little bit_.
I take NO responsibility for any damage/injury and all that crap from you
using this suggestion. You're the one buying the stuff and setting up, not
me. Be very careful and don't cut corners setting this up. You screw it
up, it's your fault. Not mine. Sorry, stupid disclaimers are needed for
stupid Americans(not including you people :) that do just about
(WHOOPS! Just read a little farther and saw somebody's post about doign
exactly this-oh well. I gave you some details. Sorry for the extra mail)
>So perhaps we all agree that you _should_ prewarm an engine before starting
>in cold weather? So perhaps the Lycoming report could be taken in the context
>of "use a better method if available"?
I believe the suggestion of the article was to use a block heater for no
more than, say half a day, and to NOT use one if the plane(or car) is not
going to be used for any more than 2 days or something. Having a timer
that turned on your block heater at, say 1 am for drive in and 3-4 pm for
drive home might be good, but that's just a guess. I'm sure someone has
found the "best" timing.
As for a better meathod-I don't know of any alternative to this sort of
thing-maybe oils will come out that will react or do something with the
water to keep it from causing rust.
>Anyway, I've used block heaters for years, along with oil-pan warmers, and have
>squeezed 400,000km out of a GM V6, 250,000 out a second one (different
>and 170,000 out of the present turbo alloy 4 cyl. and have never done any
>engine work (the only engine work I've ever done involved the timing belt's
>vaporization on the present car) and have never had to add (Mobil 1) oil
>changes. As far as I know, the first two engines are still running.
>Maybe those old V6s are rusty inside, but it must be rust where it doesn't
I think that it's mostly that people were noticing the problem when the
block heater was being used for long periods before any activity.
Also, at regular intervals(not sure of length) the engines in planes are
inspected thoroughly, and on a longer interval the engine is essentially
dissasembled, inspected+tolerances measured, then re-assembled if
everything is OK. The tolerances in an airplane engine are msot likely
much more lower than in a car engine. In addition, airplane engines run
hot at high rpm's for long periods of time under a very heavy load (sorta
like driving your car's engine at a constant 5,000 rpm or higher _all_ the
time, going up a steep hill trailering big boat for, say, 1/2 hour to 3-4
or more hours with no break) Most car engines are not designed to do
that-they are designed to run in the "normal" range of 2000-3000.(My manual
recommends no lower than 1500, shift at 3000, but, that wouldn't be much
fun if 3000 was the limit, now would it? =) One thing with the high
temperatures is a problem that happens on decent. When engine load is
greatly reduced, the heat generated goes down considerably, and at the same
time, if the pilot allows the airspeed to get too high or leaves engine
cooling flaps open, shock cooling occurs and the pistons get very tight in
the cylinder...Is there a similar problem in racing?