Today's Message Index:
----------------------
1. 04:15 AM - Re: Rotax 912 Preheating (FLYaDIVE)
2. 05:14 AM - Re: Rotax 912 Preheating (dashwood)
3. 05:47 AM - Re: Re: Rotax 912 Preheating (FLYaDIVE)
4. 08:43 AM - Re: Re: Rotax 912 Preheating (Gerry Visel)
5. 10:06 AM - Re: Re: Rotax 912 Preheating (FLYaDIVE)
6. 10:34 AM - Re: Re: Rotax 912 Preheating (Gerry Visel)
7. 04:01 PM - Re: Re: Rotax 912 Preheating (rayj)
Message 1
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| Subject: | Re: Rotax 912 Preheating |
Hi Raymond:
The theory is this:
There is water in the oil.
There is water condensed on the metal parts of the engine.
When the water freezes it creates ice crystals -
Some of these ice crystals are between parts such as connecting rods
and journals of the crank shaft.
When water freezes it expands - This puts uneven pressure on the connected
parts. Journals, guides and bearings. Squeezing out the oil.
If there is Water in those areas there is NO oil in those areas - So there
is the possibility of metal to metal ware.
This is the THEORY - It has some merit. But, Adam Ant has not gotten
inside the engine and taken pictures so I don't know 1,000%.
I do KNOW this: A pre-heated engine starts easier than a non-pre-heated
engine.
A plane that I fly, an RV6, won't even think of starting at temps near
freezing.
Which brings up a second theory:
Most aircraft engines have very sloppy tolerances between mating parts. If
you have a better than average engine with close tolerances and there
are dissimilar metals in contact (Steel and Aluminum) each metal has a
different coefficient of expansion. Aluminum expands more than steel. You
could put higher pressures and uneven pressure on mating parts.
Chose which ever theory you like - But, Pre-Heat. Your engine will like
you for it. And may even last longer.
Barry
On Wed, Nov 14, 2012 at 11:29 PM, rayj <raymondj@frontiernet.net> wrote:
> Please explain what the freezing point of water has to do with when to
> preheat an engine that is cooled with a combination of antifreeze and air.
>
> Raymond Julian
> Kettle River, MN.
>
> "And you know that I could have me a million more friends,
> and all I'd have to lose is my point of view." - John Prine
>
> On 11/14/2012 09:58 PM, FLYaDIVE wrote:
>
> Damien:
>
> Pre-heating is a function of FREEZING which starts at either 0 C or 32
> F. It is NOT a function of Manufacture. So unless ROTAX uses a different
> freezing point - - - Kelvin maybe - - - Start Pre-heating at the freezing
> point.
> Pre-heating is also helpful when it comes to PLASTICS. Many a knob and
> gear have become loose or broken when the temps drop. Personally - I begin
> to function slower as the temps get lower, so it is just as important to me
> to be Pre-Heated.
>
> Barry
>
> On Wed, Nov 14, 2012 at 10:57 AM, Damien <dgraham7@twcny.rr.com> wrote:
>
>> Hello Group.
>> There is an article in this month's EAA Bits and Pieces for Canada about
>> preheating engines. It mentions the temps that trigger preheating for
>> Continentals and Lycomings. I have not been able to find sugesstions for
>> the Rotax 912. Does anyone know what the temperature would have to dip to
>> require a preheat for the Rotax 912 ? Thanks.
>> Regards,
>> Damien Graham
>> N48TK
>>
>> *
>>
>> _blank">www.aeroelectric.com
>> .com" target="_blank">www.buildersbooks.com
>> ="_blank">www.homebuilthelp.com
>> _blank">http://www.matronics.com/contribution
>> ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List
>> tp://forums.matronics.com
>> *
>>
>>
> *
>
> *
>
>
> *
>
> *
>
>
Message 2
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| Subject: | Re: Rotax 912 Preheating |
some are getting close "dissimilar metals in contact (Steel and Aluminum) each
metal has a differentcoefficientofexpansion. Aluminumexpandsmore than steel.
You could put higher pressures and uneven pressure on mating parts. "
this is one of the main reasons but another is the oil... oil only.... there is
no water in an engine that runs often. one that sits for long perionds may...
may have some condensation filter in..... but its the oil... shelll sport 4
is like cement , or molassis , or thick glue.. at lower temps....it cant be
pumped or moved through a cold engine... try it ... a lot of metal clankin goin
on till the oil is warmed and if you dont pre warm it ... its the friction
from metal on metal that has to do the warmin up... . i have 100wat bulb on
under the engine cowl from now till spring... and a bear blanket wrapped on the
outside... live near detoit / toronto. any time the temp is below35/37 degrees
i change oil to 0w40amsoil syn. and use the light....at temps below 20deg
F i also us a propane heater for 30min .
no one has to pre heat... but everyone should..alway... these engines are a big
investment... try leaving $16000.00 at the curb and see if it needs warming
in at night... it will just leave mysteriously... your engine is the same
.. it will just leave you... one little part at a time... . all / any oil is
the same to varying degrees... some are using 50w .. put that in the fridge over
night and do a fluid test... it no longer is fluid...its rock hard.. 0wXX
will be better but still is not great..
--------
Ross Aalexander: CH701 driver 912ul 589tt
It only takes two things to fly, airspeed and money
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=387950#387950
Message 3
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| Subject: | Re: Rotax 912 Preheating |
Hi Ross:
There is always water in oil. Of course you reduce the quantity by flying
often.
An easy way to prove this to yourself is:
After a flight - Open up your Oil Cap. What do you see coming out? A
white vapor. That white vapor is water. Now, take a smooth sheet of
aluminum and hold it in the vapor. What do you see? Water condensing on
the aluminum.
Part of the normal COMBUSTION process is water -
http://en.wikipedia.org/wiki/Combustion
And as combustion gases get past the rings of the pistons they get into the
crank area of the engine. OIL is in the crank area of the engine and the
oil absorbs the water.
Another way of proving this is:
Do this out side.
Take a quart of NEW oil.
Put it in a glass jar.
Weigh the oil & jar - ACCURATELY - Gram Scale
Put another Larger Glass jar over the first.
Set up the second glass jar so it is raised an inch with 5 blocks around
the edge. It has to breathe - Just like an engine.
Let it sit OUTSIDE for a couple of months - [Requirement - You can't live
in the Sara Desert]
Weigh the oil & glass jar... Guess what?
It became heaver - WATER was absorbed into the oil.
Another proof:
In the cold weather - DURING PRE-FLIGHT - Slowly and carefully pull out
your dipstick (NO! Not that one!!!) - Look at the clear droplets that are
on it. That is water. If it is on your dipstick, it is in your engine.
If it is in your engine, it is in your oil.
YES running an engine does reduce the amount of water but not totally.
Hope this explains things.
Barry
On Thu, Nov 15, 2012 at 8:14 AM, dashwood <dashwoodlock@hotmail.com> wrote:
> dashwoodlock@hotmail.com>
>
> some are getting close "dissimilar metals in contact (Steel and
> Aluminum) each metal has a different=EF=BDcoefficient=EF=BDof=EF
=BDexpansion.=EF=BD
> Aluminum=EF=BDexpands=EF=BDmore than steel. =EF=BDYou could put
higher pressures and
> uneven pressure on mating parts. "
> this is one of the main reasons but another is the oil... oil only....
> there is no water in an engine that runs often. one that sits for long
> perionds may... may have some condensation filter in..... but its the
> oil... shelll sport 4 is like cement , or molassis , or thick glue.. a
t
> lower temps....it cant be pumped or moved through a cold engine... try it
> ... a lot of metal clankin goin on till the oil is warmed and if you don
t
> pre warm it ... its the friction from metal on metal that has to do the
> warmin up... . i have 100wat bulb on under the engine cowl from now till
> spring... and a bear blanket wrapped on the outside... live near detoit /
> toronto. any time the temp is below35/37 degrees i change oil to
> 0w40amsoil syn. and use the light....at temps below 20deg F i also us a
> propane heater for 30min .
> no one has to pre heat... but everyone should..alway... these engines
> are a big investment... try leaving $16000.00 at the curb and see if it
> needs warming in at night... it will just leave mysteriously... your
> engine is the same .. it will just leave you... one little part at a
> time... . all / any oil is the same to varying degrees... some are using
> 50w .. put that in the fridge over night and do a fluid test... it no
> longer is fluid...its rock hard.. 0wXX will be better but still is not
> great..
>
> --------
> Ross Aalexander: CH701 driver 912ul 589tt
> It only takes two things to fly, airspeed and money
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=387950#387950
>
>
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>
>
Message 4
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| Subject: | Re: Rotax 912 Preheating |
Barry,
Do you preheat your car? With it's big oil sump, you'll see lots more
water there. Somehow they last for many hundreds of thousands of miles
without (most people) preheating. (If you drive a diesel, this does not
apply due to the higher compression ratios. I preheated my old Benz, even
with its glow plugs, to help it turn over easier.) However, water
in engines all gets boiled off during operation, so the only water you will
see is from what might have condensed inside since last shutdown. I think
you are worried too much about its effects. If it was a serious issue, you
sure would have at least seen a procedure for how to do it in the engine
owner's manual.
That said, I sure agree that it is sure a whole lot easier to start a
pre-heated engine when it is really cold outside!
Gerry
On Thu, Nov 15, 2012 at 7:46 AM, FLYaDIVE <flyadive@gmail.com> wrote:
> Hi Ross:
>
> There is always water in oil. Of course you reduce the quantity by
> flying often.
> An easy way to prove this to yourself is:
> After a flight - Open up your Oil Cap. What do you see coming out? A
> white vapor. That white vapor is water. Now, take a smooth sheet of
> aluminum and hold it in the vapor. What do you see? Water condensing on
> the aluminum.
>
> Part of the normal COMBUSTION process is water -
>
Message 5
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| Subject: | Re: Rotax 912 Preheating |
Gerry:
You did not spend much time thinking through your email.
1 - You did not ask where I live -- - I could live in Florida and never
require pre-heating. I could live in Alaska or North Dakota and have to
pre-heat all winter long.
Did you know that in extreme cold areas such as Alaska and North Dakota, if
the plane is going to sit for a few days and then be flown, they remove the
oil and bring it in a heated area.
2 - The size of the sump (not a sump but an oil pan) on a car is usually
about 4 quarts. The size on Lycoming and Continental is 8 quarts so the
CAR is a much smaller capacity. And capacity has nothing to do with it.
It is the environment and the number of hours flown.
3 - Yes cars do go for hunderds of thousands of miles. The average car is
used EVERYDAY do you fly your plane everyday? Not a good comparison.
4 - DIESEL - Diesel fuel is why diesel engines are pre-heated NOT the
compression ratio. The GLOW PLUGS on a diesel are there to START
COMBUSTION by pre-heating the inside of the cylinder. They are kept
glowing by the combustion process. Diesel fuel GELS at low temperatures, a
gelled fuel is extremely difficult to burn.
Want to learn something - Take a small 3" diameter pan. Put in 1/8" of
diesel fuel. Throw a match into it. What do you thinks will happen?
NOTHING! NOTHING - The match will go out. That should show you how POOR
diesel fuel is as an accelerant.
My Diesel Rabbit had two pre heaters, one in the dipstick and one on the
oil pan. Both raised the temp under the hood enough to heat a Metal
Cased Cartage Oil Filter enough to prevent gelling.
Oh, I live in NJ so I get both hot and cold temps.
5 - You did not comprehend my last post. WATER is also added to the oil
through COMBUSTION. ALL the water is NOT boiled off as you think. Other
wise why is there water vapor (Steam) coming out of your oil cap when
opened.
6 - Yes I am worried about effects of cold starts - After all I have
$18,000 invested in my engine NOT counting the plane, or the people that
fly in it.
7 - Seven as in CRAPS you loose - " If it was a serious issue, you sure
would have at least seen a procedure for how to do it in the engine owner's
manual." You are so willing blindly trust a manual as to not use common
sense and consider who ever wrote and accepted the manual could have missed
writing the section on COLD STARTS!
OR - OR you don't think BUSINESS comes before common sense? Think on how
many planes are built WITHOUT a cowl. How do you preheat an engine without
a cowl? How many engines would NOT be sold if the plane was to be used in
colder areas such as NJ - IF - The manual said: Pre-heat at 32 F and
below.
RTFQS
Barry
On Thu, Nov 15, 2012 at 11:42 AM, Gerry Visel <gcvisel@gmail.com> wrote:
> Barry,
>
> Do you preheat your car? With it's big oil sump, you'll see lots more
> water there. Somehow they last for many hundreds of thousands of miles
> without (most people) preheating. (If you drive a diesel, this does not
> apply due to the higher compression ratios. I preheated my old Benz, even
> with its glow plugs, to help it turn over easier.) However, water
> in engines all gets boiled off during operation, so the only water you will
> see is from what might have condensed inside since last shutdown. I think
> you are worried too much about its effects. If it was a serious issue, you
> sure would have at least seen a procedure for how to do it in the engine
> owner's manual.
>
> That said, I sure agree that it is sure a whole lot easier to start a
> pre-heated engine when it is really cold outside!
>
> Gerry
>
> On Thu, Nov 15, 2012 at 7:46 AM, FLYaDIVE <flyadive@gmail.com> wrote:
>
>> Hi Ross:
>>
>> There is always water in oil. Of course you reduce the quantity by
>> flying often.
>> An easy way to prove this to yourself is:
>> After a flight - Open up your Oil Cap. What do you see coming out? A
>> white vapor. That white vapor is water. Now, take a smooth sheet of
>> aluminum and hold it in the vapor. What do you see? Water condensing on
>> the aluminum.
>>
>> Part of the normal COMBUSTION process is water -
>>
>
> *
>
>
> *
>
>
Message 6
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| Subject: | Re: Rotax 912 Preheating |
Get a life, guy.
On Thu, Nov 15, 2012 at 12:05 PM, FLYaDIVE <flyadive@gmail.com> wrote:
>
> You did not spend much time thinking through your email.
>
Message 7
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| Subject: | Re: Rotax 912 Preheating |
Sorry folks, I didn't know. I've learned my lesson.
Raymond Julian
Kettle River, MN.
"And you know that I could have me a million more friends,
and all I'd have to lose is my point of view." - John Prine
On 11/15/2012 12:34 PM, Gerry Visel wrote:
> Get a life, guy.
>
> On Thu, Nov 15, 2012 at 12:05 PM, FLYaDIVE <flyadive@gmail.com
> <mailto:flyadive@gmail.com>> wrote:
>
>
> You did not spend much time thinking through your email.
>
>
> *
>
>
> *
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