[AT] oil change

William Powell william.neff.powell at comcast.net
Fri Dec 7 14:46:27 PST 2007


Larry,

No, that's not what I think I said.... At this point I can't be sure of
anything... Sorry for the bad English, writing was never my strong
subject....

Here's what I found and I think they make a different point about energy
consumption causing icing due to air pressure changes, not gasoline crossing
a phase barrier...:  
http://www.flycorvair.com/carbice.html




"Ice can form on warm days. Anytime a gas expands from high pressure to  low
it will consume energy from its environment. In this case, the gas is the
air the engine is consuming and the pressure drop is from ambient to
manifold  pressure, about 30"map to 12"map. The energy it consumes is any
form of     available heat. Most of the heat comes out of the air. This
temperature drop  is instantaneous and can easily be more than 40F. Shoot a
thermometer with a  CO2 extinguisher and learn."

But, in section 5 they kind of make the point I was trying to make....

    "Misted fuel is still a liquid, not a vapor. 100LL under these 
    conditions remains a mist until reaching the combustion chamber.
Contrast 
    this with auto fuel, which by design will vaporize readily under these 
    circumstances. It is a fact of physics that when the fuel changes from a

    liquid mist to a gaseous vapor, it takes further heat from the
surrounding 
    air. This is the cooling one feels when gas evaporates off the skin.
This 
    additional temperature drop can produce icing when the same engine under

    identical circumstances would not ice with 100LL." 





I guess I did not really know what carb icing was, I just noticed the frost
on my WD when I plow snow, looks like it can effect the inside of the carb
and be quite a problem on a plane.... 


Regards,

Will 

-----Original Message-----
From: at-bounces at lists.antique-tractor.com
[mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Larry D Goss
Sent: Friday, December 07, 2007 5:11 PM
To: Antique tractor email discussion group
Subject: Re: [AT] oil change

Carburetor icing is frozen gasoline?  Now that, I want to see.  That may not
be what you intended to say, but that's what I think I see.

Larry

----- Original Message -----
From: <william.neff.powell at comcast.net>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Friday, December 07, 2007 12:32 PM
Subject: Re: [AT] oil change


> >From little chemistry I had in college I always thought that the frost on

> >the carb was from the vaporization of the gasoline. I remember that when 
> >a liquid crosses the phase barrier to a gas it takes a lot of energy to 
> >cross... So, as with freon, when gas evaporates, heat energy is taken 
> >during the conversion which cools off the carb.
>
> Also, many old tractors do not have heat risers, so, the dense cold air 
> coming in does not  help the gas evaporate, so, you stall out unless you 
> force more fuel in by putting on the choke. Eventually the manifolds heat 
> up and your fine, slow speeds, low wind.. For an old tractor lover this is

> a minor inconvenience, but probably unacceptable for most auto drivers 
> zooming down the road at 60 cooling off their manifolds.
>
> As far as the injectors, aren't most of them spraying in right at the 
> manifold near the head? That area probably heats up fast.
>
>
>
>
>
> -------------- Original message ----------------------
> From: Ralph Goff <alfg at sasktel.net>
>>
>> ----- Original Message ----- 
>> From: "Larry D Goss" <rlgoss at evansville.net>
>> To: "Antique tractor email discussion group" 
>> <at at lists.antique-tractor.com>
>> Sent: Friday, December 07, 2007 11:40 AM
>> Subject: Re: [AT] oil change
>>
>>
>> > Question of the day -- does carburetor icing occur on fuel injected
>> > engines?
>> > :-)
>>
>> Hi Larry
>> If icing does occur in fuel injected engine I have never noticed it. My 
>> 97
>> Blazer starts and runs smoother than any carbureted engine I have ever
>> known. No stumbling or hesitation, no black smoke and stalling. I don't 
>> know
>> how they do it but it works.
>>
>> Ralph in Sask.
>>
>> _______________________________________________
>> AT mailing list
>> http://www.antique-tractor.com/mailman/listinfo/at
>
> _______________________________________________
> AT mailing list
> http://www.antique-tractor.com/mailman/listinfo/at
> 


_______________________________________________
AT mailing list
http://www.antique-tractor.com/mailman/listinfo/at




More information about the AT mailing list