RE: Overheating '67

[Eric Helton <stranger@cybcon.com>]

In response to the below question...

>        The theory is that when you are relying on the pump to SUCK the
gas
>        from the tank that you can only such so hard before the gas
>        vaporizeds and you are sucking vapor. Now suddenly the only
thing
>        coming out of the pump is vapor and this doesn't sit nicely in
the
>        carb float bowl anymore.
>
>        >>>>Okay, I definitely understand the principle (and big kudos
to
>you, as you're the first in my relatively meager 16 years of working on
cars
>that made an intelligent response to my dad's prejudices); but, how
would it
>vapourise the fuel by sucking on it?  Wouldn't that require *some* air
leak
>*s–‌W]*?  I really do want to know, because a *lot* of people
believe in
>vapour lock, and while I've never (with the help of my dad) 'had'
vapour
>lock, my dad *is* human.



Matter is matter and all of it follows the same laws regardless of
whether it is
a liquid, gas, or solid state at terran pressures and temperatures.  The
state of
the matter is basically (though not limited to) a function of pressure
and
temperature.  The freon or R12 or whatever refrigerant they use now in
your
refrigerator or air conditioner is a good example of this.  For the most
part, after
the liquid refrigerant runs through the heat exchanger at the back of
the refrigerator,
it is expanded through a throttle.  The pressure on the upward side is
high, where the
refrigerant is a liquid, and the downstream side is low pressure and a
gas.  No air
is introduced into the system, but the refrigerant has changed state
only due to
the change in pressure.  The same mechanism takes place on the other
side in
reverse in compressing the warmer refrigerant (after it removes heat
from inside
the refrigerator) to a liquid and cooling it down.

I have no experience with vapor lock in cars, but I can see how it could
potentially
happen by a combination of low pressure (due to a restricted gas tank
drain and
a fuel pump 'sucking' on the other end of the hose) and temperature.

I see now that someone else has responded.  I hope I'm not beating a
dead horse...


Sincerely,

Eric Helton

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