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From: jeq@ihwpt.UUCP (j quist)
Newsgroups: net.auto.tech
Subject: Re: Vapor Lock
Message-ID: <582@ihwpt.UUCP>
Date: Sat, 23-Nov-85 12:25:09 EST
Article-I.D.: ihwpt.582
Posted: Sat Nov 23 12:25:09 1985
Date-Received: Sun, 24-Nov-85 07:28:20 EST
References: <2922@vax4.fluke.UUCP>
Distribution: net
Organization: AT&T Bell Laboratories
Lines: 29

> Im sorry Randle but there is no such thing as "Vapor Lock" in today's
> automobiles.  Vapor lock originated with the gravity feed fuel systems
> of the Model T era because what would happen is the gas would get
> close to boiling and bubbles would form in the fuel lines and try to
> go up as the fuel is trying to go down.  The result was a stalemate or
> what is known as vapor lock.
> 
> Today's fuel pumps push fuel at a pressure of 7-10 psi and no bubble
> could ever have any effect on it.  

I've got a '72 MGB that would disagree. 
One can argue that since the fuel system of
a '72 MGB isn't much different from a '58 MGA,
the B doesn't classify as one of today's automobiles...

Anyhow, I've seen vapor lock on relatively new cars.
The conditions:  Hot day, clogged fuel filter,
and a quarter tank of gasohol.  With a full tank,
the problem would partly disappear (higher fuel pressure
at the tank).  Of course, a good mechanic would spot
the clogged filter in short order, and not mumble
mysticisms about vapor lock. :')

Jonathan E. Quist
Lachman Associates Inc.,
at AT&T Bell Laboratories
ihnp4!ihwpt!jeq

(Does anybody else out there dislike alcohol in your gas?)