Vapor lock feedback

For any pump to pull through and push is not the issue.
When gasoline is drawn through the filter, there is a differential pressure
created that invites vapor pockets.
To avoid that to some degree, we use high capacity filter cartridges that
has lower pressure drop.
Larger capacity has 3-4 times more media area so the particulets are spread
out on the media to where the restriction climbs up at a much slower rate.

> I have been over this on the net, and done presentations at several rallies
> on the West Coast about what many here describe as vapor lock. Don't know
> if that is an exact term or not, but, for those of you out there in
> GMCVILLE who are having issues with driveability of their coaches on days
> warmer than 85 degrees or so, I will try to aproach how to deal with it,
> not what causes it.
> 1. Get rid of your winter fuel.
> 2. Run with your tanks as full as possible.
> 3. Drive early in the day when it is cooler.
> 4. Keep your filters clean, carry spares.
> 5. Install an inline electric fuel pump after the selector valve.
> 6. Use ethanol free fuel if possible.
> Most of the time, this is all that is needed. The problem is NOT WITH YOUR
> COACH. IT IS WITH THE FUEL. So, fixing the coach is NOT going to make your
> problems go away totally.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>

>

> > I second the little Qjet filter only takes a little shmoots that will
> cause this same issue. It may not be your issue but they are cheap and I
> > keep a few in the glove box and replace from time to time. Even though my
> fuel system has been redone ie. tanks sealed,fuel lines replaced etc . I
> > too have aux carter and hit it when she starts to stumble seems to help
> but it has done it to me even with the aux pump on. Has anyone had any luck
> > with the 3 port/return line mechanical pump the Toros had on them to
> remedy VL ?
>
>
> We ended up also installing an inline metal filter between the metal line
> and fuel pump inlet to help keep stuff from getting to the pump, just in
> case. Super easy to change out if needed, and is a little larger than the
> one at the carb. For what it's worth.
> --
> Chris S. -
> 77 Kingsley, 3.70 FD, mostly OEM -
> S.E. Michigan
>
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
> > what coating, mine is steel.
> >
> >
> > so maybe it did!
> >
> > ________________________________
> > From: Gmclist on behalf of David H.Jarvis
> > Sent: Monday, June 5, 2017 11:59:40 AM
> > To: gmclist
> > Subject: Re: [GMCnet] Vapor lock feedback
> >
> > Has anyone had a problem with the ethanol gas dissolving the coating inside the gas tank?
> >
> > _______________________________________________
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>
> He said he had the fuel tanks cleaned and COATED. That would not be on the outside.


FYI our tanks were refurbished by Gas Tank Renu, and they coated both the inside and outside. Never had a problem with their work, on another vehicle
nor this one so far. But for peace of mind we have a fuel filter just before the pump in case something is sucked through up to that point.
--
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan
 
What I did to elemenate vapor lock in my carbureted engine.block the intake crossover. Coated the fuel tank exterior, heat shields on exhaust pipe,
remove mechanics pump and install 2 carter electric outside frame rail, insulate new metal lines from pumps to carburetor running from rear of engine
rather then the front. Also no winter gas in hot weather.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
Curious, was all that required? Or did the crossover blocking actually
solve it 100%?

> What I did to elemenate vapor lock in my carbureted engine.block the intake crossover. Coated the fuel tank exterior, heat shields on exhaust pipe,
> remove mechanics pump and install 2 carter electric outside frame rail, insulate new metal lines from pumps to carburetor running from rear of engine
> rather then the front. Also no winter gas in hot weather.
 
Any thoughts about using one of the large Marine fuel/water separator filters back near the gas tanks?
My father used one on his Olds with 350 diesel, to clean up 'filthy' Mexican diesel on the South Texas border. Price was govt controlled $.11 a
gallon. (Early 1980's).
Tom, MS II
--
1975 GMC Avion
KA4CSG
 
> Curious, was all that required? Or did the crossover blocking actually
> solve it 100%?

For us, the crossover blocking did not help. However, we went from the iron to aluminum manifold (and block off kit) all at the same time. And we
have the same vapor lock going on as before we made this change. For what it's worth.
--
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan
 
Nope every little bit helps to elemenate vapor lock in my opinion.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
Thanks for the feedback. Our experience was exactly the opposite: our
'vapor lock' would not let us run more than a few miles at a time.
Filled the crossovers (we actually had the cracks) and our 'vapor lock'
was solved 100%. For what it's worth.

>> Curious, was all that required? Or did the crossover blocking actually
>> solve it 100%?
>
> For us, the crossover blocking did not help. However, we went from the iron to aluminum manifold (and block off kit) all at the same time. And we
> have the same vapor lock going on as before we made this change. For what it's worth.
 
That is why I am reluctant to call all these driveability issues "vapor
lock". Very few of them, truly are actual vapor locking. They just mimic
the symptoms. Some are mechanical, like cracked manifolds, vacuum leaks,
cracked fuel lines, loose fittings, carb base plate warping, and on and on.
Some are engine temperature related, some are environmental, like in
outside temperature, some are FUEL RELATED, some are operator caused. No
single answer is going to solve all the causes. Carefull investigation and
diagnosis is required here to MINIMIZE the problem, or in this case,
problems.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> Thanks for the feedback. Our experience was exactly the opposite: our
> 'vapor lock' would not let us run more than a few miles at a time. Filled
> the crossovers (we actually had the cracks) and our 'vapor lock' was solved
> 100%. For what it's worth.
>

>

>>
>>> Curious, was all that required? Or did the crossover blocking actually
>>> solve it 100%?
>>>
>>
>> For us, the crossover blocking did not help. However, we went from the
>> iron to aluminum manifold (and block off kit) all at the same time. And we
>> have the same vapor lock going on as before we made this change. For
>> what it's worth.
>>
>
>
>
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