Howell Fuel Return Line in Vent Line

T

Tom Katzenberger

Well-known member
Jun 26, 2019
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I am installing a Howell EFI. Has anyone had any problem with returning the fuel via the vent line in lieu of putting a hole in the fill tube?
Are there any opinions of one method vs. the other method?

Thanks,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D.
 
Returning fuel into the vent line can work, however there will be time when
that will back fire.
Drill a hole and epoxy a brass fitting on the filler tube.

> I am installing a Howell EFI. Has anyone had any problem with returning
> the fuel via the vent line in lieu of putting a hole in the fill tube?
> Are there any opinions of one method vs. the other method?
>
> Thanks,
> Tom K.
> --
> Tom & Oki Katzenberger,
> Kingsville, Maryland,
> 1977 23' Birchaven, 455 C.I.D.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
As Jim stated, that is the way I did it to help with vapor lock.

> Returning fuel into the vent line can work, however there will be time when
> that will back fire.
> Drill a hole and epoxy a brass fitting on the filler tube.
>

>
> > I am installing a Howell EFI. Has anyone had any problem with returning
> > the fuel via the vent line in lieu of putting a hole in the fill tube?
> > Are there any opinions of one method vs. the other method?
> >
> > Thanks,
> > Tom K.
> > --
> > Tom & Oki Katzenberger,
> > Kingsville, Maryland,
> > 1977 23' Birchaven, 455 C.I.D.
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> >
>
>
> --
> Jim Kanomata ASE
> Applied/GMC, Newark,CA
> jimk
> http://www.gmcrvparts.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Scott Campbell
Jack of All, Master of None!
President AMCA River Valley Chapter
1980 FXEF, 1997 XL, 2000 FLHT, 2014 FLD
1982 Chevy G20
1973 GMC Glacier Motorhome
 
Using the vent line as a fuel return line is akin to having a wet vent in a residential plumbing waste line. Most codes allow it but require the pipe
size be increased. Sewer gases are a lot "friendlier" than volatile liquid gas and vapor, and plumbing pipe is far larger.

What's the advantage of not returning the fuel to the filler neck?

Richard
--
'77 Birchaven TZE...777;
'76 Palm Beach under construction;
‘76 Edgemonte waiting its turn
 
Tom,

I answered this too soon in the post below.

If by vent line, you mean the fill vent that runs up to the fill neck, that would have to be good. Once the fill cap is on, that line is doing
nothing until the cap is opened again. If you do the High T Mod that I and others have found successful, you can even pick which tank you want the
returning fuel to go to.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
I absolutely plan on the High Tee mod.

I have the tanks out and am installing stainless lines from the pump to the TBI and then back to the tanks some how.

I am trying to figure out what is the best way to return the fuel to the tanks. Not as much interested in the easiest or cheapest. I can Tig weld in
the tank or tube as the system has been completely drained washed, zink coated and coated with master coat.

The coach is in the air and all is exposed.

Thank you all for your thoughts, I just haven't settled on which direction to go. I do like Kens idea of dumping it back in the AUX tank. I am worried
about the long term results with JB weld in the fill tube.

Thanks again,
Tom K
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D.
 
On a somewhat similar note...

I have an EFI pump with a check valve for each tank and no longer use the diverter. I'm thinking about doing the 'High T mod' by plugging the hard
line vent T going to the Aux tank and splicing in a 3/8" barricade rubber line to the Aux tank vent line, fastened to the hard line going forward, and
then teed into the 1/2" vent line about half way up to its connection to the filler vent.

Since I presently have the EFI return going to the fill tube, and understand that with that arrangement return fuel(mostly) goes to the Main tank.....
Is there any advantage to installing the diverter such that it returns fuel to either the Main tank (via filler tube) or to the Aux tank via the new
vent line based on the position of the dash selector switch so that return fuel goes to the tank that it's coming from?

If not, does it make sense to move the return to the new Aux tank vent line?
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015.
 
Tom,
I'm sure your aware that when welding on a gas tank empty, you need to fill
with water or purge the gas vapors as it will burst.

On Thu, Sep 9, 2021 at 12:54 PM Bill Van Vlack
wrote:

> On a somewhat similar note...
>
> I have an EFI pump with a check valve for each tank and no longer use the
> diverter. I'm thinking about doing the 'High T mod' by plugging the hard
> line vent T going to the Aux tank and splicing in a 3/8" barricade rubber
> line to the Aux tank vent line, fastened to the hard line going forward, and
> then teed into the 1/2" vent line about half way up to its connection to
> the filler vent.
>
> Since I presently have the EFI return going to the fill tube, and
> understand that with that arrangement return fuel(mostly) goes to the Main
> tank.....
> Is there any advantage to installing the diverter such that it returns
> fuel to either the Main tank (via filler tube) or to the Aux tank via the
> new
> vent line based on the position of the dash selector switch so that return
> fuel goes to the tank that it's coming from?
>
> If not, does it make sense to move the return to the new Aux tank vent
> line?
> --
> Bill Van Vlack
> '76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath,
> Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o
> mid
> November 2015.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
Jim,

Yes, I fill them with water and leave a torch burning as the water drains out. They are spotless inside and out.

That being said, I must tell you I sincerely appreciate you stepping in and backing me up with such a possibly dangerous situation.

Thank you for not letting step in front of the train.

Sincerely,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D.
 
Returning the fuel to the tanks via the vent lines can cause a "burp" of fuel when you start refilling due to liquid fuel in the vent lines.

Doing the High-T mod to the vent lines may help, but you need to be sure there is no dips in the vent lines to hold liquid fuel.

Mine is returned to the filler line and the fuel tends to return to the Main (rear) tank. I don't think of them as Main and Aux, more like just front
and rear tanks (there are no labels on my fuel switch). Once you get down to 5/8 tank and less, more fuel tends to end up in the Aux tank, especially
when going down a long hill. I tend to run on the front tank as much as the rear.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
I decided to weld a stainless nipple in the left side of the front (Aux) tank. I hope this is a good solution as there appear to be several good
solutions out there. I most liked the fill tube option, but did not feel comfortable with relying on the JB Weld joint. I thought this may be best
because it is easy to inspect for leaks or weld failure. I wanted it in the top but just don't have the clearance and I would not be able to inspect
weld or metal fatigue.

Has anyone had any back pressure issues with returning the fuel in the side?

Take care,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D.
 
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