Gas filler neck vent

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acmack
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Gas filler neck vent

Post by acmack » Fri Jan 03, 2014 2:39 am

I have 2 GPA gas filler assys. One has the vent tube routed to the outside air and the other back into the gas tank?

Are the differences due to an early and late style?

David
GPA 9545
GPA 10568
1965 Apollo BP capsule A36
1960 Gemini BP capsule MSC 312

acmack
Posts: 133
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Re: Gas filler neck vent

Post by acmack » Mon Jan 20, 2014 1:00 am

I guess some photos would help?

Notice how one of the GPA filler neck vents pass through the wall of the filler allowing it to vent to the outside and the other keeps the tube inside of the structure venting into the tank.


Image

Image

Is one an early model and one a later? If so which is which?

David
GPA 9545
GPA 10568
1965 Apollo BP capsule A36
1960 Gemini BP capsule MSC 312

bobassel
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Re: Gas filler neck vent

Post by bobassel » Tue Jan 21, 2014 10:44 am

Hi David,
In my opinion the filler neck with the tube inside is the normal version.
It is possible that the one with the outside tube is the early model, but I think this is not
a good idea because it is hard to keep the water out with a rubber seal on the rear deck.
Maybe David Welch can tell you if his early one had the same "early" model?
It is for us all interesting to know if this is early or late lol
Bob
Ford GPA 12350, april 4th 1943
Author of GPA book,
Willys MD M38A1, A13817 1952

acmack
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Re: Gas filler neck vent

Post by acmack » Tue Jan 21, 2014 3:21 pm

I can see how the internal tube design helps in rapid gas filling but not in relieving gas pressure expansion developing in the tank, for example, on a hot day. The external vent design would accomplish both.
I agree though that if the rear deck took on a breaking wave that water might wash backwards into the gas tank through the external tube design. But then again if the filler cap and tank were properly sealed sea water could not push it's way in through the external vent tube in a full bolus anymore than you can rapidly fill a gas tank without a vent tube.

David
Last edited by acmack on Tue Jan 21, 2014 4:28 pm, edited 1 time in total.
GPA 9545
GPA 10568
1965 Apollo BP capsule A36
1960 Gemini BP capsule MSC 312

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GlennV
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Re: Gas filler neck vent

Post by GlennV » Tue Jan 21, 2014 3:36 pm

I would think that the external vent design would allow gas vapors into the hull, which could cause an explosion hazard.

Therefore to me, this would be an 'early' design ....

Fyi, i have the internal tube design in my GPA.

Kind regards,
Glenn
Ford GPA - SN 5892 - DOD Jan 14 1943
Willys MB - SN 456307 - DOD July 30 1945

acmack
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Re: Gas filler neck vent

Post by acmack » Tue Jan 21, 2014 4:31 pm

The open tube design I posted vents above the rear deck and to the rear of the cabin. Unless you are driving backwards or the windspeed is from your stern at a greater rate than your forward speed venting is moved away or straight up into the atmosphere.

Where does gas tank pressure vent from in an internal tube design?

I would not think from the tank fittings as that would fill the rear bilge with gas fumes where the batteries are located!

In modern car designs the gas tank vents to outside air but fumes pass through a gas vapor filter/trap first.

David
GPA 9545
GPA 10568
1965 Apollo BP capsule A36
1960 Gemini BP capsule MSC 312

acmack
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Joined: Wed Feb 08, 2006 1:31 am
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Re: Gas filler neck vent

Post by acmack » Mon Apr 07, 2014 1:56 am

So, no one else has seen or has an external vent type filler neck?

David
GPA 9545
GPA 10568
1965 Apollo BP capsule A36
1960 Gemini BP capsule MSC 312

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Cees
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Re: Gas filler neck vent

Post by Cees » Fri Jan 30, 2015 8:51 pm

David,
It looks like a fillerneck from a Dodge commandcar WC56/57
Cees
1941 Ford GP,
1943 Ford GPA #6849,
1943 Ford GPA # 7741,
1943 Harley WLC,
Dodge WC57,
1942 BMW R75,
1942 KS750,
1944 VW 166,
1940 Hanomag 20b,

http://www.filmprops.nl/produkten/fordgpa.htm

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Cees
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Re: Gas filler neck vent

Post by Cees » Sat Jan 31, 2015 1:27 pm

Image

It looks they cut the tube, that is why the rubber hose is long.
1941 Ford GP,
1943 Ford GPA #6849,
1943 Ford GPA # 7741,
1943 Harley WLC,
Dodge WC57,
1942 BMW R75,
1942 KS750,
1944 VW 166,
1940 Hanomag 20b,

http://www.filmprops.nl/produkten/fordgpa.htm

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