Fuel Tank Venting Question

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Dartman_1

Dartman_1

Dart Man
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I have a stock fuel tank on a 1973 Dodge Dart with a single vent line out the top. How and where do I run the fuel vent line to?

- Stock Filler Tube (no vent line in 73)
- Assume to be a non-vented cap (stock)
- I do not want to run the original charcoal canister (too ugly)
- Prefer not to run to the engine bay, but will if need be
- I do have to run the line to the engine bay, then what?
- I'd like to not have fuel sloshing out of the tank or fuel vapors in my garage

Thanks in advance!
 
run it out anywhere under the car towards the rear.

The 69's loop it up and then back down and under the car right near the filler neck.
 
roccodart440 said:
run it out anywhere under the car towards the rear.

The 69's loop it up and then back down and under the car right near the filler neck.
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??? Misleading, and it will likely siphon

The line coming from the tank area clear up to the front of the engine bay----and which originally interconnected with the carbon can system IS YOUR vent on any car with the evap system, and that means some 70, some or all 71, and all after that. They used a "pressure vacuum" filler cap to relieve pressure "in case."

If you have the 1/4 "up front" line intact, it needs to be "up high" in the engine bay to prevent siphoning. You can hook it to a filter, and or plumb it to the air filter bonnet, or even just leave it open. May have a few "fumes" in a garage

What I would lean towards if you are modifying the system is to construct a replica of the 69/ earlier vent, which is a 1/4" line teed into the filler neck up high in the trunk. Goes up, clear up to the top of the rear quarter panel, then loops down alongside the filler and ends (open) below the grommet. This prevents siphoning
 
The smog/ evap controls changed over the years as did the caps. The early ones had a big can "vapor liquid separator." This function was later moved to a "tank" inside the main tank. Your vent.........the only vent......is the line with the valve in it at left of diagram (overfill limiting valve)

2r2q0ra.jpg
 
You would be surprised to know how much fuel is being reclaimed by that system. Just put a measured quantity of gas out in the summer under shade and see how long it lasts. Some of the constituents of gasoline boil at low temperatures and some at higher but IIRC the highest is about 97*F. Not sure. But the point is the same, gasoline is desperate to escape your tank. And that canister, altho ugly is performing a vital service. If you find it too ugly, you can always move it to somewhere less conspicuous.
 
The vent to valve cover that the fuel bowl vented to with connection to the air filter housing on 1970 California emissions that was standard in 1971 works pretty well too if you don’t mind the extra plumbing under hood.
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Dartman_1 said:
I have a stock fuel tank on a 1973 Dodge Dart with a single vent line out the top. How and where do I run the fuel vent line to?

- Stock Filler Tube (no vent line in 73)
- Assume to be a non-vented cap (stock)
- I do not want to run the original charcoal canister (too ugly)
- Prefer not to run to the engine bay, but will if need be
- I do have to run the line to the engine bay, then what?
- I'd like to not have fuel sloshing out of the tank or fuel vapors in my garage

Thanks in advance!
Click to expand...
I used one of these, works good.
Remote Mount Rollover Vent Valve
Have an extra one I’d sell. Shoot me a pm if interested.
 
67Dart273 said:
I don't think so. No reason you could not modify the 73
Click to expand...

This all depends on where the front vent line ends inside the tank .
Mine is up against the roof of the tank, I ran it up thru the floor of the trunk, up hi and put 2 coils in it and back down thru the trunk floor. No problems ! I also have the stock fill tube vent on mine too---------
 
^^Well yeah LOL I intended to mean that you duplicated the 69 style. The reason the line comes up high and then goes down is to break any siphon.

I also agree that retaining the evap system "would be good" IF they could be maintained intact and in safe condition. But with lack of new parts and rust/ corrosion, whatever else 40 years ago, this might not be the case. "I'm about to find out" LOL if the snow ever melts, on the 74 Scamp. It has a locking gas cap, and I'm sure IT IS THE WRONG ONE

img_1813cs-jpg.jpg
 
Without the mostly sealed stock carburetor, the stock vapor collection system won't do much anyways. You won't find any aftermarket carbs that have the carb. vents configured the way the stock ones were.
 
67Dart273 said:
69/ earlier style vent

View attachment 1715298396
Click to expand...
The filler tube vent on my '64 looks like what is pictured, but I have no adjacent holes in the trunk floor to route a hose through. I believe I will drill a hole just behind the wheel tub and run a hose through there.
The vent in the filler tube faces forward at about 10:00 if you look at it from the fill side.
Should I loop once around the filler tube before dropping down or just go over the top toward the back of the car and down?
 
The later ones go through the trunk rubber. The key thing is to "upside down U" it up about as high as you can up towards/ against the top of the rear fender. That and the air pocket in the filler tube is what "breaks" any siphon
 
67Dart273 said:
The later ones go through the trunk rubber. The key thing is to "upside down U" it up about as high as you can up towards/ against the top of the rear fender. That and the air pocket in the filler tube is what "breaks" any siphon
Click to expand...
That's what I thought. Thanks....again!
 
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