Trunk Vent Tube Question

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70 Buster 340

70 Buster 340

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What year Dusters/Demons/Sports have these 'elaborate' vent tube contraptions?
How/what/where do all these lines connect? Tank vent, bowl vent, charcoal canister? ... and then two more. What's inside, anyone look?
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Your original gas tank had 4 vent tubes exiting the drivers side of the tank. From there they connected to a tube in the trunk. There was a hard line running from the fifth tube connection from the trunk that sucked the vapor from the tube and ran to the engine bay going back to the motor thus saving the planet from harmful gas vapor and for ever causing confusion over what gas cap to buy For your filler tube.
 
one vent from the neck to under the rear of the car seems sufficient unless you re doing a points resto
 
Wow, that Allpar article tells all. What a crazy set-up in a crazy time of saving the planet from 'vapors'.

My 70 is a bracket racer so that 'thing' in the trunk is coming out. Fuel cell will get a tipover valve and a simple vent through the trunk floor.

Thanks for your help on this.
 
I know this is an old thread but I have a 71 that has the 4 vent tank, when I replaced the tank and went to hook up all the vent lines, most of the hoses were dry rotted and basically useless. The evap containment system is out of the car and the vent from the carb bowls stripped out of it as well. How should I handle the vents in the tank? From the article, there's 1 going to each corner, should I just put new hose and vent them out the side or the bottom? It's not a restoration, so I'm not worried about looks, just keeping the engine and fuel system running.
 
I think you'll have to cap off 3 of the 4 and run a hose off the 4th tank vent.
Would work to connect that 4th line to the hard line that goes back to the bowl vent.
But ... since that hard line was removed you'll have to run a hose that is higher than the tank. Vent could go to the fill tube but you'll have to drill a hole and add a fitting to connect the 4th hose to. You could run a hose with a loop high up in the trunk and then put a tip over vent through the trunk floor. Has to vent outside the car no matter how unless you vent to the carb bowl.

I made a change on my set up, the fuel cell vent goes to a rubber hose with a loop high up and the tip over vent valve is now mounted where the gas cap was. The fill tube was removed for now because the cell is not the quick fill NASCAR type. I could convert to that and fill the cell from the original gas cap which might be kinda handy.
Sounds confusing but if I get some pictures it's pretty simple.
 
That "contraption" is a vapor separator and was used the first few years of the evap control system. Somwhere around 73-ish they got rid of the "contraption" and went to a separator in the tank. You need a vent and that system incorporated the vent

I've said this many times----in my opinion, if you cannot keep the factory vent tubes and leave the engine bay tube open for a vent, then consider modifying your filler neck to mimick the 69/ earlier system. Look it up in the FSM. You can download them, free at MyMopar

The 69-ish and earlier system. Some 70's had evap some did not. I think someone here claimed some 71's also had no evap. This all started in...............CA

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I'm pretty sure 71 had evac separation system, the original tank was a 4 vent version so it most likely was this type of system. In mine, the car was gutted from a slant 6 and then a 360 dropped in, and it wasn't done well, they also left off the kickdown/TPV linkage when they did the swap and a bunch of other highly irritating issues I've been chasing my tail with. With regard to this, would capping all 4 off and using a truly vented gas cap work?
 
Dave Haertel said:
I'm pretty sure 71 had evac separation system, the original tank was a 4 vent version so it most likely was this type of system. In mine, the car was gutted from a slant 6 and then a 360 dropped in, and it wasn't done well, they also left off the kickdown/TPV linkage when they did the swap and a bunch of other highly irritating issues I've been chasing my tail with. With regard to this, would capping all 4 off and using a truly vented gas cap work?[/QUOTE]

Probably ... if you don't 'fill'er up to the rim'. The A body gas cap is definitely high enough above the fuel level.
I have seen where bad venting can collapse a gas tank ... sucked it like a soda can in as the fuel sucked out and no air could get in.
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