1970 Duster gas tank venting

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Bills70

Bills70

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let me start but saying hi. this is my first mopar and I did not take this car apart. I am installing a new gas tank and I see that it has four vent tubes. can I just plug them or do they need to be hooked up? if I hook them up, where and what do they hook to? I assume it is a canister? a picture if possible would be great!
 
Welcome to the A-body fuel systems. I just completed my new tank install last night! I replaced the 4 vent tank with a single vent tank. But sounds like you have a new 4 vent tank ready to install. when you look in the trunk there should be a galvanized steel tube running upright but slightly leaning near your gas tank fill tube. That's where those 4 vent lines ultimately hook up to. But when you're under the car those 4 lines will hook up to 4 lines which go to that tube to breathe.......if that's all been removed though and you've got the 4 vent tank? Well, you'll just have to look inside the trunk. If there's no "pipe" next to the fill tube then it's the wrong tank for the car. If you do then a simple plug and play! Easy search results below....

Weird pipe in the trunk

Question about gas tank vents 4 vs. 1
 
Alaskan_TA said:
........You do not have to hook it up,.........
Click to expand...

This is NOT EXACTLY TRUE. If you don't hook it up you will NOT have a tank vent. That is, if the system was originally part of the car.

OP........if you have this system originally, there should be a big vapor separator in the trunk. If NOT they you should have a vent tube coming out "high" on the filler tube through the trunk. YOU NEED A VENT one way or t' other

This is what the "up through" 69 and not evap equipped 70 vent system looks like, and is what you want to duplicate if you do not want to hook up the evap stuff

242yckm.jpg
 
"That is, if the system was originally part of the car."

That is why I asked if it had N95. ;-)
 
The 71 (and on some 70 vehciles) with the 4 tubes sticking out of the side is just a crappy inferior venting design, and a pain to hook up. Also the canister in the trunk can be unsafe if fumes escape it and get into the trunk. There's a reason they only used those for a year or so.

Your best bet is to return that tank and get a 72+ tank. Superior venting system, much easier to hook up, and very easy to splice into an existing vent line.
 
CowBoyRoy81 said:
Welcome to the A-body fuel systems. I just completed my new tank install last night! I replaced the 4 vent tank with a single vent tank. But sounds like you have a new 4 vent tank ready to install. when you look in the trunk there should be a galvanized steel tube running upright but slightly leaning near your gas tank fill tube. That's where those 4 vent lines ultimately hook up to. But when you're under the car those 4 lines will hook up to 4 lines which go to that tube to breathe.......if that's all been removed though and you've got the 4 vent tank? Well, you'll just have to look inside the trunk. If there's no "pipe" next to the fill tube then it's the wrong tank for the car. If you do then a simple plug and play! Easy search results below....

Weird pipe in the trunk

Question about gas tank vents 4 vs. 1
Click to expand...
my fill tube does have a vent line on it, but it appears that all the other stuff has been removed from car (breather and lines), some one before me was going to make this Duster into a race car and had removed gas tank and cut the spare tire trunk pan out, which I have replaced. buy your response it sounds like I should have bought a different Tank? or can I make this one work? there is no four tubes or breather tank anywhere that I can see! here are some pics

DSC00204.JPG


DSC00206.JPG


DSC00205.JPG
 
kiss said:
The 71 (and on some 70 vehciles) with the 4 tubes sticking out of the side is just a crappy inferior venting design, and a pain to hook up. Also the canister in the trunk can be unsafe if fumes escape it and get into the trunk. There's a reason they only used those for a year or so.

Your best bet is to return that tank and get a 72+ tank. Superior venting system, much easier to hook up, and very easy to splice into an existing vent line.
Click to expand...
I wish I had asked this before I went and ordered the tank I got. looks like I will be calling Classic Ind. now am I going to need a different gas cap also and what about fill tube?
 
Stay with your current fill tube and cap. You have the 70 and earlier venting system. There are stock replacement tanks readily available.

Also the other tube wasn't removed from the car, it wasn't there, you just bought the wrong tank is all. It happens. Some 70s cars used the tank you bought, but not yours.
 
You can just cap the 4 tank nipples since your filler tube has the correct vent for your original application.
 
67Dart273 said:
This is NOT EXACTLY TRUE. If you don't hook it up you will NOT have a tank vent. That is, if the system was originally part of the car.

OP........if you have this system originally, there should be a big vapor separator in the trunk. If NOT they you should have a vent tube coming out "high" on the filler tube through the trunk. YOU NEED A VENT one way or t' other

This is what the "up through" 69 and not evap equipped 70 vent system looks like, and is what you want to duplicate if you do not want to hook up the evap stuff

View attachment 1715073375
Click to expand...
are you saying that I can just plug everything except for the line on the fill tube and just run that thru rubber gasket under car?
 
Alaskan_TA said:
You can just cap the 4 tank nipples since your filler tube has the correct vent for your original application.
Click to expand...
so I just run the vent line thru rubber gasket and under the car? also, should I run the line away from gasket to keep fumes from coming in car?
 
your filler neck already has the vent on it
your stock tank has no additional vents
 
Alaskan_TA said:
You can just cap the 4 tank nipples since your filler tube has the correct vent for your original application.
Click to expand...
I would only do this as a very last resort. I've seen those vent tubes crack or even break-out from the side of the tank on 2 different vehicles. This causes gas leak/seepage/fumes. Royal pain to deal with.
 
kiss said:
Stay with your current fill tube and cap. You have the 70 and earlier venting system. There are stock replacement tanks readily available.

Also the other tube wasn't removed from the car, it wasn't there, you just bought the wrong tank is all. It happens. Some 70s cars used the tank you bought, but not yours.
Click to expand...
I am not sure what really came on this car. what you see in the pics are what came with it when I got it and as for the cap the car did not have one so I believe I bought one for a vented system. what tank should I buy from Classic Ind.? the one for 71-76 16 gal.with one vent pipe in front or 68-70 18 gal. with no vent pipe?
 
Bills70 said:
I am not sure what really came on this car. what you see in the pics are what came with it when I got it and as for the cap the car did not have one so I believe I bought one for a vented system. what tank should I buy from Classic Ind.? the one for 71-76 16 gal.with one vent pipe in front or 68-70 18 gal. with no vent pipe?
Click to expand...
The one with no vent pipe if you're going to use that filler neck
 
Yes. You are ok to plug the 4 vent lines from the tank. That filler tube will vent. Just ensure there's no cracks in that little line. Plum it down through the odd shaped rubber gasket in trunk floor. Don't over think he venting. It's only to allow suction from carb/fuel pump draw and heat/cold expansion and contraction.
 
Bills70 said:
my fill tube does have a vent line on it, but it appears that all the other stuff has been removed from car (breather and lines), some one before me was going to make this Duster into a race car and had removed gas tank and cut the spare tire trunk pan out, which I have replaced. buy your response it sounds like I should have bought a different Tank? or can I make this one work? there is no four tubes or breather tank anywhere that I can see! here are some pics
Click to expand...

Your car either never had the evap system or else someone added that vent/ filler. THAT IS what you want for a vent. With that, you can simply cap off the nipples at the tank

Also, if you ever decide to add a vapor return system, you could use one of those nipple. If you go with EFI, you could conceivably parallel 3 or all 4 to get enough volume, and use them for your EFI regulator return

The "deal is" having that system in '70 seems to be a CA state issue. My '70 "sixpack" car was originally sold in OR and never had it. Try to tell THAT to the CHP
 
Bills70 said:
my fill tube does have a vent line on it, but it appears that all the other stuff has been removed from car (breather and lines), some one before me was going to make this Duster into a race car and had removed gas tank and cut the spare tire trunk pan out, which I have replaced. buy your response it sounds like I should have bought a different Tank? or can I make this one work? there is no four tubes or breather tank anywhere that I can see! here are some pics

View attachment 1715073389

View attachment 1715073390

View attachment 1715073391
Click to expand...
That fill pipe will work with any tank. The tank needs no additional venting, so you can plug any additional vent lines on the tank itself. Or get a non-vented tank. Also use a non-vented gas cap. And attach a hose to the end of the metal line on your fill pipe and run it to outside/under the car.
 
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