Snake
Mopar Nut
I just got my gas cap from Rock Auto ,thanks to RRR who turned me on to it.Is the cap vented,if so can i now plug off the line that went to the carbon cannister.
Is this gas cap vented
- Thread starter Snake
- Start date
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nm9stheham
Well-Known Member
With the small holes in the center, it does indeed look like it. BTW, I have had a cheapo one that looked like yours stick closed, and the stock mechanical pump sucked in the tank.... So if that is not a Stant brand cap, I would not use it.
Snake
Mopar Nut
It says it is a Stant cap.
You could use a filler neck out of a 68-69 that is vented and not worry about the cap?
67Dart273
Well-Known Member
Look up the part no. A 70 / later "pressure vacuum" cap is not technically vented. It is pressure release. I'm against using a vented cap on these girls. I believe, that at some point, you will have fuel all over the fender.
One option is as above, duplicate the 69/ earlier system
Another is to either leave the 1/4 vent tube in place, and run it "up high" so it won't siphon. Plumb it into the air filter bonnet if possible
One option is as above, duplicate the 69/ earlier system
Another is to either leave the 1/4 vent tube in place, and run it "up high" so it won't siphon. Plumb it into the air filter bonnet if possible
Snake
Mopar Nut
I could do that but when does the money tree stop lol.
Snake
Mopar Nut
You have a good point,a place i buy my mopar parts said to run a line up into the frame doable?
Yes. That is a pressure vent valve on the back side of the cap. When the tank builds up a small amount of pressure, it pushes the valve open and releases it. It is not a totally open vented cap. They are called "pressure vented". It is closed until pressure builds up and opens the valve and releases it.
You can verify this by putting your mouth over the valve and blowing. You can feel the valve release when too much pressure is built up.
You can verify this by putting your mouth over the valve and blowing. You can feel the valve release when too much pressure is built up.
Snake
Mopar Nut
LMAO I have all ready did that.
Well if you were close by I would give you one.
Snake
Mopar Nut
I understand that,but i have nothing any more no line,canister.
I had the same issue. I just welded the end shut on the tank. I then got a length of brake line tubing at Napa and I drilled a hole up high in my filler neck. Then weld a nut to the side of the filler neck over the hole you drilled. Take the flared end of the brake line with the flared fitting and thread it into the nut. Bend the tube up high and then back down through the filler neck rubber seal and out to the frame rail under the car.
Snake
Mopar Nut
67Dart273
Well-Known Member
That will not seal..................
But it's headed in the direction of one "right path."
Options:
Weld a tube direct to the filler as I mentioned earlier
Go ahead and use a nut but do use a 3/8 X SAE fine thread. Buy a 1/8 pipe tape and chase the nut with the pipe tap when you are done.
Then buy a "half union" with 1/8" male pipe on one end, and the correct inverted flare end to fit your tube you are using, such as 1/4" brake tube
The brake tubing fitting MUST have the proper inverted flare seat to seal.
This is what you want below: 1/8 pipe on the male end, whatever angle you desire for the fitting, and the proper size female inverted flare to fit the tube
If you have the knowledge and equipment to silver braze you can also either directly braze the tube into the filler, or you can braze the adapter fitting to the filler.
Snake
Mopar Nut
Well I got a buddy a cross my street that can weld a pop can .,what part your talking about that wont seal Del.Thanks for the tip.
I think he is thinking brass fittings?? When I bought my brake line tube, it already was flared and had a steel male thread 1/4" IPS fitting already in place. I was just going to tap the vent tube and then thread in the fitting and just tack weld it. Hell, I imagine some JB weld would also hold it there and not leak. It is high enough up the tube so as not to see any liquid.
67Dart273
Well-Known Member
A brake tube is indeed flared, but it needs the proper fitting to seat into. A nut isn't it
An inverted flare (brake) fitting on a tube MUST have the female "mate" as shown here
If you just screw the tube nut into a standard nut, there is no internal seat against which it can seal. Pipe thread needs no such seat because they are tapered, and go tighter as you screw it (pipe fitting) in.
So if you can either create a pipe thread, as I said earlier, say, weld a nut or other "boss" to the filler, then chase it for 1/8 pipe, and use one of the brass adapters .....or...if you can braze the brass adapter directly to the filler.
To me, it would be far easier just to do it exactly as the factory did.......braze a short steel tube to the filler "around back" out of sight, then use a very short rubber hose coupler to hook up the remaining vent tube. Very important to bring the tube up "upside down U" then back down through the gasket "outdoors." The originals up through 69--part of 70 went through the floor gasket and ended "open end" in the inside of the rear frame rail stub. I assume this was for protection. You don't expect "much" fuel to ever come out, there.
For these kinds of jobs I use what most used to call "silver solder" meaning hi temp silver braze. I think you could use MAPP gas, but oxy--acet is the usual heat. I don't believe LP (propane) would do it.
An inverted flare (brake) fitting on a tube MUST have the female "mate" as shown here
If you just screw the tube nut into a standard nut, there is no internal seat against which it can seal. Pipe thread needs no such seat because they are tapered, and go tighter as you screw it (pipe fitting) in.
So if you can either create a pipe thread, as I said earlier, say, weld a nut or other "boss" to the filler, then chase it for 1/8 pipe, and use one of the brass adapters .....or...if you can braze the brass adapter directly to the filler.
To me, it would be far easier just to do it exactly as the factory did.......braze a short steel tube to the filler "around back" out of sight, then use a very short rubber hose coupler to hook up the remaining vent tube. Very important to bring the tube up "upside down U" then back down through the gasket "outdoors." The originals up through 69--part of 70 went through the floor gasket and ended "open end" in the inside of the rear frame rail stub. I assume this was for protection. You don't expect "much" fuel to ever come out, there.
For these kinds of jobs I use what most used to call "silver solder" meaning hi temp silver braze. I think you could use MAPP gas, but oxy--acet is the usual heat. I don't believe LP (propane) would do it.
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