71 gas tank??

[hotrod ford]

Do you need to have the tubing to the charcoal canister connected to a 71 gas tank or can you plug the two tube coming from the tank?

[fordman]

you can plug off the vent. and use a vented gas cap. or just leave the tube hooked up and use the same old gas cap. either way works.

[D.J. Wyman]

I swapped a 72 gas tank to my 71 and just removed the charcoal canister completely. I did however have trouble getting a vented gas cap. It needs to be pressure vented not vacuum vented. Thats the problem i encountered.

[basketcase0302]

D.J. Wyman on Sun Aug 14, 2011 11:47 am
I swapped a 72 gas tank to my 71 and just removed the charcoal canister completely. I did however have trouble getting a vented gas cap. It needs to be pressure vented not vacuum vented. Thats the problem i encountered.

I'm beginning to believe that no one actually carries one anymore, (vented cap) after two attempts to find one on my part.
If it were mine...I'd leave the charcoal cannister hooked up, much more reliable venting on the fuel tank. Still wondering why Ford put vented tanks in some of our 71's and some did not get them.

[fordman]

F100 got the vent tanks and F250/350 didnt get the vented tanks.

[basketcase0302]

fordman on Wed Aug 17, 2011 10:18 pm
F100 got the vent tanks and F250/350 didnt get the vented tanks.

Yet another mis-management insane decision I presume...

[fordman]

government regulations.

[hotrod ford]

What does a vented gas cap look like compared to a no vented cap?

[BobbyFord]

Here's what I encountered on my '72 F100 before I did the Mustang fuel tank swap...
My truck came with the vented tank and emissions canister. At 1/2 tank the truck would die from from fuel starvation because the charcoal canister was plugged. I tossed the canister and swapped out to a non-vented tank (which required the use of a vented cap). I went to get a vented cap and found out that the fill pipes were different between the vented and non-vented tanks. I swapped fill pipes and was able to get a vented cap.

[fordman]

i think the cap difference is the depth of the twist inside of the cap. one of them may be deeper. i do know that one wont interchange with the other. because of how the fill tubes are made.

[basketcase0302]

Thanks for posting Bobby, it makes sense to me. But why Ford would change the part#?

[Florian]

I removed the charcoal canister and the fuel line that went to it from my 71. Cut the fuel line where it exits the cab. Didn't get a vented cap and everything works fine.

[BobbyFord]

i think the cap difference is the depth of the twist inside of the cap. one of them may be deeper. i do know that one wont interchange with the other. because of how the fill tubes are made.

Correct, the difference is the depth of the twist. That's why you cannot find a vented cap that fits the depth of twist for a vented tank style fill pipe.

[cdeal28078]

I'm going to have to look at mine now. I had some what I thought was vapor lock problems a couple years ago. I still have the can that is hanging on the front right frame rail though it does not run up to the breather. I do think the rest is still hooked up coming from the gas tank. I wonder if it was that causing my troubles. Having had any more troubles though
clint

[hotrod ford]

If the gas tank could not vent, would that cause an engine to shut off?