How are those of you using mustang tanks venting them?

I've got the somewhat typical/easy '65 Mustang tank in the trunk of my '50 Chevy and was wondering how others of you have vented them outside. I would like to try and keep it somewhat unobtrusive, maybe a circle track style shutoff/vent, or??.

 

Mine is vented out the cap right into the trunk....We welded on a neck from an old suburban with the clicking cap that is vented..... Hope I did'nt build a bomb......... Dan

 

Hey Shifty50,
A friend gave me a 65-ish Mustang tank and dang if it didn't fit right down into the frame rails of my Stude.I used a Triumph TR6 flip top filler and mounted the vent tube (rubber fuel line)to it and ran it out and away from the twice pipes to breath.
It's a wonder there are any Mustangs with factory tanks at all the way that thing fit right into my truck?
Good luck on your project and happy motoring!

 

what happens if you don't vent them? The one in my 59 has the stock 59 vent tube on the filler, but I think it's pinched off

 

If you don't vent the fuel tank it will cave in on it's self as the fuel pump sucks the fuel out and no air takes it's place. Then the engine will stall. If you vent the tank into the trunk you have built a BOMB, change it immediatly. Really!!! When the tank heats up, like when sitting in the sun any gas that evaporates will fill the trunk up with gas fumes and any spark will ignite it. Brian

 

ok, then mine is venting because I've run it pretty low and it hasn't caved in or stalled, and my trunk doesn't reek of fumes

 

I just run a piece of hardline over and out of the trunk area...attach it to the stock vent tube with a little piece of rubber hose. Usually tuck it up in the fenderwell area.

 

Stock vent tube?? All that is sticking up is the bare neck for the stock mustang fill hose that attaches to the cap on the rear panel; outside.

 

ooops...forgot I added a tube (welded a piece of hardline onto the filler neck down low)

 

My 49 Ford tank isnt vented and it works fine. Never had a problem with it sucking and starving for gas. The cap seal is where you get enough air to not have a problem. Most of the old caps dont seal 100% If you run a full tank you dont get as much fumes.

 

i welded a tube to the filler neck on the tank then ran a hard line to the side with a bend going up the 1/4 panel (to keep fuel from traveling out) 180 degree bend and out the trunk floor.

 

Early Mustang tanks are vented thru the cap.

 

good to know, mustang. I have a new, locking cap on my 59, so it may be vented, too. I'll probably weld in a vent onto the Mustang tank going into my Econoline

 

Most cars prior to the 1970's had vented caps that let air into the tank as the gas was removed. Some tanks also had an internal vent that ran up the inside of the fill tube that let air out of the tank as the tank was being filled so the gas pump would not kick off before the tank was full. You can see those just inside the fill tube with the cap removed.

 

Not sure if it will be a problem on your installations, but those of you who have owned early Mustangs have probably had your filler neck "burp" gasoline when you filled it up. The lack of a separate vent caused the fuel to back up the filler neck and when the nozzle cut the fuel, whatever was in the neck would slosh out and onto your bumper and rear valence. Messy!

 

And ruin a paintjob if left to sit too long........

Vented caps are for fill necks that exit the vehicle. If the neck is inside the trunk, use a sealed cap and run a vent tube (soft or hard line) outside the car (like Brewsir and a couple guys mentioned). Something like this...



You should be able to find a fill neck at a junkyard...I got one off a postal Jeep.

Bryan

 

It was more a question of how people have run a vent tube than the fact that it needs to be vented. Good ideas, I think I'll end up welding a small tube on the existing neck as stated and hardlining it out through the front of the trunk. Thanks again all.

 

I'm so glad you asked. I wanted to vent my fuel cell, but didn't know if I should or if how or if it was necessary or or or or or......yah I know, but I already knew a non-vented tank was a problem and then venting into the trunk was a bigger.

I'm going to plate up the rear seat into the trunk so it's kind of important to me to know.

 

Here's how I ended up doing it, and no it is not vented into the rear end housing, the end will be turned upward into the notch cover with a loop, filter, or whatever at the top. I would have like to put it up a little higher in the fill neck, but there is a weld there and I didn't want to tap through it. I know some of you may be thinking it'll just slosh fuel up and out, but I'm hoping physics and the fact that a running vehicle should have slight vacuum from the tank will prevent this. Any thoughts? Good or bad, now would be the time to fix it as there hasn't been fuel in it yet.

 

I put a roll over (checkd) valve on the end of my vent line. think it was a Corvette item.

 

That's a good point, I never thought of trying to avoid putting fumes into the pocket of potentially stale air created by the notch. May have to rethink my line routing. Thanks.

 

If you are not going to run a taller set up then do like shifty50 did, or find yourself a connecting tube. I used a 40 ford unit and had a muffler shop expand one side of a piece of exhaust tubing to match the mustangs larger side. the 40 filler tube had a vent and I just connected it to a piece of rubber and ran it out of the car..



if you look close you will see a vent tube on the top portion of the filler neck.

 

That setup is the shit. Perfect use of space, very neat!-MIKE

 

I have a Mustang tank in my 37 Plymouth the tank has a vented gas cap that allows air into the tank as fuel is used. It also has a two inch feed line however Ford didn’t use a vent tube to vent the tank. This wasn’t needed because the fill tube length was short and the 2 inch diameter allowed the tank to vent when filling through the fill tube. I am using a fill line about three feet long this causes the incoming fuel to block the exiting air and burp out gas from the fill tube. What have you guys done to remedy this situation? Thanks Hobo Jim

 

I weld bungs into them for vent, and a potential future return line (if the customer wants to add EFI, or just a bypass regulator to help with vapor lock). I attach a rollover valve to the bung, and run the vent outside the car, making sure that the line runs above the highest possible fuel level, filling, and driving on a steep grade.

I buy my parts here: https://www.fillernecksupply.com/

I ONLY weld on brand new tanks. These tanks are cheap. If you need to weld on one, just buy a new one.

 

Put in a large diameter bung, and a hose barb. Put a similar one right at the top of the filler. Connect with a fuel-safe hose.

 

Would running a 1/2 ID hose inside the filler neck stopping at the end of the filler tube or an inch before the end do the same thing since the ID of the filler neck is two inches there should be room for the gas nozzle or is a 1/2 ID overkill

 

I have not stared at the nozzle of a gas pump in a while. I think that they are about 5/8". I would want to match that size, or exceed it. After all, that is what is delivering fuel to the tank, so you want an equal potential displacement.

As an alternative to getting dirty looks for busing out the calipers to measure the ID of the fuel nozzle, it says the ID on the hose leading to the nozzle. If you meet, or exceed that, and make sure that the bottom end is not submerged, you should be good. A fill vent does not know if it is outside the fill hose, or inside of it. It's just a dumb hose.

 

Ha Ha so in other words I have to be smarter than the dumb hose boy am I in trouble now!