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I have a tanks, inc EFI tank on my 69. I ran the vent to the upper inside of the passenger quarter. It’s been fine up until I put it away this week for winter storage. I filled the tank up completely for storage and had fuel leak out of the vent. I placed a container and caught the overflow which was only a few ounces.
my question is I’d rather not have this happen again, especially being right over the muffler. I run a vented gas cap on the tank and am wondering if this is enough that I can cap the vent? Has anyone capped off the vent? The vent is already in the highest spot in the car.
My 68 came with a lockable & vented gas cap when I bought it. Big hole right through the top of it--- never had any problems with gas leaking. Are you sure your gas vent is free and clear? I'll see if I can find a picture.
I’m not saying it’s leaking from the cap. The tanks, inc gas tank has a vent line with a valve that needs to be mounted higher than the tank. I’m a C3 that is impossible outside of cutting the body. When the tank is filled 100% it is higher than the tanks, inc vent valve and drips out until level.
Gotcha. Went I modified and installed the 82 sending unit in my 68 I added a piece of tubing that sits about maybe an inch higher than the top of the gas cap. So far it has not leaked nor dripped. I was going through all kinds of ideas until I just decided to try it. It is actually off to the driver side next to the gas cap....so that even if it did drip it would not drip onto the muffler.
The vent on the Aeromotive Phantom Pump - manual said the vent should be 6" above the tank and use a roll over valve. In a Vette to do this the vent would have to be a couple of inches above the rear deck!!!
So I added a roll over valve- connected it to a charcoal canister and then a vent used in marine applications placed in the antenna hole. I also ended up going w/ Russel Synthetic rubber hoses to hopefully stop the permeation of the ethanol in the gas - and gas smells.
I am also running a sealed cap as well-
roll over valve
Vent for boat hulls-
Vent in the antenna hole-
Attwood who makes the thru hull vent you are using also makes several that are flush to the mounting surface.
A marine charcoal canister to eliminate any fuel fumes emitting into the garage or around the car.
The tanks inc. vent is a roll over valve. It stops the fuel from puking out if the car ever goes painted side down. It's not a check valve like the factory unit. When you filled the tank to the brim, the gas expended, the vent hose didn't have the volume to hold the amount expanded fuel and the gas came out the vent.
I unscrewed the screen cover from the roll over valve and used a 1/4” NTP fitting to reuse the charcoal filter configuration. I used a relatively long vent hose to the roll over valve that might help if I ever fill to much.
my question is I’d rather not have this happen again, especially being right over the muffler. I run a vented gas cap on the tank and am wondering if this is enough that I can cap the vent? Has anyone capped off the vent? The vent is already in the highest spot in the car.
thanks!
My thought was you only need one tank vent. If your gas cap has a vent, just plug off the tank one. If not just get a vented cap. Keep it simple. The high tank vent (top left corner) on my 72 tank is part of the vapor charcoal canister emission system, and it has a little check valve, a hose to the charcoal canister, etc etc. That system requires a sealed cap for it to work. That stuff got added somewhere around 70 or 71. You could add all of that. But if you do not need it, then why bother.
If the tank or vent is not sealed thru a charcoal canister you may smell some fumes in the garage. You may smell some fumes anyway with a carb with the bowls being atmospherically vented. With EFI maybe not. It all depends if you are worried about the odors.
Another thought is you could run the open vent hose up to the top of the tank where the gas cap is, attach it to the rubber "overflow catch bowl" seal. That already should be there and it drains over the top of the tank thru a hose that goes into the rear bumperette. And it is far away from the mufflers.
The fuel vapor canister IS the fuel system vent on cars with that system operational. And if you have that system, you do not want to add another vent.
Tanks, inc vent problem
