Thread: venting?

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Hoping someone can answere this question.

Is there a simple way to vent a gas tank? (without just pokin' a hole in it)

My old truck still has the original tank and filler tube set up and I'm gettin' tired of reaching out the window to relieve the pressure every couple miles.

Originally posted by musicman
Hoping someone can answere this question.

Is there a simple way to vent a gas tank? (without just pokin' a hole in it)

My old truck still has the original tank and filler tube set up and I'm gettin' tired of reaching out the window to relieve the pressure every couple miles.

get a cap with a vent built into it. drill a little hole in the one you have.

well thanks for the reply.

The cap I finally found that fit this thing was supposedly vented.
I'm guessing that when it's turned down it's closing up the vent to tight. Being as I've had the filler tube plated, I'd like to keep it in there.

Dilling a hole in the cap? There has to be a better solution.

Any other suggestions?

If I had to do this on my own truck, here is what I would do. Drop the tank, find a good place to drill a hole in it, put a nipple in the hole, attach a piece of rubber hose to the nipple and run it up to the same height as the filler neck, up under the body. Then put a goose neck in the hose with a fine mesh screen over the end with a pipe clamp, and bango, you got your self one vented gas tank that looks just fine, and no one will ever see the vent. Just what I would do, you may not like to do it that way, as you said you are not keen in just drilling a hole in it, but....this is more than JUST drilling a hole, it is making it more functional. Ain't that what we are all about? Making our rides a little more what we need and want?

Just my opinion.

i'd drill a hole on the highest spot on the fill tube & then solder in a nipple of some kind. then plumb in the hose or tubing u'll use & route in outside. another thing i always do is put a small inline filter at the very end to keep out anykind of dirt that mite get in the tank because of how is expands & contracts...joe

Thanks for everyones input.

The only cap I've been able to find that will fit this thing is made by Stant, locking or not. Neither it turns out are vented. Although looking at the inside, theres a piece in there that has 5 little holes in it and derned if it don't look like some kind of venting set up. EPA strikes again. Cured my problem though. Buddy of mine has an old Packard Roadster and I went and looked at his cap. Small hole drilled in the lock down ring and thru the spring plate. Doesnt go all the way thru the cap. Had to remove that inner plastic piece with the fake vent holes though, problem solved.

I would like to know, if anyone can tell me, what is causing this tank to build up pressure? Is it all due to heat? Exhaust does run right along side it. But it happens in short time.

I would think that as much as that carb drinks, it would create a vacuum.

Originally posted by musicman
Thanks for everyones input.

The only cap I've been able to find that will fit this thing is made by Stant, locking or not. Neither it turns out are vented. Although looking at the inside, theres a piece in there that has 5 little holes in it and derned if it don't look like some kind of venting set up. EPA strikes again. Cured my problem though. Buddy of mine has an old Packard Roadster and I went and looked at his cap. Small hole drilled in the lock down ring and thru the spring plate. Doesnt go all the way thru the cap. Had to remove that inner plastic piece with the fake vent holes though, problem solved.

I would like to know, if anyone can tell me, what is causing this tank to build up pressure? Is it all due to heat? Exhaust does run right along side it. But it happens in short time.

I would think that as much as that carb drinks, it would create a vacuum.

if you have a gas tank with a fuel pump hooked to it with no vent you will have a vac. ive seen them suck the tank flat, but most of the time it will suck a rubber hose closed so gas cant get through.
i would think when you take the cap off it would sound about the same.

Mike, the sound would be about the same I guess.

But, what brought my attention to this one day was coming out to the parking lot where I had parked 15 minutes earlier and finding gas dripping under the truck. It was coming from the sending unit gasket. Since then I have limited myself to half tank fill ups and relieving the pressure continuosly. When I unscrew the cap in feels like air coming out not going in.

Originally posted by musicman
Mike, the sound would be about the same I guess.

But, what brought my attention to this one day was coming out to the parking lot where I had parked 15 minutes earlier and finding gas dripping under the truck. It was coming from the sending unit gasket. Since then I have limited myself to half tank fill ups and relieving the pressure continuosly. When I unscrew the cap in feels like air coming out not going in.

all i know is on the tank side of the fuel pump the pump is sucking and on the carb. side the pump is pumping. in my mind if the pump is sucking and there is no vent then you are pulling a vac. on the tank. just something i have always belived, i guess i could be wrong. but i dont think so. its causing some heat build up and the gas is expanding.

i guess its like a wind noise in a car. if you have a wind noise around you door glass, going down the rd. is that air coming into the car or air being pulled out of the car?

My fuel tanks build pressure, you probably have a vacuum relief built into your cap. My tanks builds enough pressure to give a pretty good pressure burst when I open the cap. It used to leak from the sending unit. I found that the sending unit o-ring was not even in place. It seems that my wife had tanken the car to Nissan for a recall due to some type of fuel pump problem. WEll it seems nissan created a new problem with fuel leaking.
You may very well have a sending unit gasket problem that needs to be tended to.