Gas tank vent?

[PDW HOTRODS]

I installed a 1970's car gas tank under the back of my 53. It has 2 lines coming out by the sending unit. One is the 3/8 line to feed the engine, the other originaly went to the return line from the fuel pump I think. I know they also had a charcoal canister for a vent to go to. I am running a fuel pump with one inlet and one outlet, no return line. What should I do with the second line at the tank. I would like it to vent somehow so I don't get a vacume in the tank, but I think it would be a bad idea to let gas fume just flow under the truck. Is there a filter to cap this line? My gas cap has no vent either. Thanks.

[63 & 64 Bowties]

Doesn't that return line go as "deep" in the tank as the suction line? If so, I would worry about a siphon effect if you used it as a vent, unless there's an inline check valve still there.

[OrrieG]

If its a true vent run a hose with a roll over filter used for racers up the nearest stake pocket. If it is as deep as the pickup line then just cap it off with a hose and fitting and run a vented cap. If the inlet is out the back you may run into problems going up steep hills, I had a late 60's chevy tank as a second tank in mine. In hilly country had to make sure I was running off the main tank and had a non vent cap on the back. Around town did not have any problems as long as the tank was down a few gallons.

[truckdude239]

i would just cap it off and add a vented gas cap

[PDW HOTRODS]

http://www.yogisinc.com/detail.cfm/-...m=Yes/zoom.htm
This is the type of cap I alread have. The return line stops at the yery top of the tank. My cap is already installed, and I would like to leave it if I can. Is there some kind of one way valve for a vacume line I can put on the end of that vent line? I know power brake boosters use a one way valve, maybe I could make one of those work.

[63 & 64 Bowties]

I'm not sure you'd want to go that route. I think you need PV venting (pressure & vacuum) otherwise, what will happen if you fill the tank and night when it's cool outside, then park it in the daytime sun?

[OrrieG]

Originally Posted by PDW HOTRODS

http://www.yogisinc.com/detail.cfm/-...m=Yes/zoom.htm
This is the type of cap I alread have. The return line stops at the yery top of the tank. My cap is already installed, and I would like to leave it if I can. Is there some kind of one way valve for a vacume line I can put on the end of that vent line? I know power brake boosters use a one way valve, maybe I could make one of those work.

I mentioned it in my first post here is a link.

http://www.summitracing.com/parts/BOB-90921/

There are at least half a dozen more there.

[hotrodrookie]

Im getting ready to plan out my fuel system and Im going to be running an under bed tank. Im I ok with running a vented gas cap or should I tap the tank and plumb in a rollover vent/valve? Can the rubber hose be run below the tank or should it stay above the level of the tank in the fender well?

http://www.yogisinc.com/Detail.cfm/-...vv/product.htm

[Tri5Nerd]

Originally Posted by hotrodrookie

Im getting ready to plan out my fuel system and Im going to be running an under bed tank. Im I ok with running a vented gas cap or should I tap the tank and plumb in a rollover vent/valve? Can the rubber hose be run below the tank or should it stay above the level of the tank in the fender well?

http://www.yogisinc.com/Detail.cfm/-...vv/product.htm

I think your computer has that information programmed into it, to automatically cut the fuel to the tank if there is a incident. I remember reading this on another (LS1)forum.

Tri5

[hotrodrookie]

I dont mean to hijack, but the reason I asked, is im gona run a pump similar to the tanks inc pump and I figured I should vent the tank. The screw in tank vent stops fuel from pouring out if ever turned over but mainly serves as a vent for fumes to exit the tank.

Any info on routing the vent tube?