fuel tank venting

Okay guys, need a little guidance here. I have fabricated an aluminum fuel tank for a truck ( '50 chevy body on '80 GMC 3/4 ton frame). I am wondering if I need to install a vent valve in it or will a venting cap be sufficient? My best guess is that the venting cap will be sufficient for all but filling where the cap will obviously be replaced by the modern style filler nozzles which seal around the filler neck allowing pressure to build up and making it very difficult to fill the tank. I have been looking at the rollover vent valves that I can purchase as a good solution to this problem but they all have an AN fitting outlet and honestly i'm not sure what this would connect to, a charcoal canister? Thanks in advance for your help and Happy Memorial Day!

 

www.tanksinc.com has NPT rollover valves. Just run hose outside of closed space.

 

what are you using for filler neck that the gas nozzle covers it completely? i would think a neck and cap as big as a stock `50 chevy pickup wouldn't be a problem

if you do want to install a separate vent/rollover...Tanks sells one that just goes on a 5/16" hose. then you mount it higher than the tank

http://www.tanksinc.com/

http://www.tanksinc.com/index.cfm/p...category_id=62/home_id=62/mode=prod/prd98.htm

 

I'm at the same place with mine. My fuel cell has a -8 AN fitting with a rollover valve in it. I planned on just running a line down under the bed. My problem is fumes as my hotwater heater and pilot light is down in my shop. How can I vent but not build up fumes?

 

Here is what I did for a tank vent.

http://www.jalopyjournal.com/forum/picture.php?albumid=2423&pictureid=78801

The vent/roll over valve is from Tanks Inc.

Rich

 

Tipover valve is a bit overkill. If you add a vent remember to get a small filter for it, for every gallon of fuel going out there will be a gallon of air coming in so you need to keep it clean, it'll keep mud-daubers out too.

 

Chaley:

In your case you could easily do a Charcoal Canister deal like this...

http://www.fordmuscle.com/forums/en...-canister-hookup-your-car-cure-gas-stink.html

And Roll over valve IS NOT OVERKILL

Have you seen a Car tip over with an open system??? I have and it aint pretty.

Be safe. Happy Memorial day and God Bless our Service People..

 

look at an original gas filler neck-have a small breather tube running off of them-also search aftermarket tanks for ideas on venting. Do not have to install roll over valve or carbon canister (unless you want to). Just use rubber fuel hose that runs to a high point on frame.

 

What ever you do add a vent.

 

If you vent from the tank back into the filler tube, attach the vent tube high on the neck of the filler and the tank will accept fuel easily.

 

Okay, you guys are awesome, I think I'll probably use the tanks inc. vent to get things rolling and then I can make changes later. I'm not sure if I will have trouble filling it or not, just doing some hypothetical troubleshooting to try to save myself some trouble. Thanks again for all your expertise.

 

How far above your tank is this vent? I know the vent has to be above the tank, does it need to be just above it??

 

Why does the vent need to be above the tank? I thought the primary purpose was to allow for expansion/contraction of the vapors. I was planning to run the vent line below the car. Any reason to avoid this? Thanks

 

I placed it above the level of my gas cap. This is to keep liquid gas from exiting your tank through the vent line. If you want to vent below the gas tank you can loop the vent line above your tank level. This will also work.