Fuel cell vent problems, idea and question, I guess

47convert · June 08, 2009, 01:57:10 AM

My '34 Hiboy coupe has a (Summit style) aluminum fuel cell mounted in the trunk that is filled by a 2" Stainless steel tube that snakes down and around into the tank from a Cobra style aluminum flip top gas filler that is mounted on the top of the quarter panel. There is a 3/8" SS hard line the comes out of the top of the tank turns back to the wall between the tank and the interior and then turns down through the floor to a frame mounted Fram style fuel filter and on to an electric pump and up to the carb. There's also a second 3/8" line that follows the gas line across the wall and down through the floor to atmosphere to vent the tank. The horizontal part of the vent tube and the horizontal part of the 2" fill tube are approximately the same hieght which means I need to be very carefull filling the tank because if I fill the tank up into the fill tube, gas also rises to the level in the vent and spills about a litre of fuel onto the ground. Gas station attendants are starting to get a little ticked with me when I do that and I'm expecting a call from some environmental groups any minute. I was hoping to find a small float style check valve that would seal the vent tube as the fuel got up into that area but haven't had any luck, so my solution, which seems awful long winded to explain is this: I have a front bowl from a single feed Holley. I'm thinking I could make a 3/4" thick aluminum block off plate / mounting bracket that would close off the back of the bowl and allow me to mount it on the wall behind the tank. My plan then consisits of running the vent tube from the tank to the original fill fitting on the front of the bowl, drilling and tapping the aluminum plate at the area where the little aluminum tube would usually go to fill the Holley's rear bowl and tap this to complete the vent tube to outside. I'm hoping the gas will rise in the vent, lift the float in the bowl at the appropriate time closing off the vent and stopping the gas spill. Up until the bowl is full the tank would vent through the needle and seat into the bowl and up and out to atmosphere through the fitting in the aluminum mounting plate. My question is: will the gas in the bowl go back down through the vent tube to the tank as the car is driven and the tank level decreases? Or will it remain stuck in the vent tube? Or, better yet, does anyone know of a float style check valve that I can splice into the 3/8" vent line?

chimp koose · June 08, 2009, 02:22:11 AM

Why not run the vent tube from just below the top of the filler tube to below the trunk floor?

phat rat · June 08, 2009, 08:36:56 AM

I just put a new gas tank in my cpe and it has a check valve on the vent. I got the tank from Tanks in Mn. You might call them and see if they would sell the valve only. It's like that in case of a roll over.

47convert · June 08, 2009, 02:52:00 PM

Quote from: "chimp koose"Why not run the vent tube from just below the top of the filler tube to below the trunk floor?

The flange on the aluminum filler cap is very short, Might be able to do that close to the top though.

wayne petty · June 08, 2009, 02:55:14 PM

i have the stupidest idea ever... why not find a car with a small carbon vapor canister... run the vent line to that... and a purge valve off the ported vacuum source to control the purge valve.. with the purge line to intake vacuum... this would reduce fuel tank vapors in peoples garages...

and properly burn the fuel vapor...

we will have to study how the vapor recovery system works... and try to find a small carbon canister... that could be hidden...

the black fuel filter looking thing in the power brake hoses of GM cars is actually a carbon canister... to protect the power brake booster from fuel vapors...

yea.. i know its a really stupid idea... but if engineered properly.. it would work.....

phat rat · June 08, 2009, 08:31:18 PM

Maybe I wasn't clear enough. The vent that was supplied with my tank is aluminum and is to be put on a line running from the tank vent and mounted somewhere higher than the tank. It's really nice how much faster the tank fills now. Why bother trying to make something do when you can buy one that will work for perhaps not much money

river1 · June 08, 2009, 08:49:33 PM

here is a link that lists some tank accessories from the tanks inc site

http://www.tanksinc.com/index.cfm?ptype=results&category_id=62&home_id=62&mode=cat&start=13

you'll see two different vents listed, maybe one will work for you

later jim

wayne petty · June 09, 2009, 12:15:25 AM

ohh... somebody was looking for one of these 3 port fuel tank valves a while back...

i just cannot remember who it was...

http://www.tanksinc.com/index.cfm/page/ptype=product/product_id=93/category_id=62/home_id=62/mode=prod/prd93.htm

47convert · June 09, 2009, 03:05:40 AM

OK, some good ideas, Thanks guys. My cell has an anti roll over valve, but I don't know if the check ball inside floats. I have it blocked off because I wasn't sure where it's supposed to be plumbed to. These tanks have three fittings welded into the top. One is the fuel line, one is the vent and one is this roll over. I thought the roll over would be for a return line, which I don't have with a carb. If my car was upside down, the bttom of my vent would be at the top of the car and wouldn't be a problem as far as I can see. I guess if I installed the vent in the fill tube, at the top, I would need to block off the existing vet tube. Wayne, I'm going to need to study that idea. Sounds interesting.

34ford · June 09, 2009, 07:50:56 PM

Quote from: "47convert"OK, some good ideas, Thanks guys. My cell has an anti roll over valve, but I don't know if the check ball inside floats. I have it blocked off because I wasn't sure where it's supposed to be plumbed to. These tanks have three fittings welded into the top. One is the fuel line, one is the vent and one is this roll over. I thought the roll over would be for a return line, which I don't have with a carb. If my car was upside down, the bottom of my vent would be at the top of the car and wouldn't be a problem as far as I can see. I guess if I installed the vent in the fill tube, at the top, I would need to block off the existing vet tube. Wayne, I'm going to need to study that idea. Sounds interesting.

I think you have your vent and the rollover turned around. On my tank the vent is the hole in the tank with no extension on it, just a bung welded on the top of the tank, this is where the rollover/vent in installed.

The rollover is a combination of a rollover and a vent. It will vent out in the upright position and seal off in any sideways or upside down position. The ball is held closed by gravity. It needs to have a tube attached to it to get it outside of the vehicle if your tank is in the trunk.

I got a charcoal canister from a junkyard car and hooked it into that so my garage would not have a gassy smell from the vent on warm days.

The tube you are calling the vent I believe is for a return line and could just be plugged off. If my memory is right the return lines always dump into the bottom of the tank.

Here's a pic of the tank. Rollover in middle and fuel on the left. Filler and fuel sender on far right.

The pic of the summit cell from their web site says there is a return line fitting if your tank is similar to the one pictures.

Think you need to block off the vent tube you are using now and hook that line to the rollover/vent fitting and should be good to go.

Maybe you could post a pic of your tank for us to see

bob

47convert · June 09, 2009, 11:32:23 PM

Quote from: "34ford"
Quote from: "47convert"OK, some good ideas, Thanks guys. My cell has an anti roll over valve, but I don't know if the check ball inside floats. I have it blocked off because I wasn't sure where it's supposed to be plumbed to. These tanks have three fittings welded into the top. One is the fuel line, one is the vent and one is this roll over. I thought the roll over would be for a return line, which I don't have with a carb. If my car was upside down, the bottom of my vent would be at the top of the car and wouldn't be a problem as far as I can see. I guess if I installed the vent in the fill tube, at the top, I would need to block off the existing vet tube. Wayne, I'm going to need to study that idea. Sounds interesting.

I think you have your vent and the rollover turned around. On my tank the vent is the hole in the tank with no extension on it, just a bung welded on the top of the tank, this is where the rollover/vent in installed.

The rollover is a combination of a rollover and a vent. It will vent out in the upright position and seal off in any sideways or upside down position. The ball is held closed by gravity. It needs to have a tube attached to it to get it outside of the vehicle if your tank is in the trunk.

I got a charcoal canister from a junkyard car and hooked it into that so my garage would not have a gassy smell from the vent on warm days.

The tube you are calling the vent I believe is for a return line and could just be plugged off. If my memory is right the return lines always dump into the bottom of the tank.

Here's a pic of the tank. Rollover in middle and fuel on the left. Filler and fuel sender on far right.

The pic of the summit cell from their web site says there is a return line fitting if your tank is similar to the one pictures.

Think you need to block off the vent tube you are using now and hook that line to the rollover/vent fitting and should be good to go.

Maybe you could post a pic of your tank for us to see

bob

My tank is exactly like your first one. I didn't use the rollover as a vent because I thought the check, held closed by gravity would stop the fumes from venting. Are you sure the tank will vent through there? Will it seal if the gas rises too far up even though the car is right side up? I have it capped off.

34ford · June 10, 2009, 08:15:35 AM

bob[/quote]

My tank is exactly like your first one. I didn't use the rollover as a vent because I thought the check, held closed by gravity would stop the fumes from venting. Are you sure the tank will vent through there? Will it seal if the gas rises too far up even though the car is right side up? I have it capped off.[/quote]

I have been running my tank for 3 years like that and have no troubles with it. The rollover/vent came with the tank as well as a fuel pickup I had to cut to length and install. I put dowel in the end of my r/v tube to stop it from venting in the garage on hot days and when I would pull out the dowel you could hear the tank venting off, so it will vent with pressure.

As far as shutting off the gas flow when filling to the top of the tank I can't say. I have my venting tube coming out the back below the fender along the frame so if it would start to come out I would see it right away. Haven't filled the tank to max capacity.

With your filler tube in the top of the quarter panel you might have a problem over filling and spilling out. Guess you would just have to check it with the r/v hooked up that way. The ball in there is steel so I don't think it would float up to seal off the vent in an upright position.

C9 · June 11, 2009, 09:05:20 AM

Fwiw - Summit calls their aluminum fuel tank a fuel cell in the catalog, but it's not.

It's an unbaffled tank that can have leakage problems at the filler ring.
Nice tank otherwise.

I run my vent line much like Wayne Petty suggests.

Rollover valve.

Vent line as high up in the trunk as it will go.

Back down through a grommeted hole in the floor.

Charcoal cannister (a steel one) from a late 70's early 80'sToyota pickup I believe. It's located front left under the hood.

From the charcoal cannister (located at the rear of the car) to an Earl's aluminum stainless screen type fuel filter (not the ceramic filter model).

This works like the spark arrestor in the acetylene line of a gas welder.

From there to the clean air area of the air filter.

Done to get rid of the gas smell in the garage and it keeps the vapors out of the atmosphere.

If I can find it, I'll post an article I wrote on the Summit tanks leading filler ring, the repairs and what to look for.

C9 · June 11, 2009, 09:08:24 AM

Found the article.

http://www.roddingroundtable.com/forums/viewtopic.php?t=9935&highlight=

Coupe · June 11, 2009, 01:07:41 PM

I don't know if this is any help but I vented mine from the filler neck and ran a 3/8" tube UP and made a loop and then down and out the bottom. as long as the loop is above the tank there shouldn't be any spillage.
they sell shut off kits for the pump.