Fuel tank & filler venting

[JeepSnake]

Hey guys,

I did a search, and turned up a few pics & descriptions, but nothing really detailed.

I'm encountering the fuel burp problem with the FIA when filling the tank. Basically, I wind up dribbling the fuel in and listening very carefully to make sure I don't go too fast and get fuel belched back out and onto the paint. On examining the tank & plumbing, the car has a small standpipe with a loop in it, similar to that shown in a photo posted by Phil Germond.

So, does anyone have a sure-fire solution for venting the tank on the 289 cars so that this doesn't happen? Photos would be outstanding. (Rick, I already emailed Juan to see if he made any photos of the arrangement you put on his car. I read a post you had made, but didn't really see where you told how you wound up setting up the vent on Juan's.) In addition to changing the existing vent to a better setup, do I need to tap in and run a dedicated filler vent like on a typical fuel tank?

Just trying to get this worked out before we start driving a lot this season - it's getting to where I dread having to fill up.

Thanks in advance!

[eliminator]

The vent on the tank will work, on some of them Unique made a little pig tail curl and left the 1/8" line pointed up. After a while they get clogged up with small debris, dust, and dirt. Just take it off and get a short piece of brake line and make a new one, have it go as high as possible then point down instead of up so it wont collect debris. I bet yours is restricted.

[nolastyankee]

Guys,
Glad this topic came up because we are looking at running our fuel tank vent a little differently on our car.

The LeMans filler cap has a hole through it and allows a significant amount of air to flow through, I would assume to allow the tank to breathe. Knowing this, has anyone considered venting the tank back into the filler tube at or just below the filler cap? When adding fuel to the car, the system would be pretty much open unless you fill all the way up the neck to the cap. (Then you have another problem) When the filler cap is down, the hole through it should allow enough air movement to enable fuel flow. At a minimum, the hole in the filler is the same diameter as 1/8" brake line that the factory vent uses.

Any thoughts?

[spd4me]

For the first year I had my FIA I would have to fill the tank as slow as I could to prevent it from coming back out. I disconnected the large hose at the tank and discovered the tape over the inlet was still in tact. Removed the tape and haven't had problem since. Also my air tubing that went up into wheel well was flattened on the end. I replaced it and added a section of gas hose down to rear of wheel well so it wouldn't drip on frame.
Bob

[ralphscott]

The end of my vent tube is also flattened. That is the way it came from Unique. It works fine. There is enough of an opening to let air bleed out or gass if I over fill into the filler tube but small enough to keep the debris out.

Ralph

[nolastyankee]

Bob,
You probably realize already, but you should ensure that when adding line to the end of the Unique vent that the end remains a couple inches above the highest level that fuel can be in the tank. If you add hose all the way down the frame rail you can create a siphon that will empty your tank onto the ground under the right conditions.

[spd4me]

That's a good point. Maybe that's why my mileage is so low. If I can keep the top of the loop higher than the tank and never fill all the way up to cap, I guess I'll be okay.

[nolastyankee]

The vent exists to move air only. If it is dripping there is another problem altogether! There should truly not be any need for a drip extension.

[spd4me]

The reason for the original driping was when filling with gas the gas level was always at the top the gas cap because it was going in so slow which pushed the level up through the air vent tube. Since I took the masking tape off at the gas tank inlet, haven't had problem.
Bob

[Jeff 427]

I did not like the open brake line vent for the fuel tank.
What I came up with was a "protected vent" valve from grainger.com,
part #1u569, about $6.00. I adapted it to fit the line and pointed up.
It seems to work fine and hopefully will keep gunk from getting into the tank!

[spd4me]

Jeff - have you got a picture of that vent?
Bob

[Aggressor]

Talk about timing for this topic.....My SC belched back fuel three times while refueling on Friday. The first belch was a beauty splashing the rear fender and, to a lesser degree, my pants and shoes. Totally unexpected and out of character for this car. This is a first time event after six years of ownership and it occurred where I routinely get fuel. I'll be checking my vent for blockage.

-Geary

[ralphscott]

Don't ya just love the smell of high octane!

Ralph

[Aggressor]

The smell of high octane is fine for a while but when you tire of it Dawn dishwashing liquid applied undilluted works.
Scrub in with a brush and then rinse.

-Geary

[Jeff 427]

Bob,
Here is the picture of the "protected vent."

I hope picture attachment works!!! ........ this is a first for me!!

[ralphscott]

Looks Great!!

Ralph

[eliminator]

Jeff that will work but I dont think you went high enough with it.

[scott h]

your photo looks like your vent is inside the trunk. i would be concerned about venting inside your trunk. there is always that off chance of a wiring short or arcing problems from the battery or the switch, BOOM!

[Jeff 427]

Ralph - Thanks!

Rick - I flared a fitting onto the vent tube that Unique made for the car and it made it about 1" higher with the protected vent. How much higher should it be?

Scott - I see your point if you look at the picture quickly!! It is an illusion and appears to be inside the trunk ..... that would not be good!!! Bad things could happen!!! It is in the outside wheel well and I also put boots over the terminals on the cut off switch.

[TurnpikeBoy]

This is excellent. I've been unhappy with the vent ever since putting it together; and from the stains in the undercoating in the wheelwell and on the frame below it, it's obvious that there is some run of fuel out of it. Thanks, Jeff.

Now - the only issue to deal with is how to get one out of Grainger since they tell me they only sell wholesale, i.e., to a business. Which I ain't. Eh - where there's a will, there's a way.

[eliminator]

I would make it another 2 inches higher. Just look at the top of it in realtionship with the fuel filler, If you had fuel in the filler neck up close to the cap which would be higer? If the fuel in the filler neck gets higer than the vent it will push the fuel out the vent.

[Jerry Cowing]

I drive a 427 S/C, but I might have an easy solution for you. Why don't you try running a 1/8" copper tube down the inside of your filler tube. Make it long enough so that it extends just past the bottom end of your filler tube (just guessing, but let's say 3 feet long for an FIA application). You want to keep the bottom end of the copper tube out of the gas in the tank, but long enough that it extends past the end of the filler tube into the tank's air space. Attach the top of this copper tube to the inside of the filler cap frame so that when the filler cap is closed the top of the copper tube is sealed against the rubber gasket.

Reasoning: When filling your tank, the air is being displaced and pressurized by the fuel filling the tank. The air has to go somewhere, so if you give it an escape path, other than the filler tube the fuel is passing through, the air can escape and not burp back up and out of the filler tube. When filling the tank, the incoming fuel will pass down and outside this 1/8" copper tube and the air will simultaneously pass up through the inside of the copper tube thus deceasing air pressure and preventing burping.

[Naumoff]

I made my own gas tank vent and charcoal filter out of black pipe and fittings and a vent limiter from a natural gas regulator.

[sllib]

Try these folks: www.mcmaster.com.
Bill Stradtner

[TurnpikeBoy]

Thanks, Bill, looks like they may have something.



I made my own gas tank vent and charcoal filter out of black pipe and fittings and a vent limiter from a natural gas regulator.

Hee, hee, heeeeeee.........plummers..........didja put the wax ring under the seat?


-Roger

[Naumoff]

Thanks, Bill, looks like they may have something.




Hee, hee, heeeeeee.........plummers..........didja put the wax ring under the seat?


-Roger

Yes. On the passenger seat with a hole cut in the middle.
No messy clean ups after I give someone a ride.;) :D