Auxiliary Fuel tank filler neck alternative

[ducktapeguy]

I have this issue exactly when filling the auxiliary tank (which is currently my only functioning tank). I'd like to find a way to route the filler so I can fill it at full speed.

I suspect the filler tube going to the tank doesn't have enough slope to move the fuel fast enough, so it backs up and shuts off the nozzle. If I just let the nozzle hang in the filler opening, it actually points slightly upward due to the angle of the tube. If I want it to fill faster, i have to push and hold the nozzle pointed slightly down, and rotate it slightly. Seems to work better, but not great. I think moving the filler opening higher like what other people have done would probably eliminate the problem.

 

[Oregon FJ40]

Removed the leaky, rusty fuel tank/bomb from under the passenger seat and discarded it. Installed a 21 gallon tank under the rear and moved the stock fuel filler to the rear. (Purchased the steel tank from BTB for $900 before they jacked the price way up.) The fuel filler is hidden to a point and there is much less possibility of having the cap ripped off when off-road. Plus it smooths the side which, IMHO, makes it look cleaner.

View attachment 1581599

I really like this look. Do you remember where you got the weld-in filler assembly from?

 

[Downey]

So if we are going to breath some fresh life into this old thread, let me add my 2 cents. If you look at ebay #264758943079, 3rd photo you will see the Downey recessed filler neck. It can be mounted as high as possible while still staying in the wheel well, then would give about a 3" to 4" drop in hose. And while we are at it, look at the 10th photo. That is the very righteous Downey aluminum tank skid plate that fits Downey rear fuel cell, or later Con Ferr tank that had the sloped rear floor. I'd bring these back if there were enough interest- - -lemme know.

 

[GRM]

I just did a replacement to keep the fuel from leaking out the filler neck. I installed a fillerneck off a ~2000 silverado stepside. No leaks. It sits about 3” above the top of the tank, but is bolted below the wheel well.

 

[matzell]

So if we are going to breath some fresh life into this old thread, let me add my 2 cents. If you look at ebay #264758943079, 3rd photo you will see the Downey recessed filler neck. It can be mounted as high as possible while still staying in the wheel well, then would give about a 3" to 4" drop in hose. And while we are at it, look at the 10th photo. That is the very righteous Downey aluminum tank skid plate that fits Downey rear fuel cell, or later Con Ferr tank that had the sloped rear floor. I'd bring these back if there were enough interest- - -lemme know.

Jim is your tank baffled?

 

[Downey]

Nope, it's a actual fuel cell that would be used with fuel cell foam bricks if desired (required on race vehicles). Most guys will not buy the $$$ fuel cell bricks (takes about 12 bricks) because the fuel is at the back of the frame, under the body, sooooo you would never hear fuel sloshing.

 

[ducktapeguy]

Update, I finally got around to fixing my filler neck issues by eliminating the filler neck completely. It's not the ideal solution for everybody, but for my purposes it'll work fine. I'm using my main tank like a transfer tank to pump fuel back into the aux tank. Currently my setup allows me to draw from either tank directly to the engine

Made a plug to seal off the aux filler neck port. 3 o-rings seal to the interior of the filler neck, and the OD matches the OD of the filler tube so I can use the existing filler hose (not shown) to make sure it doesn't back out. I tapped the plug with another plug in case I need to add another port in the future for any reason. Everything sits within the frame area so in case I have another blowout it's not going to take out my filler tube.

To transfer fuel I have an electric fuel pump connecting the supply line on the main tank to the vent line of the Aux tank. I was already carring a spare fuel pump in case the mechanical fails, so I figured i might as well hook it up and put it to use rather than having it sit in my spare parts bag all the time. Now if my mech pump goes out the electric pump is already wired up and ready to go.

You can see where I Tee'd into the vent line going back to the vapor chamber. In theory, when the aux tank is full, the overflow goes back to the main tank. I tested it last night and it seems to work. I still need to anchor all the lines to the frame but for now zip ties are holding it. I may relocate the pump and associated hoses to between the seats, I want to keep everything above the level of the tanks in case there's a leak. The other thing I may do is add a fuel cutoff solenoid in parallel with the pump wiring to prevent gravity feeding or siphoning of the main tank when the pump is off. Not sure if that's a problem right now, but I already have one and it would be easy to integrate.

Because the electric pump is designed for carb engines, it's low pressure (I think around 5 psi) and is rated for 30gph. So it would take about 45 minutes to fill the 22 gallon aux tank from completely empty. It would take at least 2 fill ups to fill it from completely empty because the stock tank that it's drawing from is only 16 gallons. It's not much of a problem since I usually only fill the tank on long off-road trips and have plenty of time to prepare, I've never needed to fill the tank quickly. I also have a timer switch that is going to be triggered off the rear heater power (my rear heater is removed) so when I start the heater it automatically starts a 30 minute pump interval.