Double gas tank

[Logs0012]

Alrighty. I'm buying the bed for chuckchili's 1966 gladiator and i am thinking about rigging up a second gas tank for my trucks massive appetite for gas. Any suggestion on switches how to run the line?

[Tornado230]

Have you considered using a system similar to the factory setup used on the '74-'78 J-trucks? No switches necessary.

[Logs0012]

I wan't even aware that there was a factory option for dual gas tanks. I was just going to rig something up with 2 J-2000 tanks and filler necks.

[Tornado230]

The factory set-up had a 15 gallon tank in the front corner of the bed.
The fill pipe is near the top of the bed. Tank is connected to the lower standard tank. Fill one, fills both. Total capacity 33 gallons.

[Logs0012]

I was going to try and get 2 full tanks for 36 gallons that way i can maybe stop as many times as my dad when we go on long hauls.

[KaiserMan]

Look hard and you can find them on the 68-73 J3800/J4800's as well. Simple system, and it would be easy to duplicate. Someone probably has some factory drawings or pics.

I don't think they where offered on the short wheel base trucks though. At least not from 68-73.

[Logs0012]

I was thinking something like the 1990 Ford Lariat where it has a tank in front and in back of the drivers side wheel well.

[Tornado230]

The '74-80 parts book has a very good illustration of the system.

[Logs0012]

I still want to go with something Semi custom. that and I will need those extra 3 gallons O' gas on the road.

[KaiserMan]

Lots of people have added in tanks where the stock spare goes under the bed. You could add one in and use some type of stock tank selector switch from a GM or Ford. Might have a hard time getting a sending unit that will work with your guage though. Not sure what is involved with filler/vent hoses.

[Logs0012]

What I would do is take the stock setup from the bed on my truck now and modify the box so it you have 3 sides instead of 2. then just bolt everything down. Hope that there will be enough room under there for the spare still :o

[Logs0012]

just had an epiphany. figure out which wires go to the sending unit, splice a switch in there and kind of make it like a double sided knife switch. turn the switch one direction to get gas from either the front tank then turn the switch in the opposite direction for the rear tank. When the switch is facing one direction it is completing the circuit for one of the sending units while the other unit lays dormant, as soon as you flip the switch the front sending unit goes dormant and the rear sending unit goes online.


Sounds like it will work to me.:D

[jaber]

I have found a Chevy style switch in the one I have. Its on the floor by the drivers seat and it switched fuel delivery and guage. I believe I even have one loose to get you a pic of.

[Logs0012]

I have a hole in the dash that I need to fill and I might try and do the setup I explained in my last post.

Does that sound like it would work? I don't know much about electronics but i know enough to get me buy, so I'm asking you all.

[Logs0012]

Any thoughts?

[TooRisky]

Why duel tanks...look into one bigger tank...I have on my 77 Chero a 40 gal. tank from Aero tanks, made for Jeeps and comes with sending units...here is the url to their site...

http://www.aerotanks.com/veh/jeep.htm

good luck

[Logs0012]

I already have the second tank, thats why. I wouldn't have to spend the money on a larger tank.

[jaber]

I was mistaken the set up on my J. It came with the Trail Blazer aux. tank set up and the fuel lines were switched on the floor, but only having one tank in, there is a hole in the dash where the guage switch was.:banghead: There is even a sticker on the lower dash around the hole with the name and aux on one side and main on the other.

Its been done for a long time, so I dont think it would be a problem. IIRC, even the older f*rds used a similar setup.

[Logs0012]

Jaber: do you think the switch layout that i explained would work? that way you are only using on gas gauge.

[KaiserMan]

just had an epiphany. figure out which wires go to the sending unit, splice a switch in there and kind of make it like a double sided knife switch. turn the switch one direction to get gas from either the front tank then turn the switch in the opposite direction for the rear tank. When the switch is facing one direction it is completing the circuit for one of the sending units while the other unit lays dormant, as soon as you flip the switch the front sending unit goes dormant and the rear sending unit goes online.


Sounds like it will work to me.:D

Wouldn't that just switch sending units? How would you switch fuel flow from tank to tank? You idea would seemingly work if you had electric fuel pumps and could kill power to one while powering the other.

[Logs0012]

How are the sending units powered?

[KaiserMan]

The sending units have a power and a ground (no idea where they pick the power up from), but all they do (in conjunction with the float) is tell fuel the gauge what to read.

You would need some sort of valve to seperate the two tanks from one another so the pump will only draw off one tank.

[COLOFIREMAN]

You would need to use a 6 pin, 3-position 12-volt switch. The gauge goes on the center pin and the leads go on the outer ends.

http://www.action-electronics.com/grc/gc35112.jpg

The tanks need a 6-hole fuel solonoid that one can get from any Napa around.

http://www.bcbroncos.com/6-PORT-VALVE_sb2.jpg
The one you would get from Napa would only have one wire. 12-volts to it and it switches the fuel draw and return line to the second tank.

Or if you like old-school here's a brass one with a return....
http://www.jamestowndistributors.com/userportal/woeimages/Engine/8991.jpg

[Logs0012]

Would I need a second gas gauge for that?

[COLOFIREMAN]

Would I need a second gas gauge for that?

No, same gauge just wire the single wire lead to the center of the 6-pin 3 way switch. When you switch it up it'll send the pulse to the front tanks sendind unit, an down to read the other. Fuel gauges on our Jeeps work on resistance. As the sender goes up it reads more showing more fuel and vise-a-versa. You can see the pulse by taking a test light and checking the lead at the tank, it'll pulse. If it was me, and I have, I would wire the gauge on the switch and the fuel line using the brass valve. Takes the guess work out of which tank your pulling from if there's a fuel problem.:thumbsup:

Edit: make sure you use a electric fuel pump, lessens the air gaps when you switch or run out of fuel. Here's one with 3-ports, no returns, and the fuel pump is staged between the engine and the valve.

http://www.film.queensu.ca/cj3B/Photos/Owners/George/TankSolenoid.JPG

[Logs0012]

I'm beginning to like th giant brass valve idea.:p

I'm not exactly sure if I follow on the wiring for the gauge and the way to differentiate between the two tanks.

[Geminiroq]

No, same gauge just wire the single wire lead to the center of the 6-pin 3 way switch. When you switch it up it'll send the pulse to the front tanks sendind unit, an down to read the other. Fuel gauges on our Jeeps work on resistance. As the sender goes up it reads more showing more fuel and vise-a-versa. You can see the pulse by taking a test light and checking the lead at the tank, it'll pulse. If it was me, and I have, I would wire the gauge on the switch and the fuel line using the brass valve. Takes the guess work out of which tank your pulling from if there's a fuel problem.:thumbsup:

Edit: make sure you use a electric fuel pump, lessens the air gaps when you switch or run out of fuel. Here's one with 3-ports, no returns, and the fuel pump is staged between the engine and the valve.

http://www.film.queensu.ca/cj3B/Photos/Owners/George/TankSolenoid.JPG

Not to beat a dead horse...but is there a dummy down intructional form that I can use to make this happen. I am wiring challenged.

My chero had...the trailblazer unit but the PO removed it for an aero 40 gallon main tank. I want to put the trailblazer back in and like I said...am challanged by wires and setting things like this up.

Any and all advice is appreciated.

Thank you....

[COLOFIREMAN]

Not to beat a dead horse...but is there a dummy down intructional form that I can use to make this happen. I am wiring challenged.

My chero had...the trailblazer unit but the PO removed it for an aero 40 gallon main tank. I want to put the trailblazer back in and like I said...am challanged by wires and setting things like this up.

Any and all advice is appreciated.

Thank you....

No problem here you go, very easy. And with pictures both ways...........

This a "6-pin", meaning the back of the switch. This one works best in a newer truck.

http://i226.photobucket.com/albums/dd218/COLOJEEPGUY2K/senderdiagram.jpg
This is a "3-pin" meaning the same thing. This one works best in an older truck.

http://i226.photobucket.com/albums/dd218/COLOJEEPGUY2K/untitled-2.jpg