Secondary Fuel Tank

[gimpyrobb]

While that would work well, I'd never do it on a deuce.

 

[joshs1ofakindxj]

Amps are amps, the voltage across an unblown fuse is zero, so a ten amp fuse is a ten amp fuse is a ten amp fuse on 24v, 12v or 6v. The only time voltage rating comes into play is if the voltage is high enough to overcome the fuse housings dielectric rating. Since you are probably not installing a 30,000 volt alternator, not to worry.

I thought the fuse blew at a given amperage because of internal resistance, which would then fall under V=IR, but I'm a mechanical engineer, far from an electrical!

Edit: not that I didn't believe you, but more evidence to support you here: http://auto.howstuffworks.com/wfc2.htm

Most Over the Road trucks with multiple tanks, just use about a 3/4" transfer hose that is plumbed to the bottom side of the tanks. Both tanks stay the same level. It wouldn't matter which tank, the return is to. No extra wiring. Solder in a fitting on your new tank, with an outlet ball valve, pump off the fuel in you old tank, to the new one, while you solder in the fittings, then hook up a transfer hose, between the two tanks.

I also thought about that but from an off-roading perspective you have two problems: a low hanging fuel line that could get ripped off and empty both your tanks, secondly, on a slope the fuel will all go to the down hill tank. With two full tanks it would start pouring out the tank cap.

 

[73m819]

Still, the most KISS way is to draw/return from ONE thank, TRANSFER to that tank as needed from the other tank, this is how the m51a2s, m52a2s, 543a2s do it, a very simple set up, NO change over valves, ect. One switch (the 5t switch and plate) on the dash, in this case, it would switch gages and when set to the LEFT tank, it would switch on the left INTANK pump, VERY simple in wiring and plumbing (one line between tanks, no need for extra vent lines)

Just REMEMBER the simpler it is, the least that can go wrong down the road at the WORSE TIME

 

[gimpyrobb]

secondly, on a slope the fuel will all go to the down hill tank. With two full tanks it would start pouring out the tank cap.

Maybe not. I know someone that had his truck, "fuel tank down" and nothing leaked out.

 

[rmgill]

I have done this on my deuce.

I had a second fuel tank that I cleaned out completely and found some new hangers. My method was to use a supply/return valve from an M818 and mount it in the correct place left side of the driver on the floor. I added a second fuel gauge to monitor both tanks AND fuel pump selection is controlled by a switch on the dash that throws a relay, if things fail the right side tank gets power no matter what. The connections run from the tanks to the 3 way valve via some standard copper tubes/brass fittings to barb fittings and rubber hoses connecting to the valve thence back to the standard fuel supply lines on the right side rail to the primary filter. The relay box was installed up under the bed right side above the right side fuel tank. That allowed me to avoid cutting the existing system and if worse came to worse, I could run the wires back to the fuel pump bypassing the relay box.

It's basically designed to allow returning the whole thing to stock.

 

[rmgill]

See this post, there's a full writeup earlier in the thread.

Rough details of what I had to do in order to make this work.

1. Source a second tank with pump.
2. Source a set of fuel tank hangers.
3. Find a fuel selector valve from an M818 or other 5 ton with 2 tanks.
4. Find a relay and switch
5. find a second fuel tank level gauge.
6. source misc hardware, hoses, fittings copper line, and nuts/bolts for the setup

1st step, take down the spare tire hanger and loosen hardware on the inside of the frame rails where the hoses and wiring are so you don't cut them when drilling.
2nd, mark the hangers and center punch then drill the holes.
3rd, hang the fuel tank hangers and tank.
4th Fab up a new vent line and tee it into the existing vent line. If you split your vents before you should have an input already. This is iirc, 1/16's line (small stuff).
5th install the fuel valve after attaching all the usual hoses.
6th install the fuel gauge in the spot to the left of the existing gauge, add a one way switch on the dash to control the relay.
7. install the relay in a useful spot. I elected to install an aluminum box on the bed near the existing tank so I didn't have to hack the wiring hardness to find the correct wire. This way power runs to the tank but is diverted to go to the box with the relay control wire from the dash energizing the relay to select the left side pump. I'll otherwise power the right side pump when the relay coil is unenergized. Thus it fails to using the right side tank if there's a relay or switch problem.
8. plumb up the tank and fuel lines to the fuel selector valve.
9. test it and now you have 110 gallons of fuel good for ~1000 miles on a good day.

As I said later, the valve was the most expensive part. But it's the best way to do it in my mind as it avoids the problem of tank to tank transfer and adds redundancy to the fuel system that is present if you build a cascading transfer system.

 

[RedbeardTheZombieHunter]

Most Over the Road trucks with multiple tanks, just use about a 3/4" transfer hose that is plumbed to the bottom side of the tanks. Both tanks stay the same level. It wouldn't matter which tank, the return is to. No extra wiring. Solder in a fitting on your new tank, with an outlet ball valve, pump off the fuel in you old tank, to the new one, while you solder in the fittings, then hook up a transfer hose, between the two tanks.

I get ya, instead of isolating the two tanks, Link them with transfer hoses top and bottom. When the tanks are full, you got 100 gallons (per 50 gallon M35A2 tanks) and when the gauge reads half full, you got 50 gallons. This is the epitome of the K.I.S.S. principal. Makes sense to me!

 

[73m819]

I get ya, instead of isolating the two tanks, Link them with transfer hoses top and bottom. When the tanks are full, you got 100 gallons (per 50 gallon M35A2 tanks) and when the gauge reads half full, you got 50 gallons. This is the epitome of the K.I.S.S. principal. Makes sense to me!

Does not work for off road, the lower hose gets ripped off, so KISS does NOT work here

 

[gimpyrobb]

While its good to see others idears, I'm pretty sure Josh has a good plan and it is one of the best ones for the application. I hope he takes pics to update the thread so others may learn another way to do it.

 

[joshs1ofakindxj]

I'll be working on it this coming weekend hopefully. Pictures and instructions will follow.

I have a master cylinder and air pack to rebuild and install first. What good are dual fuel tanks if you can't stop?

 

[gimpyrobb]

Grandpa always said "You don't have to go, but you HAVE to stop!".

 

[TacticalDoc]

why not just buy a used transfer tank and put it in the back? I picked up a used 90 gal transfer tank with pump ant put it in the back.

Or, if you really want to KIS get a 50 gal drum and pump.

 

[gimpyrobb]

Personally, I would rather keep my bed open from clutter. More space for parts you can bring home from the rallys!

 

[joshs1ofakindxj]

I want a smooth look, and as much room in the bed as possible. I'm excited to work on it this weekend! I might even skip going to the bar!

 

[TacticalDoc]

Personally, I would rather keep my bed open from clutter. More space for parts you can bring home from the rallys!

The transfer tank I have is L shaped and takes up about 2 ft wide. If I need more room I'll take my M105.

If you still want more room I guess you could mount it to the top of your bed in front and rest it on the cab.


ii

 

[A/C Cages]

Grant installed a spare tank on the pioneer rack side of my bobber and it will transfer the fuel from that tank to the primary one with a flip of the switch. Whats good about this is I can keep clean Diesel in that spare tank and also use it for generator, welder, ect ect and keep my original tank as the multifuel tank.

 

[gimpyrobb]

Originally, I wanted a custom fuel tank to fit in the space between the bed and the truck frame. After looking around for something that would fit AND that I could afford, I went with a 100gal tank that will sit in my truck bed. I really struggle with having one built but that money can be better used elsewhere.

 

[simp5782]

I picked up the black tank from Vintage Iron for a decent price. 74 gal? 54 tank Going to mount it in place of my toolbox in picture 2. I will run them to a ford fuel selector valve (40$) + switch(10$) and have a 148gal fuel capacity. I just don't know about the clearance issue between the 16.00 and the tank. it looks close, but I dont think it will hurt anything. Might have to install a mud guard between them. My flatbed 3/8" steel plate will be as wide as the truck from the back side of the fuel cap lid all the way across to the same on the other side and the same length as the tank front to rear. then I will go down the bed with a 2'6" wide 3/8 plate and 4' long back to the gooseneck plate. i will have a tractor weight mount on the plate over the front axle so i can add and deduct the weights as needed.

 

[A/C Cages]

Very nice set up there Simp5782
Nice until you are at the fuel pump filling it up. lol

 

[simp5782]

Yeah tell me about it. I dread filling up my F-250 for long trips. 19gal front tank, 38 gallon rear and a 105L shape in the bed. $600 worth on it. Well I live about 30miles from a gas station right now. Plus we are planning on moving to TN in a few months. So it will help on the long trip so maybe I can pickup cheaper fuel prices. Cause I honestly dont think she will notice the difference in extra weight of 74 gallons more. Plus if I am in Memphis I might do some hurricane relief help and the extra fuel capacity will help. Unlike the posts I read bout that stuff and guys filling up every jerry can they can find.

I designed this for my transfer tank. to hold jerry cans on top. secured on each end by a pipe that goes thru the handles, then thru steel plates welded on the tank and locked on the outside of the plates. So noone can steal them very easy and they shudnt rattle away.

Tank is 60 inches wide. take away 10 inches for the pump turned sideways and the filler port. So 50" divided by 7" wide jerry cans will give me 7 cans maybe 8 depending on the amount of room i have. That is 74+74+105+35 = break the bank but a lot of fuel when you cant get any.

I wish I the "save at the pump when you buy groceries thing" was more than the 35gallons they let you have here. Save up and FILL UP. Id kill for $1.50 a gallon!

Sorry I got carried away. and NOONE make fun of my drawing. I had just a little to much caffeine tonight!