Adding a gas tank on a 40 without having to add a separate filler cap? (1 Viewer)

[Ride Fly]

What are the options out there?

I'm thinking about future changes to my soon-to-be 40, and I was thinking of adding an extra tank. However, I don't want to cut a hole in the rear panel to add the extra filler cap. I would want to avoid that at all cost, so I started thinking if it would be possible to add a tank directly under the existing tank so as to avoid cutting a hole in the rear. If it hasn't been done before, it's something I think should be developed. Maybe welding or bolting directly under the existing tank and adding some sort fuel pipe/transfer system so that it's automatic, not requiring you to manually switch over when the first tank runs dry.

 

[jfz80]

option 1.... put down the pipe

what year is your said soon to be 40? gas tank under the seat sits on the floor in most, so your plan is to go through floor and reduce ground clearance? Id think even on a street rig this wouldnt be ideal... even if just for aesthetics

A larger main may work better for you
S-10 tanks have been a popular one for fit

SOR makes a tank that goes to the rear.... seems feasible enough to run it solo or has it perform as a transfer tank but still leaves you the task of adding of filler tube
Page 250 Land Cruiser Auxiliary Fuel Tank

 

[Michael B]

You can replace the inside tank with a larger unit. It will be under both seats and use the existing filler neck. Assuming your soon to be 40 is 78' or older.

 

[Ride Fly]

option 1.... put down the pipe

what year is your said soon to be 40? gas tank under the seat sits on the floor in most, so your plan is to go through floor and reduce ground clearance? Id think even on a street rig this wouldnt be ideal... even if just for aesthetics

A larger main may work better for you
S-10 tanks have been a popular one for fit

SOR makes a tank that goes to the rear.... seems feasible enough to run it solo or has it perform as a transfer tank but still leaves you the task of adding of filler tube
Page 250 Land Cruiser Auxiliary Fuel Tank

I can dream, can't I???

Mine is a 77. Finalizing the transaction in a day or two, and will need to ship from Delray Beach, FL.

IIUC, didn't the very early 40s have tanks under the body, directly under the passenger side seat? Back when I first starting looking at buying a 40, a seller of a '72 FJ stated the tank was "moved" to under the passenger seat for better ground clearance. I took that as to imply that at some point, the tank was outside the tub, maybe even under the passsenger seat.

Anyways, what is the concensus here about the extra tank? Leave it original or add? Or replace with the larger capacity tank?

Thanks!

 

[Rock40]

In it's original position, the tank on a 72' would be inside the cab, under the passenger seat.

If it was me, I'd just run the stock tank and be happy with it. Adding a second tank without a filler neck is likely to end up hokey and carrying a spare fuel can will be easier and so much cleaner.

As for the "long ranger" tank that goes under both the front passenger and driver side seats (inside the cab), I have found that to be one of the worst designed tanks out there. I bought a used one on CL years ago and was super excited to get it installed. Oh wait, you have to modify the floor pan to get it to fit right (I have a 69') and the baffling is woefully inadequate. If I take a corner with less than 1/2 a tank of fuel, it'll lose suction and I have tried everything to remedy that issue at this point. For the outrageous price tag, stay away.

 

[Downey]

Since your spare tire is on the drivers side on your 1977, you could run my 22 gallon rear fuel cell under the body (behind the rear axle), then run a filler neck out the back side (above the emblems) instead of out the side of the body.

 

[TheHardWay]

Since your spare tire is on the drivers side on your 1977, you could run my 22 gallon rear fuel cell under the body (behind the rear axle), then run a filler neck out the back side (above the emblems) instead of out the side of the body.

Huh? You got a photo or link for this setup?

 

[cruiserkev]

A Jerry can or two is a better option in my opinion. Mine has saved me and a few other wheelers over the years when you're low on gas in the middle of nowhere. ​

 

[Downey]

Huh? You got a photo or link for this setup?

Check out ebay #253347498138, but Mud members do not have to buy on ebay, I can just send you a paypal invoice, plus save you 50 bucks since I won't have to give it to ebay- - -easy deal.

 

[Ride Fly]

In it's original position, the tank on a 72' would be inside the cab, under the passenger seat.

If it was me, I'd just run the stock tank and be happy with it. Adding a second tank without a filler neck is likely to end up hokey and carrying a spare fuel can will be easier and so much cleaner.

As for the "long ranger" tank that goes under both the front passenger and driver side seats (inside the cab), I have found that to be one of the worst designed tanks out there. I bought a used one on CL years ago and was super excited to get it installed. Oh wait, you have to modify the floor pan to get it to fit right (I have a 69') and the baffling is woefully inadequate. If I take a corner with less than 1/2 a tank of fuel, it'll lose suction and I have tried everything to remedy that issue at this point. For the outrageous price tag, stay away.

Great gouge! Thanks for the warning!!

 

[Ride Fly]

Check out ebay #253347498138, but Mud members do not have to buy on ebay, I can just send you a paypal invoice, plus save you 50 bucks since I won't have to give it to ebay- - -easy deal.

Pretty cool design Downey! Got any pics of the installed product and how the filler cap looks? Also, how is the fuel switched from the main tank to the spare tank when empty- automatically or manually toggled? Does the fuel route from spare to main or directly motor? Thanks.

 

[Nader]

I've just been wrestling with my dual tank setup. Similar to Downey's, but not as nice. The filler neck goes through the rear passenger wheel well. When I bought the truck and had it truck flat-towed to my house, that wheel had a flat and shredded on the highway, taking the filler neck out with it. It was a real mess, also further bending the already rotten sheet metal in that fender. Picture in the well shows how the filler was hanging on by the literal thread, the rubber sleeve attaching it to the tank was shredded. When I replace that fender with fresh metal, I'm going to relocate the filler neck out the back, and shield whatever may still be exposed in the well.

 

[Nader]

As for how to connect two tanks with one filler; much of the problem stems from the two tanks being at unequal heights. I think it will take some creative plumbing and fuel pumping between the two, including giving thought to how the return fuel from the carb will be routed (which tank will get it?).

You can read how I dealt with the return line problem and issue in my own stumbling rolling "restoration" thread. The link below should jump you to the right page, but you'll need to scroll down to that fuel routing topic:
New here, no idea where to start.

 

[Living in the Past]

You can replace the inside tank with a larger unit. It will be under both seats and use the existing filler neck. Assuming your soon to be 40 is 78' or older.

Not sure if they changed the design but I knew someone who installed one of the Man-A-Fre's under the seats long range tanks in his FJ45LP-B. He complained of the noise of the gas slushing around because of the lack of baffles.

While routing would be a issue the FJ25 and 61 FJ40 used a large fill neck and gas cap. While I've never seen one believe the 80 series sub tank uses the same fill neck. If a guy was creative he could make a dual fill neck in the large opening using two fill necks from autos in the seventies and eighties that had a small opening to prevent leaded gas from being used. These had a spring loaded door which would help gas from migrated between tanks. Tee the vents together. Big problem is routing the fill line to the tank in the back which is the best place for a second tank in a FJ40. Thru the floor and along the inside of the frame might work. Inside the wheel well would create issues with tire rub. V8s with dual exhaust would create a problem with inside the frame. Not a fan of exhaust running by a fuel line of any type.

 

[brooklyn]

Auxiliary Fuel tank filler neck alternative

Picture of tank fill in back of FJ40

 

[Jdarkhark]

Dang that tank is perfect! Message inbound @Downey

 

[Vulcan]

Reviving an old thread... what about this solution: dual FJ40 tanks, one filler neck! One filler door with a modified fuel filler travelling to both stock and aux tanks. Would this interfere with seats/roll cage? Can this be done safely and cleanly (I've asked that OP for more pics).

Why can't you use the stock gas tank like a fuel reservoir? Since it sits higher, could you just run a line from stock tank drain (maybe widened) to aux tank that is gravity fed, then have fuel sent from aux tank to carb? So stock tank just holds gas and feeds the aux tank. Return could go to stock tank and flow by gravity back to aux tank.

I know NOTHING about gas tanks, so please don't stone me as I'm sure there are good reasons this can't be. But I too would love a solution for long trips without having to pull over and fill on the side of the interstate in the snow or have two filler doors.

 

[Downey]

Vulcan, possible problem with your gravity feed idea is: If higher front tank is gravity feeding into lower rear tank (without an open/closed shut off valve) front fuel will not only keep the rear tank topped off for awhile, but fuel will also spill out the filler neck, which I believe is also lower than the front tank- - -unless you run rear tank almost completely dry before gravity feeding front tank to rear. Also, if gravity feed fuel has to go through emissions plumbing, it will gravity feed too slow, and your rear tank will run out of fuel before all of the front fuel has gotten to rear tank.

 

[rkymtnflyfisher]

Carry a full tank under the seat, when you run low fill it back up with the extra fuel cans from the back. If I’m going somewhere that I know I’ll pass the gas station I opt for the cooler, if I’m going way back in the mountains I’ll carry almost a full tank of extra gas.

 

[cruiserkev]

Carry a full tank under the seat, when you run low fill it back up with the extra fuel cans from the back. If I’m going somewhere that I know I’ll pass the gas station I opt for the cooler, if I’m going way back in the mountains I’ll carry almost a full tank of extra gas.

View attachment 1792294

I agree, carry as much fuel as you can in the mountains. I have an old USMC jerry can that has been mounted on my 40 since the late 90's plus if needed, a 6 gallon plastic can as well for a combined 11 extra gallons. Haven't ever needed more fuel than that to date.

I have toyed with the idea of adding an extra tank but came to the realization that it's much harder to give your wheeling buddies a little gas on the trails with a permanently mounted tank. Plus I do enjoy making them fill the can back up when we reach civilization.

Learned to carry extra fuel the hard way back in '93 even before I had my cruiser. My buddy Tom and I drove his 78 FJ40 to the Lalapalooza concert at the Gorge in George WA. It got out really late and we could find no gas stations open at that hour. We were on fumes and just barely made it to the top of White pass around 3am. Had to coast 42 miles downhill to Packwood WA and had just enough inertia to make it to the cabin we were staying at. Luck was with us that night!

Lesson learned, Cruisers are gas pigs. Always carry a little extra just in case.