Projects Help Me Decide on Fuel Tank Design - Model A Pickup

So, I've finally decided it's time to upgrade the fuel system on the ol' A, I'm still using the original tank in the cowl. Most fuel tank installations I've seen on trucks just put a simple cylindrical tank in the bed of the truck and let it gravity feed to a mechanical fuel pump on the engine. That would be the easiest thing to do, but I don't want to give up the bed space, cause I actually use this thing to haul stuff around. Not much, usually just some music gear (guitar amps, PA speakers, etc), but sometimes I use it to bring home bags of salt for the water softener, or bags of quikcrete for yard projects, or Christmas trees at Christmas time, whatever. I do use it. So no tank in the bed.

But I have room under the bed behind the rear axle. And after measuring it and searching all through the net I've come down to 3 basic options. Take that same cylindrical tank and hang it under the bed, or go with a commercially available aluminum tank I found online (the only 1 that is close to what I need), or build a tank to fit. I've done a lot of reading articles and forum threads from guys who have built tanks, and it's not beyond my skill level to do. I've got a friend at my Church that has a sheet metal fabrication business, and I already spoke to him, and he will cut and bend the metal for me.

So here are the 3 options (no, the drawing is not to scale, and not intended to be a perfect drawing, I just drew up quickly in Microsoft Draw last night to illustrate my ideas):


Pro's and con's:
Option 1, Pro - Tank is inexpensive, available, easy to install. 11 gal capacity. Con - Hangs real low, outlet at the bottom is exposed. Long way from bottom of tank back up to frame rail, I'm not sure an electric pump will pull the fuel up that far.

Option 2, Pro - Tank is a little more expensive, but not bad (~$200), it is available for shipment, easy installation. 12 gal capacity. Con - Tank hangs real low in back, no chance to tuck it up between rails, so 9" below rails. Outlet is on the top of the tank, electric fuel pump will have to pull fuel up to 9" when the tank is low on fuel.

Optoin 3, Pro - Best fit, will tuck up mostly out of the way and out of view from the rear. Possibly no electric pump will be needed? I'm not sure if the mechanical pump on the engine (SBC) will pull the fuel all the way. But if elect pump is needed, I could install it right down at the outlet level of the tank, so no pulling needed. Cost of materials is low (but will require assembly). 10.3 gal capacity. Con - Have to build the tank. Friend's shop is busy, backed up with work, will have to wait till his work load opens up, maybe not till Winter time.

 

Whatever tank you decide on, don't use a bottom outlet. Use a pickup tube into the tank from the top, or at least the upper-front. An electric pump can pull it up this amount, and a mechanical can as well. Most mechanical pumps since the beginning of fuel pumps have had to pull the fuel all the way from the back of the car, through the top of the tank, uphill to the carb.

 

Why not in the bed? I get what you are saying, but they never look right with a tank hanging down back there. Plus filling them is a pain if you have something in the bed. I am gravity feeding to an electric pump mounted to the bottom of the bed floor.

 

Properly functioning mechanical SBC pump will be sufficient for all 3 scenarios. No need for electric in the line.

 

Maybe take a look at 64-65 Mustang tank, my brother has one under the bed of his 29. Just have to get imaginative on the filler. His fills through the bed floor, could fill from outside the bed between tailgate and fender easy enough. Oh, and new tanks are very reasonable.

 

You would have to make some sort of extension to lengthen the frame but a deuce passenger gas tank would work well under the bed,you could make a access hole in the bed. HRP

 

I know it's not a A, an space is Paramount, I used a late 70's Jeep CJ tank in my 41 international, worked excellent, square tank, I mounted it backwards to get fuel fill on dr. Side fender, bent tubing from cheap cast aluminum marine flip cap, to tank couple hose's, didn't want the fuel fill in the bed, Just something I myself am not a fan of...

 

Just a thought, buy tank # 2, narrow it and fit it like # 3 . A mechanical pump would and has worked just fine in a set-up like that.

 

I'd take a picture of my tank but my truck box is full of junk...yep I use mine. I built a tank. It's about 5" tall, about 30?" Wide (the width of the frame rails) and 18" long. It sits just above my frame rails in front of the differential and at only 5" tall, it sits just below the bed (except for the fuel cap). I had a local shop shear and brake the pieces and I welded it all together. I also put a couple baffles inside of it. The suction is on the top. It holds a total of around 9-10 gallons.

 

Build it man.
If you got a guy who can cut n bend and you have the skills to weld it all up then go for it.
And if you are building then I guess you could go in tank pump..
Most fuel pumps like being below the pick up tube so there is less stress on them.

If you your mate has a cnc cutter at his shop then go whole hog and design it up and get it cut. that way you will have all the holes in place, baffles cut to fit just right etc.

I will be laser cutting and tig welding up mine.
Scroll down the build thread below. A young kiwi guy building a 51 Chev Pickup. You will see his tank he built up. laid out flat after cutting, his baffles & then welded up. might give you ideas.
https://oldschool.co.nz/index.php?/topic/47316-matts-1951-chevy-pickup/&page=3

 

I used a Mazda E2000 tank.
About 11 7/8 x 11 7/8 x 34.
I dont remember the exact measurements in my head right now.

 

One problem I see if you mount pump in tank , if you need to repair pump,leak(gasket) or wiring you have to drop tank (if full of fuel) = more work. Electric pump on frame or mechanical on engine easier to work on , get to (no need to drop tank). If you are away from home , raining , cold , snow or whatever , what scenario do you want, changing out an electric/mechanical pump or tow $,parts $ and labor$. Just an idea.

 

Thanks for all the responses. I'm encouraged by those that say the mechanical pump on the engine will pull the fuel, I don't know why but I assumed there would be an issue with that, and was looking to add an electric pump to pus the fuel up to the mechanical pump. My pump is good, around 1 year old, so not many miles on it, and it supplies good pressure.

Seems like I could modify the round tank in option 1 to add a pickup tube exiting from the top/front part of the tank, with an internal tube running down to the lowest point. So that's another option.

Another con about that tank though is I don't believe it is baffled, so once the fuel level is low the pickup tube could easily become uncovered during acceleration or cornering, or braking. Though the shape of the tank encourages rapid return to the bottom.

I think I'll make up some cardboard versions of these tanks and see how they look sitting under the bed.

 

That is an awesome build thread, that guy has mad skills!

 

Too wide, and too long. And it would hang down pretty far too. Just not right for this application. Thanks for the suggestion though.

 

So I mocked up some tanks to get a visual of how they would fit in place, and of course Option 3, the custom tank, will fit the best, but Option 1 is not bad at all either. Option 3 is just too bulky, not a good fit, and too visible from the rear and side.

Here's the top view of the 3 tanks:



View from underneath:





Side/rear view:
Option 1

Option 2

Option 3


All considered, #3 tucks up the nicest, out of the way, least visible; but the difference between that and #1 is pretty slight, and neither of them is enough to be obtrusive IMO. I think a stainless cylinder tank may be visible from the back, but in a good way. While #1 may be best, the wait time to get the materials bent up, and then the labor time if I build it myself; or the cost if I order up a custom tank, don't seem to be worth it to me. Plus, #1 will be the easiest to install by far. I think I'm gonna order one of the cylinder tanks and get it installed.

 

I like the cardboard mock up. It makes all the difference in the world to actually try and fit it in. You see stuff you wouldn't catch otherwise.
Option 1 or 3. Only 2 if you paint it to match body color. My dad did a stainless tank on his 36 p/u that is similar to option 2 and I stare at it every time I walk behind it. It bothers me.

 

I think the decision is not obvious (pardon the pun) option 3 . We put a large capacity tank in our 32 and it looks like its got a full diaper.

 

Your truck rules.

 

Why? None of the options are going to give you a lot more capacity than the original. Is there a problem with your original? You say youre using it, but no problems. Henry had a good idea. And the fuel gauge looks so damned cool in the dash!

 

A couple of reasons. 1, It always smells of gasoline in the cab, even though there's no seepage that I can see, still it reeks. It doesn't bother me so much, but it does bother the wifey. 2, The fill neck has been damaged so that the cap doesn't seal well, so when the tank is full it will leak out around the cap when the fuel sloshes. When I finally do get the paint work done, I don't want gas leaking out of the cap. And in the event of a turn over this makes the likelihood of a fire much greater. I could repair the fill neck, but all things considered I'd rather install a new tank. 3, Racing associations don't want fuel tanks in the passenger compartment. I can't take it out on most tracks using the stock tank. And that is something that I want to do.

 

Blues, I used your 3rd option, like you say tucked away and uses all the space to guarantee decent capacity.
I got about 16 US gallons or 65 litres and put a bit of a roll pan at the rear to kind of hide the part hanging down and pretty it up.
Mines a 26 T pickup on a 32 style chassis.
Function and form will decided in the end...

 

231 cubic inches in a gallon, and I have no idea why I still remember that number after 40 years.

 

Yep. The formula for calculating the volume of a tank in gals is: L x W x H / 231.

For a cylinder type tank, it's D squared x .785 x L / 231.

 

I build at tank to go between the frame rails of my '29 rpu, right behind the cab. The filler will be under a door in the bed floor.

 

Go to tanks.com and see what they have. The tank I got was made for my car, but, they had several different styles, with measurements. Their prices were not bad at all either. You may find something like the mustang tank that will fit, with a little more capacity. I have friends that have used vw bug or type 3 tanks for their hot rod projects. Something else you might consider.

 

That's nice. I could move the battery to the back and mount one as you have. Hadn't thought of that, thanks!

 

I know you don't want it in the bed but thought I'd share my solution anyway.

 

Just type in to the ebay search function "aluminum gas tank RCI" and select category ebay motors and you will find numerous gas tanks on offer already made in various shapes and capacities.
For what you get they are darn cheap in my book if you can score a size that works for you.
I got two here sitting at home ready for future projects at those prices...

 

Seems to me that you have one side where you will not be able to suck up all the petrol. That step up over the drive shaft makes a reservoir your pump wont be able to draw from. Looks a bit tight - whats the clearances like should you blow a tire/scrub line. Diff & suspension wont hit?