Building a Fuel Cell

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Doing some future planning here ....

Looking at building a fuel tank for my 40 out of 1/8" aluminum. The plan is not move the rear axle back and put the tank under the floorboard behind the two frame crossmembers (between the xfer and rear axle). It will be fairly flat and wide with a steel plate under it to protect it from whatever. Gonna tig it all together and put baffles in the tank as well. Gonna run an Autometer sending unit so the tank will need to be at least 5 inches deep.

I don't much car for the under-seat tanks and since I lowered the passenger seat I cain't put one there anyway.

Eventually I'll go with fuel injection. Do I just need a return line for the EFI? Anything else I need to consider for this project.

Thanks, Mike
 

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Vent...




Good luck!


-Steve
 

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Yup. Need a return line and a vent. It would be worth it to include at least two bungs for those and maybe a thrid for who knows what down the line. How hard is it to just have an extra?

Baffle it up well. Woodrow managed to stall his EFI because he sucked his foam dry on an extreme angle a couple of weeks ago.

If you are planning on running a GM FI, it might be worth the effort to build in a GM style sending unit/ pump assembly. It would also be worth making an access panel to this assembly so you can service it without dropping the tank. The GM pumps are reliable, cheap and are at the correct pressures. They cool from the fuel, so they work well in wheeling situations where other external pumps may get hot.
 
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Picked up the aluminum today, .125" T6. Gonna mock up the tank out of cardboard today. Should be able to get at least a 2" deep sump, hopfully 8"x8" in center of the tank. Gotta figure out the filler neck now too.

Should I go ahead and put the GM in-tank pump in now, knowing it may be a while before I get the EFI installed?

How large would yall make the access hatch? Recommendations on any bling-bling fasteners to secure the hatch?

Thanks,
Mike
 
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66fj40x2 said:
Pics? Just to get an idea abot how big to make it. I'd think a sump would best centered in the tank too???

I would say back of tank but thats just an opinion. Need engine power to go up not down. Or just keep her filled and you won't have an issue :)
 
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I'll try and get a pic for you later today when I'm on my laptop as for the sump its 2" centered i want to say its 6" wide with 6" on either side of it. The line out and return come out of it. Which direction you face the sump is up to you. When I first put my tank in I faced the sump to the back. This would help with getting the most fuel to the line except on extreme downhills but then you dont need gas you've got gravity. Although I havent been going down a hill that steep anyway. Since then I remounted the tank though in order to get more room in the bed area of the 55. So the sump now faces the center of the cruiser.
 
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Finally started on this project .... I've basically taken the measurments off my NWMP rear mounted tank and made it a little shorter for better ground clearance and adding a sump and took about 3.5" off the front for axle clearance. The sump will have outlets front and rear so hills shouldn't be an issue. Vent and return lines on top of tank. Planning on adding a second rear frame crossmember to mount it to in the front.

Questions:

Do I need to add baffles to the tank?
If so, what is the best way to do it? Foam?
Do I need to coat the inside of the tank (T6 aluminum) with anything?
On Summit's sumped tanks there are two outlet fittings, why?

I should have pics of the cut aluminum mostly mocked up later today.

Does anyone near Tyler, TX have any contacts at Racers Choice, Inc. (RCI)

Thank You for all the help!
 
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Sorry I never posted a pic the tank is in the cruiser so you can't really see it worth a darn. The tank has an outlet a return and a vent on top. I have foam in mine came in it. I have heard just to pull it I am going to leave it in and see if it degrades as stated. I have a clear in line filter so I can see if it is going into the line.
 
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make sure you flange all of your corners, we are pretty fond of a double clamshell layout, but that's mostly to get nice fillet welds everywhere. most important to a tank is how you mount it, try to get it as loose as possible, ie the factory strap system that just supports the tank without restraining it. returns are also below the surface of the fuel if you expect a lot of return flow but otherwise it can be returned to the top of the tank, below surface is to prevent any air from getting mixed in with the fuel, a small engine like that shouldn't need it though. I would leave out the foam, just think about your baffle design. run them from side to side maybe in front of and behind your sump, to keep sloshing fuel mostly maintained in the sump area. the holes in the baffle really only need to flow a little more than your fuel pump pulls.
 

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I'd use only 316 Stainless steel for any fasteners on the tank, otherwise you will likely get corrosion issuses (galvanic corrosion from dissimilar metals) 316 stainless is pretty close to neutral on the galvanic scale.

As for welds not being able to stand the pressure and cracking, I don't believe that, those welds were done too hot.
 
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FoYoChe - I'm not the welder so please explain the flanged corner and double clamshell layout.

The tank will actually sit on the steel skid plate. The skid plate will be bolted to the crossmembers. I plan on using POR15 on the bottom of the tank and the skid plate to insulate the dis-similar metals.

Miles - I'll let ya know as soon as I figure out what this one is gonna run me :D
 
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