Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

making a custom fuel cell...

Discussion in 'The Garage' started by jekbrown, Sep 7, 2003.

  1. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

    Joined:
    May 19, 2001
    Posts:
    45,029
    Likes Received:
    362
    Location:
    Vancouver, WA, USA
    Im pondering my s-10 body swap and am thinking about using a custom fuel cell so it wont a) take up the entire rear end of the truck and b) wont get in the way of suspension stuff or c) be low enough to be a ground clearance problem. I am thinking that a tall/wide but relatively thin tank right behind the cab might do the trick. At any rate, the pre-made tanks i see at summit etc arent even close to the dimensions I am thinking off... and most pics I see of peoples bobbed/tubed rigs with these tanks installed.. the dang tank uses up the entire rear end of the truck. Not what I am lookin for.

    At any rate, the idea of making such a tank seems like the best approach. Is the making of fuel cells rocket science... or are sumps/baffles and all that jazz pretty simple to figure out? any info/pics appreciated,

    j
     
  2. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

    Joined:
    Dec 15, 2002
    Posts:
    15,139
    Likes Received:
    565
    Location:
    Iowa
    Don't have any pics for you but I have made a fuel cell in the past. The baffles and sumps are easy if you can weld aluminum. The reason I say aluminum is steel will rust inside and cause you grief so don't use it unless you line it with something. Best bet is aluminum. When you do your sump keep it just a tad off the bottom of the tank. I think summit sells peices that screw in to your sump so that you can place fuel pickups in different locations and don't suck air in to the system. This way you don't starve for fuel in an off camber situation. Baffles are simple. Put walls in the tank with half holes around the edges this will slow the sloshing. JC Whitney sells sending units that work with GM gauges. Don't forget a vent tube. Have fun.
     
  3. ntsqd

    ntsqd 1/2 ton status

    Joined:
    Nov 28, 2002
    Posts:
    3,381
    Likes Received:
    0
    Location:
    So. CA
    Fuel cell or fuel tank ? There is a big difference. Cells have either a rubber bladder filled with foam or (cheaper) a blown polyethylene 'tank' filled with foam.
    Fuel cells are aero-science, but not rocket science.

    For a tank like you're talking about wanting have a look at those fuel tanks made for boats. A friend got one from Overton's for use as a seccond tank in his 454 SS. He put it exactly where you're talking about putting yours. Can't recall capacity, but it was plus side of 10 gallons and probably more like 20 gallons.

    Some hints on making your own tank:
    231 cubic inches = 1 gallon. A Buick Grand National V6 displaces exactly one gallon.

    Don't suck right off the bottom of the tank, space the pick-up off the floor ~1/4" or so.

    For a tank like yours baffling can be done, but it won't fix everything. Sidehills will be the worst case scenario. Instead put a piece of 3"-4" OD muffler moly as near the center of the bottom as is reasonable. Make it about 6"-10" long. Cap the bottom and put a drain there. Extend your pick-up down into this.

    That foam in fuel cells is used to control slosh. You can buy it from JAZ and others. You don't need to fill the whole tank with it, when you fab the tank put in some tabs to hold the foam down & just put a layer across the bottom of the tank. It does age though and some blends of pump gas are particularly hard on it. Run a good filter and keep an eye out for particulates that are decomposing foam.
     
  4. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

    Joined:
    May 19, 2001
    Posts:
    45,029
    Likes Received:
    362
    Location:
    Vancouver, WA, USA
    clarification: fuel TANK is what Im looking to make, not a cell... i misunderstood the differences between them. thanks much for the info guys, I really appreciate it. I seem to remember a bobbed (both front and rear) Bronco that was in 4 wheeler a few years ago that had a tank like I am thinking of... it was maybe 4' wide, 2.5 to 3' tall, but only like 4-5" thick... sorta like thick radiator proportions. /forums/images/graemlins/wink.gif Im not sure how much room I will have between the various exo-skeleton tube at that location, but with respect to width and height there should be quite a bit. I want to maintain some storage space out back and its really gonna take optimization of everything I plan on putting back there to get all I that I can.

    anyway, thanks again. If anyone else had any tips, they'd be appreciated too. /forums/images/graemlins/grin.gif

    j
     
  5. jarheadk5

    jarheadk5 1/2 ton status

    Joined:
    Mar 6, 2000
    Posts:
    4,389
    Likes Received:
    0
    Location:
    PA
    Just remember that gasoline has mass and inertia when it sloshes. A tall tank could cause stability issues if you're sidehilling close to the rollover angle of the truck, you've got less than a full tank, and rocks/bumps in the trail are causing slosh. If I were building a tank similar to the one you described (4ft wide), I'd probably build in 4 or 5 vertical baffles to help prevent sloshing, and drill some 1/2" holes to help equalize fuel amounts in each compartment; maybe two holes for every 6" of baffle height. Do a half-circle at the basetop and bottom of each baffle so the bottom flow isn't obstructed and air can move between compartments, maybe 1" radius. Don't forget to allow expansion room in your filler neck, and keep it away from people in case of a rollover.
     
  6. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

    Joined:
    May 19, 2001
    Posts:
    45,029
    Likes Received:
    362
    Location:
    Vancouver, WA, USA
    lots of good tips jarhead, thanks much! Whats the deal with "expansion room in your filler neck" tho? Dont tanks just have breathers?

    AFA keeping it away from people.. with it so close to the cab, that will be a big priority. The back of the cab will be completely closed, and I also plan on the exo-skel to have some major vertical x-bracing between the cab and this tank that will be tied into the frame all over the place. Oughta be pretty beefy. Not sure how much more I could isolate it, maybe have breathers, filler necks etc lead further back to the rear?

    j
     
  7. jarheadk5

    jarheadk5 1/2 ton status

    Joined:
    Mar 6, 2000
    Posts:
    4,389
    Likes Received:
    0
    Location:
    PA
    As you know I'm sure, gasoline expands when heated. If you fill the tank completely and don't leave a little room (technical term: ullage ) for the gas to expand into, it'll build pressure in the tank and force it's way out of the breather, causing a fuel spill. /forums/images/graemlins/blush.gif Or down the carb if so equipped, causing an "interesting" first start... /forums/images/graemlins/angryfire.gif
    Don't forget that the fill cap has to be as high or a bit higher than the top of the tank, or it'll be impossible to fill without some sort of dry-break fitting - and I haven't seen one of those at the local gas station recently... /forums/images/graemlins/wink.gif
     
  8. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

    Joined:
    May 19, 2001
    Posts:
    45,029
    Likes Received:
    362
    Location:
    Vancouver, WA, USA
    oh ok, i see what you're saying. /forums/images/graemlins/grin.gif if the filler neck attaches to the tank at the top tho (like a stock tank i guess), how do you keep from filling it all the way and keep expansion due to heat from being a problem? not sure if i said that too clearly, lol, hopefully its somewhat understandable. /forums/images/graemlins/smile.gif

    j
     
  9. jarheadk5

    jarheadk5 1/2 ton status

    Joined:
    Mar 6, 2000
    Posts:
    4,389
    Likes Received:
    0
    Location:
    PA
    Totally understandable.

    OK, thought about it some more, if you fill at a gas station the pump should automatically kick off when the liquid level gets to the pump spout. If the pump spout extends, lets say 3" into the tank itself, then there shouldn't be any problems.
    Just thought of something else too: your tank breather line should have an inline check valve of some sort to help prevent a leak in the event of a rollover. Could be something as simple as a PCV valve rigged to be closed when inverted... Wouldn't be 100% leakproof, but it won't be a running stream of flammable liquid looking for a spark, either.
     
  10. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

    Joined:
    May 19, 2001
    Posts:
    45,029
    Likes Received:
    362
    Location:
    Vancouver, WA, USA
    good call on the filler neck... no reason why it has to be very long, and if its not, then the old auto-cut-off on the pump should work just fine. Thanks for the tip on the breather also, great idea!! Rolling a rig is annoying enough, I dont need to get cooked to death at the same time!

    j
     
  11. leadfoot067

    leadfoot067 1/2 ton status

    Joined:
    May 14, 2001
    Posts:
    1,563
    Likes Received:
    0
    Location:
    puyallup, washington
    you can buy the check valve specifically for a fuel tank .....summit has them...
     
  12. jarheadk5

    jarheadk5 1/2 ton status

    Joined:
    Mar 6, 2000
    Posts:
    4,389
    Likes Received:
    0
    Location:
    PA
    You're right. I was boresighted on the filler & vent issue and didn't think about the feed line. The valve from Summitt is for the feed line to the motor, though. Probably overkill for a tank vent line, but just dandy for the feed line.
     
  13. ntsqd

    ntsqd 1/2 ton status

    Joined:
    Nov 28, 2002
    Posts:
    3,381
    Likes Received:
    0
    Location:
    So. CA
    There is a valve made for the vent, they're called "Anti-tip over valves." Most fuel cell makers stock them. Careful routing of the vent hose will do 80% of the same thing. It should go up at an angle away from the tank, then go verticle, then horizontal across the vehicle, the down below the bottom of the tank. That way at least part of the vent hose is always above the fuel level in the tank no matter what the orientation of the vehicle is. It will also drain any fuel once the vehicle is righted. Beware of getting a low spot as that will act like the p-trap in a toilet and create a blockage.
    I always put one of those cheap VW plastic bodied fuel filters in the end of the hose to keep water & dirt from getting into the tank through the hose.
     
  14. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

    Joined:
    May 19, 2001
    Posts:
    45,029
    Likes Received:
    362
    Location:
    Vancouver, WA, USA
    cool beans, I like the idea of putting a little inline filter at the end... otherwise it seems like water crossings and mud could do a number on your vent tube. /forums/images/graemlins/smile.gif thanks much for the info guys! Once this thread is dead Im gonna print it off and put it in my 4x4 info notebook. /forums/images/graemlins/laugh.gif lots of usefull info to be had here, as always. /forums/images/graemlins/smile.gif anyone else have any tips for me while we're at it? If anyone had pics of a tank they made while they were making it (ie pics of the baffles, sump etc) that'd be awesome! /forums/images/graemlins/grin.gif /forums/images/graemlins/thumb.gif

    j
     

Share This Page