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M38-A1 gas tank 12V sending unit

Discussion in 'Early CJ5 and CJ6 Tech' started by tallyjeeper, Feb 18, 2005.

  1. Feb 18, 2005
    tallyjeeper

    tallyjeeper Member

    Tallahassee, Florida
    Joined:
    Jan 8, 2005
    Messages:
    134
    Howdy Gang!!!
    Does anyone out there in JEEPLAND know if it is possible to convert the stock 24V sending unit from a M38-A1 gas tank to 12V? If not, will a 12V sender from a cj5 bolt into a M38 go-go juice container? I would like to keep the large style filler neck of the military gas tanks, but run a 12V electrical system. I know that the M38 and M38-A1 share the same filler neck and gas cap, so either one would work as long as I could rig it with the 12V sender. The original tank from my jeep needs to be replaced, as it is rusted out, so any ideas on this topic will be appreciated and considered! :p

    Thanks,
    John
     
    tallyjeeper, Feb 18, 2005
    #1
  2. Feb 18, 2005
    scott milliner

    scott milliner Master Fabricator

    Seattle Wa.
    Joined:
    Dec 17, 2002
    Messages:
    2,362
    Use the stock sending unit and a new 12 volt fuel gauge.
     
    scott milliner, Feb 18, 2005
    #2
  3. Feb 18, 2005
    maxx

    maxx Banned

    Menlo Park, Ca
    Joined:
    Apr 22, 2003
    Messages:
    171
    M38 senders are opposite from Civilian jeeps. There may be a way to do it. Check Vernco.com under "electrical projects".
     
    maxx, Feb 18, 2005
    #3
  4. Feb 19, 2005
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
    Joined:
    Nov 6, 2002
    Messages:
    4,275
    The sending unit is simply a variable resistor. For a 24v to 12v conversion, you will need to change out the fuel gauge for a 12v unit. Make sure that the new gauge is designed for the same range of resistance as the sending unit, as there are several ranges.

    While you have the old tank out, put an ohmmeter across the sending unit and move the float from one end of its travel to the other. This will give you the range. Buy a guage that matches this range and you are good to go.

    <Edit> I forgot. You will have to bend the arm on the float to work in the opposite direction, since the military gauges worked opposite from the civilian ones as posted earlier.
     
    w3srl, Feb 19, 2005
    #4
  5. Feb 19, 2005
    tallyjeeper

    tallyjeeper Member

    Tallahassee, Florida
    Joined:
    Jan 8, 2005
    Messages:
    134
    Thanks for the tech, it will save me alot of headaches! I've seen several 24-12V conversions, but never thought to ask about the fuel system. :oops:
    John
     
    tallyjeeper, Feb 19, 2005
    #5
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