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M38a1 Fuel Pump?

Discussion in 'Early CJ5 and CJ6 Tech' started by colojeepguy, May 13, 2017.

  1. May 13, 2017
    colojeepguy

    colojeepguy Colorado Springs

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    Trying to piece together a Jeep that someone else took apart....does this look like the right fuel pump for an M38A1?

    20170513_101211.jpg 20170513_101201.jpg 20170513_100815.jpg

    The pump is cracked by the mounting ears, like it's the wrong pump and the force on the arm cracked the housing...
     
  2. May 13, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    An M38A1 fuel pump should have a hand primer handle/lever. It is obviously a dual action pump of course. The only thing you can really do is a side by side comparison for the cam contact arm angle with a known correct F/L head fuel pump.
     
  3. May 13, 2017
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Looks a lot like M38A1, but for the priming lever.

    [​IMG]
     
    Last edited: May 13, 2017
  4. May 13, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    I agree, looks quite similar. I looked at a spare fuel pump and the sweep of the arm doesn't appear to be as low as the one in question here. Hard to say for sure but my guess is either that is the wrong arm for that pump or just the wrong fuel pump.
     
  5. May 13, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    The double spacers also make it look like maybe someone "tried" to make it work?
     
    Bowbender likes this.
  6. May 13, 2017
    colojeepguy

    colojeepguy Colorado Springs

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    I think that's what happened.
    The Jeep belongs to a local museum, so I don't know what all has been done to it.
    We got it running with a single action pump with the glass filter bowl. Not correct for this vehicle, but it does run now. I'm not sure what the long range plans are for it... 20170513_135437.jpg 20170513_102008.jpg
     
  7. May 13, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Good looking A1, glad you were able to get it running. :)
     
  8. May 17, 2017
    bolerpuller

    bolerpuller Member

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    Sorry if this is a dumb question....but if they're both f-heads, are the fuel pumps interchangable between an m38a1 and a cj5?
     
  9. May 17, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Yes they are. He used a civilian fuel pump to get it running. ;)
     
  10. May 17, 2017
    colojeepguy

    colojeepguy Colorado Springs

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    What Glenn said.
    They are interchangeable as far as bolting to the block. Externally, quite different.
    This was the first time I had a chance to get up close and personal with an M38A1, & I was surprised by how different they are. Same basic vehicle, but a lot of difference in the details.
     
  11. May 18, 2017
    bolerpuller

    bolerpuller Member

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    The m38 pump looks competely different. If they're interchangeable is there an advantage to using one over the other?
     
  12. May 18, 2017
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I have no knowledge about the M38 per se. But keep in mind every item on the A1 was designed to be capable of operating underwater. That required both sealing and venting (=pressurizing) systems.
     
  13. May 18, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    M38 design was the same as the A1 as far as the systems, and the G741 (M37, M43 etc. series are designed the same. My M series fuel pumps are very similar looking to the A1 fuel pump, I would have thought the M38 would use the same fuel pump as the A1.
     
  14. May 18, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Midwest Military shows both the M38 and the M38A1 pumps and to me they look quite similar.
     
  15. May 18, 2017
    bolerpuller

    bolerpuller Member

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    Sorry. My bad. I droped the A1. Meant m38A1 not m38. The m38A1 pump looks twice the size to me. Is there a reason fo run a double action pump over a single? Isn't the cj5 pump water proof? Thanks!
     
  16. May 18, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    As far as I know the vacuum boost for the windshield wipers would be the main reason, just as double action for civilian vacuum wipers. Remember, military vehicles are built heavy duty when compared to the same vehicle in a civilian version. Basically the civilian single action fuel pump is wimpy compared to a military one. And yes of course it is water proof, otherwise it would leak. :)
     
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