Home Forum Ask A Member 1937 Sea King / Thor 2.4 hp Water Pump

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  • #9561
    Buccaneer
    Participant

      US Member

      I’m cleaning up parts and looking over the water pump.
      There’s a fitting (above the cam shaft driven piston)
      with a check ball on top that the discharge
      line attaches to. Below the piston there’s another
      pipe thread in the housing that I’m assuming should have
      a screened fitting with a check ball inside that would
      be the "intake" of the water pump.
      Looking at my photos before and after disassembly,
      I see no such part.
      Anybody have any good ideas on making such a check valve
      with screen, if that’s indeed what I need?


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      #73489
      fifty20ne
      Participant

        US Member

        Yes it is simple ball check valve made from 9/16" brass hex stock.
        The OAL length is 1 9/16" long.
        The through hole I.D. above the ball is .35" This does not go all the way to the bottom, but provides the taper for the ball to rest on (shut off)
        The hole size under the ball is not kown? but should be smaller than the ball O.D. maybe 3/4 size of ball O.D. This hole connects to the six inlet holes.
        The Ball Diameter is 3/16 – 1/4 " aprox?
        The cross pin is close to a #35 drill size made from brasss rod pinned or staked to prevent movement. (You could also solder or braze)
        Location is .620" down from the top (thread side)
        The water inlet are six holes drilled on each side of hex a # 39 drill is a good fit, hole location 1.35" from top (thread side)
        Thread size is 1/2 X 18" check your motor to be sure .50" length.
        There is no cover screen on mine!


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        #73490
        Buccaneer
        Participant

          US Member

          Fifty20One, thanks for the detailed information and photos
          on the pump inlet check valve.
          If I’m thinking correctly, the inlet and outlet check valves
          would have to be designed differently, so the inlet ball
          seats on the pressure stroke of the piston, and the outlet
          ball opens. Correct?
          Wonder why they drilled six holes instead of
          just a screen on the bottom? Cheaper, and quicker
          I suppose.
          Thanks!

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          #73494
          fifty20ne
          Participant

            US Member

            Hi Buccanneer,

            Yes this water pump design uses two check balls (Valves) Upper and lower
            The hole size under the ball in the upper check valve is close to a #14 drill
            Remove your water line and you will see the upper check valve if you have
            Not done so already.
            The upper check valve closes (seats in the closed postion same as the lower)
            In other words the upper is the same design minus the intake holes. The cross pin is facing up.
            See Pics below.
            The upper check valve has been error proofed at the factory with fine threads at top and
            course threads on the bottom. both check valves are closed (Shut off) in the down position.
            I wonder who gets credit for error proofing this upper check valve?
            Was it Thornwald Hansen president of Thor or
            Elmer "Carl" Kiekhaefer?
            Yes I think they did not use a screen for two reasons!
            1) cheaper to manufacture (less parts & labor to install)
            2) less prone to clogging and easier to clean if clogged with mud debris etc..


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            #73498
            Buccaneer
            Participant

              US Member

              If both check valves were the same (minus the intake holes)
              wouldn’t both valves open the same time when the piston strokes?
              I probably have fuzzy logic on this, but if I’m going to make a check
              valve for the intake, I’d like to get it right the first time. 😮
              Thanks.

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              #73533
              fifty20ne
              Participant

                US Member

                This should explain piston pumps in more detail.

                https://www.globalspec.com/learnmore/fl … nger_pumps


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                #73549
                Buccaneer
                Participant

                  US Member

                  I made an inlet check valve today with a brass fitting,
                  steel ball. Used a couple of drill bits to make the
                  seat area, then lightly peened the ball into the seat
                  to help make a better seat. I then pinned the ball
                  inside the fitting with thin brass rod.
                  I only had one size / weight ball to work with,
                  so not sure if it’s sized right for the discharge check.
                  I "hope" it will work!

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