Home Forum Ask A Member Testing coils, per1938 Bendix Scintilla procedure

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  • #283082
    Buccaneer
    Participant

      US Member

      I’d like to test the Bendix TMD coils per the 1938 shop manual.
      The diagram says to use a “Standard Ford Coil”, and to “short out”
      the secondary.
      Do you suppose they’re talking about a Ford Model T coil, or 
      a standard automotive 6v Ford coil per 1938?

      What is the resulting difference if one runs the 6V directly to the Bendix
      coil’s primary, or go thru a Ford coil’s primary first, then to the Bendix
      coil’s primary?

      I have a Model T Ford buzz coil set up with 6v game camera batteries,
      I’ve used to run RBM outboards, that I could use, if that will work.

      I made a new “air gap” tester that will work on my Bendix twin’s two coil system.
      The Bendix coils primary’s are wired in series, and it’s a twin opposed motor,
      hence both plugs fire at once.

      Thoughts? Thanks.

      Coil-Test

      DSCN8710

      DSCN8716

      DSCN8717

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      #283089
      joecb
      Participant

        US Member

        I would think that by 1938 it would be a standard Ford 6 V coil, not the model T buzz coil.  Looks like what is going on here is using the Ford coil primary voltage spike to juice the Bendix coil. Normaly one would just use low voltage  ( 6 maybe 12 V) to test a coil, but the voltage from the shorted Ford coil will be considerably higher, like a couple hundred volts… ( I think ?)  We need Jeff R to chime in on this.

        Joe B

        #283091
        The Boat House
        Participant



          I’m wondering if not using a 6 volt car battery and
          substituting the needles will produce the same results?
          Looking forward to hearing what you experienced
          with your testing.
          Tubs

          #283092
          Tom
          Participant

            US Member

            While the dates don’t match up, I think they DO mean a Model T Coil.  Using the primary side of a Model T coil would generate the same thing as using a Merc-O-Tronic or a Stevens tester with a vibrator tube.  I’ve done this with a Model T coil and one of the dual output military coils to run opposed twins with no magneto.

            If you put the Bendix primary wires in series with the battery and the top and bottom terminals of a Model T coil, you should be generating a spark in the Bendix secondary.  You would have to put the Bendix high tension wires near each other to see the spark.

            Tom

            #283093
            seakaye12
            Participant

              US Member

              Buc…is that from a Bendix Manual for outboard repair?  Is it available as a PDF somewhere?

              #283097
              joecb
              Participant

                US Member

                I think Tom is correct. The Model T coil has the “vibrating” points – the make and break function on the primary circuit that’s needed to fire the test coil

                Joe B

                #283098
                Buccaneer
                Participant

                  US Member

                  I would think that by 1938 it would be a standard Ford 6 V coil, not the model T buzz coil.  Looks like what is going on here is using the Ford coil primary voltage spike to juice the Bendix coil. Normaly one would just use low voltage  ( 6 maybe 12 V) to test a coil, but the voltage from the shorted Ford coil will be considerably higher, like a couple hundred volts… ( I think ?)  We need Jeff R to chime in on this.

                  Joe B

                  Joe, if one used a regular 6 volt battery, and omitted the
                  extra coil, or Ford buzz box, one would have to operate
                  the points manually to get a spark perhaps????

                  Maybe using the Ford T coil with the vibrating points
                  is why the diagram shows it working with the points
                  isolated??

                  Prepare to be boarded!

                  #283099
                  Buccaneer
                  Participant

                    US Member



                    I’m wondering if not using a 6 volt car battery and
                    substituting the needles will produce the same results?
                    Looking forward to hearing what you experienced
                    with your testing.
                    Tubs

                    Hopefully I don’t report back “Disaster”, as those
                    coils would be few and far between, and not
                    easy to swap out.

                     

                     

                    Prepare to be boarded!

                    #283100
                    Buccaneer
                    Participant

                      US Member

                      While the dates don’t match up, I think they DO mean a Model T Coil.  Using the primary side of a Model T coil would generate the same thing as using a Merc-O-Tronic or a Stevens tester with a vibrator tube.  I’ve done this with a Model T coil and one of the dual output military coils to run opposed twins with no magneto.

                      If you put the Bendix primary wires in series with the battery and the top and bottom terminals of a Model T coil, you should be generating a spark in the Bendix secondary.  You would have to put the Bendix high tension wires near each other to see the spark.

                      Tom

                      Your theory sounds very plausible to me.
                      One would think that it would be safe for the Bendix coils
                      if it’s a procedure in the Bendix shop manual.
                      Thanks.

                      Prepare to be boarded!

                      #283101
                      Buccaneer
                      Participant

                        US Member

                        Buc…is that from a Bendix Manual for outboard repair?  Is it available as a PDF somewhere?

                        Yes, it’s an official Bendix manual for repairmen.
                        I have it in four separate pdf’s, all but one too large of a file
                        to post here.
                        I found it online a few years ago…….. not sure if it’s still “out there”.

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