Coil hookup question

Jon B
Jon B Administrator
edited November -1 in HUDSON
I need some advice!



I just obtained a very nice NOS coil for my '37 Terraplane (thank you, Lance Walker!) but there's a dilemma:



The original coil had a terminal at the bottom (next to the hi tension socket) for the wire going to the side of the distributor. At the top was one terminal for the ignition switch wire (mine is the old style with an armored cable running to the ignition switch, which houses that wire).



BUT, the new coil has TWO such terminals at the top, each one sticking out the side of the coil. Neither one marked, as to what it goes to.



Has anyone dealt with this sort of thing before? Is there a way to test either terminal (say, with a continuity tester) to determine which will be the correct terminal to attach the ignition switch wire to? I'm not the most knowledgeable, when it comes to ignition systems.

Comments

  • Unknown
    Unknown
    Jon,



    If I remember correctly, an old method was to remove a spark plug wire and hold a lead pencil between it and the spark plug while you crank the engine. If you get spark between the pencil and plug, then the polartity is correct. If you get spark between the wire and pencil, then the polarity is reversed. Obviously, this is done with the coil connected. Even if the wiring is reversed, nothing bad will happen. And, like I mentioned recently, reversed polarity at a coil is easily detected as your engine will stumble at high speeds.



    Hope that helps.
  • [Deleted User]
    [Deleted User]
    Seems like I saw the pencil trick in a old Motor Repair Manual. Havent used it lately. But it works. I used it on a Model A. Good luck, Bob
  • [Deleted User]
    [Deleted User]
    Jon:

    I looked in my oldest Motor's Auto Repair Manual 1951, page 12 it discusses using a voltmeter to determine polarity. Maybe you can find it in an old manual. Good luck, Bob
  • Jon B
    Jon B Administrator
    Here's the top of the coil. A cover (with an armored cable) on the car, fits over this and is held down with the little tabs you see. The wire to the ignition switch (within the armored cable) is supposed to attach to the terminal at the top of the coil.



    In this case, we have TWO terminals to choose from (the little "spikes" that penetrate the sides of the coil housing). Neither is marked. Mystery!



    (There is a second terminal at the bottom of the coil, and the wire from the side of the distributor connects to this. Then, of course, we have the high tension wire to the distributor cap, also at the bottom).



    So.... the question is....which of those two terminals do I attach the ignition switch wire to? (He asked, sweatily, as his trembling hand moved the wire ever closer to one of the the two mystery terminals....)
  • mars55
    mars55 Senior Contributor
    Jon B wrote:
    Here's the top of the coil. A cover (with an armored cable) on the car, fits over this and is held down with the little tabs you see. The wire to the ignition switch (within the armored cable) is supposed to attach to the terminal at the top of the coil.



    In this case, we have TWO terminals to choose from (the little "spikes" that penetrate the sides of the coil housing). Neither is marked. Mystery!



    (There is a second terminal at the bottom of the coil, and the wire from the side of the distributor connects to this. Then, of course, we have the high tension wire to the distributor cap, also at the bottom).



    So.... the question is....which of those two terminals do I attach the ignition switch wire to? (He asked, sweatily, as his trembling hand moved the wire ever closer to one of the the two mystery terminals....)



    My feeling is that ignition switch wire is NOT connected to the two terminals (the little "spikes" that penetrate the sides of the coil housing). It is connected to the third terminal at the top of coil in the picture. Why, well the purpose of the armored cable is to prevent the car from being "Hot Wired" and if the ignition switch wire connection is exposed the car can be stolen by connecting a wire from the battery to the exposed terminal which defeats the purpose of the armored cable .
This discussion has been closed.

Categories

In this Discussion