Model T Buzz Coils

| November/December 2003

  • Ford Model T buzz coil
    Schematic for the Ford Model T buzz coil.
  • SmokStak

  • Ford Model T buzz coil
  • SmokStak

The following comes from a recent topic on SmokStak, which can be found on the Internet at: smokstak.cgi. As ever, various individuals started, commented on and concluded the following bulletin board thread.

Could someone tell me how to check a Ford Model T coil before I go through all the trouble of soldering some clips on the post? - Benny

I hook a 6- or 9-volt battery to the positive and negative terminals of the coil and see if I can make it buzz. Nothing fancy, but it works for me. -Mike

I use an ohmmeter and measure the resistance between the contacts positive, negative and spark terminals. Top (positive) to bottom (negative) should almost be a short, and top (positive) or bottom (negative) to the center (spark) should read a higher resistance. If you get an open circuit then you need to work on it. Usually just cleaning the points and all the connections on the top of the coil does it. Then you may need to adjust the tension on the bottom set of points by bending them at the coil connections just a bit up or down to get the proper BUZZZZZ.

You really need a meter to measure the current draw, which should be around 1.5 amps. More than that has a tendency to burn the points and shorten battery life. Operating the coil without a spark plug or tester connected can cause the secondary to short out and then it's junk. - Paul S.

The top and bottom post are the primary positive and negative. It doesn't make any difference which one you choose. The center button is secondary, but be sure you have a wire with a 1/4- to 3/8-inch gap for the spark to jump. Letting it buzz without a place for the secondary spark to go is asking for trouble because it will find a path inside the coil and burn the insulation. Twelve volts won't hurt it, just don't leave it buzzing. - J.B.


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