Figure 6 is a capacitor-less unit built on a LS3 coil, part no. Also, almost any LS2, 3 or 4 engine coil will likely work. When the capacitor is left out, Evac 1 becomes even simpler: three resistors and a coil. Most observable parameters stay about the same, except time to first spark drops to 0.5ms, way faster than a Model T buzz coil.

If you feel your operating conditions are near normal, leave it out. I have found that the capacitor is only needed in very unusual operating conditions, but as there are conditions where it is needed I have included it in the schematic. The above information should give you a very nice buzz coil. (figure 6) Components soldered directly to LS3 coil pins. One key point is that it uses no pesky expensive semiconductors (transistors, integrated circuits, diodes, etc.) that can be put in backwards and blow up.

Together with Evac 1 being so inexpensive and simple, I thought it was time to get it back off the shelf and try to remember the resistor and capacitor values. That inspired me to find out how Jim’s was doing, and it turns out he has been using it for four years without a problem. Recently, however, the complex 555 timer system came up again on an engine website. In fact, never expecting to return to it I threw the schematic away. After building one for Jim and another for myself, I put the project on the shelf. By nasty I mean a much longer arc and a much faster spark rate than the old Model T-type buzz coil. Using just three resistors, a General Motors LS2 engine coil and a capacitor, I created a pretty nasty buzz coil. Starting with one of those coils would have several advantages: built in power transistor, built in trigger mechanism, and small size and light weight. The modern “single coil per cylinder” scheme used in newer cars uses, as the name implies, a separate coil for each cylinder that is activated by a small 5-volt logic signal from the engine computer. After giving the challenge some thought, it seemed there ought to be a much simpler way. The oscillators are usually the universal 555 timers, which require several resistors and capacitors around them, while the standard car coil is big and heavy. A few years back, fellow engine enthusiast and friend Jim White threw me a challenge: Could I make a simple, all-electronic buzz coil? I had seen several schematics over the years, but all of them required two or three power transistors, some form of oscillator and an automotive ignition coil.

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