<< Hi everyone, I have a 12A carburetted motor that I have converted the
 > leadings to direct fire a la 2nd generation coil/igniter assembly, however
I
 > would like to also convert the trailings. Problem is of course that while I
 > can fire the leadings waste spark, I can't do that with the trailings. The
 > 2nd gen trailing coil used an on/off input to indicate whether rotor 1 or
2,
 > that was generated by the ECU.
 >
 > I am wondering, is there any (relatively) easy way to make a circuit to do
 > the same from the dizzy output? IE, flip-flop triggered by a low voltage
run
 > across the cap & rotor? This seems like it should work but I'm not sure
what
 > kind of signal level I'd get from that.
 >
 > For the leadings, I went into the dizzy and added some new wire and a
 > connector to where the leading igniter plug used to be. Ran those to the
2nd
 > gen igniter input, works good long time. For the trailings though I can't
 > think of a way to easily differentiate between 1 and 2 just looking at the
 > hall-effect sensor.
 >
 > I do have a spare dizzy that I can alter to try suggestions and would be
 > glad to try anything.
 >
 > Thanks!
 >
 > Mike Harrington

 I think it could be done two ways. I know this one works because I did it. I
built an aluminum disc 3/4" thick and the same diameter as a Crane Degree
wheel. I drilled a hole through the edge of the wheel front to back. I
pressed a ten penny nail through the hole and trimmed it off flush with the
surface. I turned the diameter of the wheel down until about one third of the
nail was showing on the edge of the disc. I bolted the disc onto the front
pulley from an early 12A ( 2 v grooves and 4 bolt holes in the front rim). I
mounted Dodge (Plymouth) distributor pickup coils ($4.50) 180 degrees apart
on the front case. I used two Dodge amplifiers, ($16.00) one for each pickup,
to drive a double ended coil, I think it was Oldsmobile, cheap but I don't
remember how much. Both wires from one coil to both plugs on the front
housing and both wires from the other coil for both plugs on the rear
housing. The pickup mountings have to allow for some movement to adjust
timing. Set it +20 or wherever and forget it. It never changes. You can
shriek the engine and the timing light picture looks like the engine is
sitting still. The fast moving reluctor (nail) will produce a whopping pulse
to the amplifier and you must run the wires from the pickups through Dash 4
braided hose and ground the braid. Otherwise you will get major crossfiring
and a dead engine.

The other way is to modify the pickups (or wiring) in the stock system to do
the same thing. Just fire both plugs on each housing at the same time with a
double ended coil, two full size coils or Corvette coils on each plug. You
have to trigger some sort of amplifier to drive the coils and I would use two
MSDs.

On the race car we use an electronic distributor and use just one pickup to
fire both coils through two MSDs. There is little power lost at high RPMs by
not spreading the timing between leading and trailing and some is gained on
the first system with the improved timing accuracy.

Lynn E. Hanover

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