The crank triggered ignition is a complete system for ignition. Since no ignition curve is needed, a simple system is possible. Once you see it you will say to yourself ......."it's so obvious"
Then you need a control for mixture and you are finished.
A thick aluminum disc is drilled through front to back with a drill size a bit smaller than a 3/16" bolt. You press a 3/16" bolt through that hole. Trim off excess bolt front and rear. Place disc in lathe and turn diameter until about 25% of the bolt is exposed. Plan the diameter so as to be just a bit bigger than a "Mr. Gasket" degree wheel. Makes timing a breeze. Provide a spigot or some locating device to keep the disc centered on the front pulley.
Mount two pickups 180 degrees apart along side the disc so that the bolt (reluctor) can excite the pickup. I used the hall effect pickup from a 70s Chrysler, Dodge, Plymouth distributor. MSD makes them as well but they are rather large. Bosch and many others make pick ups to measure wheel speed
for anti skid brakes. You can use any after market amplifier such as MSD or Mallory Hifire. The first one I built used two Chrysler amplifiers from the 70s.
It does not matter where along the disc you mount the pickups. So long as they are 180 degrees apart.
One pickup will trigger a spark(s) for the front housing. The other pick up will trigger a spark(s) for the rear housing.
Both leading and trailing plugs on each housing are fired at the same time. A double ended coil from an early Oldsmobile is what I used. You can use one from a motorcycle with the low powered amplifier.
Or if you use the MSD or Mallory you can use the low resistance racing coils from those manufacturers. The MSD delivers 450 volts to the primary so a stock or motorcycle coil will last a very short time. If counting on one coil per housing does not appeal to you, you can fire one coil for leading and a second coil for trailing when using the MSD or HiFire. Use coils recommended by the amplifier manufacturer. In that case, one coil failure will not stop the engine.
Rotate engine to TDC front housing. Temporally clamp degree wheel to the disc with the TDC mark adjacent to the pointer (you have manufactured). Now rotate the engine backwards until the timing you want to run is adjacent to the pointer. Say 24 degrees. Now with out moving the engine, remove the degree wheel. Rotate the disc (without moving the engine) until the reluctor is adjacent to the pickup for number one housing.
Fasten the disc to the front pulley in some fail safe method, without moving the engine. Attach the degree wheel to the disc with the number on the degree wheel adjacent to the pointer at the 24 degrees BTDC mark. Attach the degree wheel to the disc (without moving the engine) and you are in business. If timing seems to move backwards 5 to 10 degrees as you rev the engine, switch the leads to the pickup. Now it should move back only a degree or so as you rev the engine. Check the timing at cruise RPM. Small timing changes can be made if the mounting method for the pickups has slotted holes. Timing will be rock solid.
Lynn E. Hanover
In a message dated 9/18/2018 10:54:43 AM Eastern Standard Time, flyrotary@lancaironline.net writes: