I'm reading this tread, and a lot of all treads in Engine Conversion to. I'm buidling an ignition (CDI) based on the gas burner ignition. In original it works from 1xAA cell for a long time. I changed the step up coil from original (it delivered not enough current to charge the capacitor). I wired the coil on a standard ferro (7mm diameter and 40mm long) in a 3 layer (450 windings 0,2mm; 20 windings 0,57mm and 10 windings 0,2mm - just like the jmj). It provides me about 100-120V from a 5V supply. In the spark coil the important thing is the spacers between sections of the secondary. The standard isolation on the wire doesnt provide isolation above 1kV. My ignition does a standard spark without advance.

Sorry aobuot my english but it's my first post on the english language forum (before I only red).