The Bergstresser spark firing time delay coil , 1976 Patent 3939814, .8 ohm, 178uh inductance, can be built from the instructions in U.S. Patent on section of pvc pipe and 2 end caps with magnet wire, electrical tape and plastic tie wraps. My unit was built, but not tested awhile back in time. Many US Patents can be downloaded from Internet by number for study. Engines running on fast firing Hydrogen gas require late degrees timing ATDC.