Mallory Dist Comp SS to Mallory HyFire VI

Variable reluctance ignition triggers on a positive pulse preceded by a negative pulse. Observing at reluctor and pickup position, reluctor tooth approaches pickup nub, and signal goes negative, when aligned to nub signal is at zero, just as tooth is passing trailing edge signal goes positive, trigger happens, spark triggers light.

If polarity is incorrect, trigger occurs as reluctor tooth approaches pickup leading edge. While that error is more than a tooth width, triggering in that manner, is not consistent. Negative pulse happened on prior tooth, then reluctor passes in long distance between teeth, positive pulse happens at a slow ramp on leading edge of next tooth, that may deviate with noise, or have false triggers.

Timing light will show reluctor and nub position, and also tower phasing.