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Title: Help wanted: Petronix owner with a dwell meter Post by: Harv on November 11, 2014, 12:20:06 PM Ladies and gents,
For my magneto thread (http://www.fbekholden.com/forum/viewtopic.php?f=25&t=20727), I want to do a brief write-up about the Pertronix Ignitor I (often just called a Petronix). I will do a comparison between maggies, dual-point dizzies and Petronix equiped greys. I have a pretty fair idea of how the Pertonix Ignitor I works, and know that dwell is waaaay different to a standard grey (Pertonix get extra zap in other ways than increasing dwell). Measurements made by some enthusiasts (but not on the grey motor Pertronix 1864a) show dwell is around 27-28º - substantively lower than the factory grey motor 35º to 41º. I'd like to publish the specific number for the grey - does anyone on the forum have a Pertonix installed who can run a dwell meter over it for me please? Cheers, Harv (deputy apprentice sparkplug tester) Title: Re: Help wanted: Petronix owner with a dwell meter Post by: ardiesse on November 24, 2014, 04:42:44 PM Harv,
It took me a while, but I put a dwell meter on my FC, which has a Pertronix ignition module: 28 degrees dwell. I wondered whether the Pertronix units increased the dwell at higher rpm as a way of increasing the spark energy, but no. There was no apparent change in dwell angle with increasing engine speed. Rob Title: Re: Help wanted: Petronix owner with a dwell meter Post by: Harv on November 24, 2014, 06:43:25 PM Thank Rob - very much appreciated. The PerTronix Ignitor I (grey motor) has fixed dwell - the later model Ignitors have variable dwell.
Can I be a pain please and ask another favour? Can you please measure the gap between the magnet ring and the sensor with a feeler gauge? More gap = more dwell. I have one grey motor data point (33.6º with an air gap of 0.040”) and am guessing that your gap is a little tighter than this. Cheers, and thanks, Harv |