Re: Dual point distributor in '41 120

Posted by Jim On 2008/4/2 10:46:13

Mal,

An ignition coil is an electro-magnet; an electro-magnet that induces its magnetic field into another set of windings to step up voltage, and reduce amperage. This process is known as mutual induction. An electro-magnet only takes a fraction of a second to energize, reaching full magnetic strength.

Where dual points came in is when performance V-8's began turning high RPM's say 5500 ? 6000 + revs. As RPM's increase, the time (dwell) for the coil to build full field (and best production of spark) is diminishing. As Owen said, the leading set of points breaks, collapsing the magnetic field, inducing the secondary windings transforming voltage amperage values and discharging. The trailing set of points are almost instantly closing to allow the primary coil to begin building the magnetic field, achieving full electro-magnetic saturation.

On a high RPM performance engine such as a V-8, maybe. On a 2600 rpm flat head 8, no. If the coil has time to fully saturate, there is no advantage.

I would investigate the availability of a pertronics electronic conversion (some PI Packard clubs offer as club projects for sale) because points made today are just not what they used to be. The rubbing blocks are not lasting so long, and the contacts don't seem to last so well. NOS sets do pop up on eBay from time to time.

Best of luck,
Jim