I have almost gone the full circle.
Something I have been playing with. 2 commercial trigger systems mounted on the centrifical advance plate in a standard VW distributor. If I set the springs up to give me the advance curve I want (Using my home made distrubtor analizer) I can have a nice retarded spark for starting and 30 + degrees advance at max RPM and of course everything in between. With the 2 triggers I can have dual ignition with 2 dual output coils. There is one thing I don,t like, the dwell angle/time is much too long , consuming way too much power.
The little magnets only turn off the power to the coil for 12º which means it is turned on for 168º before the next spark and at 3000 RPM engine or 1500 rpm distributor 168º takes 18.6ms about 15ms more than needed and thats at maximum revs , at lower revs it,s much longer. Apart from wasting lots of power the coil would run very hot.
The very first ignition system I bult solves this problem by only turning the coil on a few milli seconds before the spark is needed but it was not reliable so I went away from it.
The magnetic triggers The cam drive , I had to machine half of the cam off because it was hitting the triggers. The top half is enough to drive the disk with the magnets. There are 4 magnets, I will have to remove 2 for a 2 cylinder engine. The cover and the distrubitor testing system under construction. Yet another ignition system.
My solution to the dwell angle/time problem is use CDI instead of an inductive system because with CDI the long dwell is not an issue, once the capacitor has recharged ready for the next spark the system draws minimal power.
A beautiful advantage of the CDI system is it has a multi spark feature. While of no value when the engine is running it is of great value when hand starting a cold engine.
Imagine inside the cylinder during starting , 2 spark plugs with 10 sparks in 5-6ms each time you flick it over.
Check out the Rolls Royce Merlin shower of sparks ignition system they used to get a 27 litre 12 cylinder engine started during WWII, without using modern electronics.
The last photo is the first system I was going to use because it is smaller and more compact with surface mount IC,s but I had problems with it so it went in the bin in favour of an older design with all through hole components.
