I incorrectly believed that most on this list were familiar with the set-up that I have that uses the MSD 8210 coil selector (yes, it has diode packs inside). Mallory used to make the same thing but I don't find them for sale any longer. My set-up uses two independent triggers for two separate ignition coils. William Wynn recommends a DPDT switch but my set up uses a SPST for each ignition system. MSD instructs that both ignitions NOT be run at the same time while the ones from Mallory said that doing so was OK. Some pilots run both ignitions for take-off & landing and I've heard no bad reports from doing so.Aha! Thanks. So, the complexity is there, just hidden under the plastic.
Dale, any feedback on the in-service reliability of the coil selector in Corvair service? And, if known, what's the typical failure mode (i.e "I can't change to my backup system", or "When the coil selector died, my backup system got fried" etc)
Mark ... I've never had any issue with my ignition set up. None. I've never heard of one of these units failing (though I'm certain it has happened as all things fail eventually). The primary ignition trigger is an electronic unit and the secondary ignition trigger is points. The secondary is timed slightly behind the primary (~ 2º) and both are advanced with the re-curved mechanical advance in the distributor. Total advance is currently 28º BTDC.
One of the VW conversions uses the Dyna S triggers for the coils of the secondary ignition:
The same sort of set up could be used with dual coils through a coil selector. Lots of ways to go at this ...