cast iron Prestolite/Pertronix ignitor conversion

KitCarlson said
There best approach is to use an independent pickup circuit as suggested in post 7. The coil is replaced by a power resistor of a few to several Ohms, Pertronix wired in normal fashion. Black wire that goes to power resistor is trigger point, attenuate with 3 to 1 resistive divider with 5V clamp circuit. I can help with that stuff. Conditioning a coil primary signal is possible, but much more invloved to shave the ~400V peak and oscillations that follow.

Not sure I follow about taking selected, 4th, 6th, or 8th. If that is what is available, it won't work, need all triggers. Not sure how the Sun does individual cylinder timing checks.

Does anyone know if the Sun has a reference pulse per revolution?

The Sun uses an amplifier (see it on the left side of photo) for magnetic pickup distributors. I'm not sure where the signal then goes. But it seems it must pickup every pulse whether points or amplified. On the lower right of the machine there is a selector switch for the number of cylinders. However that might just be for the tach. I do know the tach signal relates to a points type unit working off the machine's drive, not from the distributor. That's about the extent of my knowledge on the workings. Halifaxhops knows a lot more about them than I.