Dual point distributor question
I can't believe this "alternating fire" crap -- WTH is the advantage compared to a single-point?? .
Google up Mallory "double life" or "rev pol", and "du coil."
There were several issues that older systems tried to solve.
The idea of the 4 lobe (V-eight "double life" was just what the name implied--- Each set of points fires alternating cylinders, so each set only switches have as much as a single point V8. The same, however, is also true of 8 lobe dual point setups --one set closes the circuit, the other points opens the circuit, so each does "half" the work
This is only a guess, but I believe the origin of the "double life" was quite simply that many guys rejected the rev-pol and Mallory simply marketed the 4 lobe as the "double life." I REALLY have never sat down and studied the rev pol, and at my age, have no desire to.
The other problem was getting enough current and dwell time to get performance out of a coil. "Building" the magnetic field in a coil depends on LOTS of variables, but the biggest ones are----------
More current would help spark, but is hell on points, hence dual points of some sort
More current helps the coil build spark, so ANY system is better than single points
Dwell TIME is the amount of distributor rotation in degrees (or time) that the points are CLOSED. You cannot simply set V8 single points for more dwell, because this closes them up more, and they start arcing worse and worse as you close them up. There is a practical limit, which is why traditional V8 single points were 'averaged' at 28-32 degrees---a compromise between points life, wear, and dwell time, and probably other factors such as bounce.
The rev-pol and Du-coil systems took a different approach. In the case of the du-coil, a special distributor, cap and rotor, used 2 points, 2 condensers, and 2 coils. The cap and rotor was essentially firing 2-- 4 cylinder engines (V-eights hooked together. These were a real PITA and just as much trouble to set up. I've only messed with them about 4 times back in the 70's and have been perfectly happy to not ever see one again.
Because each coil only fired half as often, this gave you more time for "dwell" to build up the magnetic field in the coil.
You must remember that this is BEFORE any real decent electronic systems came out, and there were only a few truly HP coils -- the old old black rectangular Mallory, and the then -new great big finned Accel coil.
Du-coil from over at HAMB. Essentially 2 -- 4 cylinder ignitions in one distributor housing
http://www.jalopyjournal.com/forum/showthread.php?t=443192&highlight=titus