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304065 304065 is offline
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The big problem with hall-effect or optical ignitions like the Allison/Crane or the Pertronix is this: when they fail, you can't diagnose the problem at the side of the road. (Unless you carry a handheld oscilloscope in the car!)

Whereas with points, it's pretty easy to get out a flashlight and the toolkit screwdriver and reset the gap or change the points set entirely, in the dark, in freezing rain, at the side of a highway with semi tractors blowing by at 80 mph, 300 miles from New York City. . . not that I've done that or anything. . .

Anyway. . . how to tell the "Health" of various systems:

1) CDI Box-- do you hear a "whine" when the unit is powered up? That's the oscillator inside generating an AC which steps up +12V to +460V to charge the cap-- it makes the coil windings vibrate hence the whine. . . are all the connections clean? That's decent roadside troubleshooting.

2) Plug wires-- check with ohm meter for continuity and resistance.

3) Points-- check gap, dwell (dwell's not that important with CDI)-- the points current is only 420mA so points wear is negligible over tens of thousands of miles

4) Rotor, cap visual inspection, check resistance

5) Distributor- check advance with dial back timing light, create map of advance curve and compare to factory specs . . . over time. Manually rotate rotor to verify that centrifugal advance working/not seized

6) every connection in the electrical system must be checked to be free of corrosion-- including the grounds.
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Old 07-20-2009, 01:24 PM
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