59ab no spark

[rbone]

Need help all. No spark on stock 59ab with crab distributor....

Both coil windings show correct resistance. Distributor tests fine on the bench (both points gapped at .015, cleaned, and ground to the housing when closed and are not grounded when open). When I 'bypass' the rotor and cap and go straight from the high tension wire to a plug wire, I get spark. But when I plug the high tension wire into the cap, nothing. I cleaned the rotor and cap terminals, but still nothing.

I don't know what else to do other than to replace the cap and rotor. But they look fine. Before I start throwing parts at it, any ideas?

Thanks,
Ron

[Flathead]

Sounds like a bad rotor, spark leaks through rotor and grounds to dist. shaft. Spin it over without the cap and see if the high tension wire will spark to the rotor, if it does the rotor is bad.

[rbone]

Update - both coils I have test fine measuring resistance through the primary and secondary windings. But I put a coil from one of our old Ford tractors in and all is good again. Running like new now. I guess the old coils were generating just enough to make a weak spark that could travel directly to my spark tester, but not enough to get through the rotor, dist, wires, and plugs. Interesting learning. I must assume the coils are shorting out internally when sufficient voltage/current is applied.

I will send one down to Skip Haney to rebuild and go ahead and replace the rotor while I am at it.

Ron

[Seth Swoboda]

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