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Re: Re: Re: Ford 9N - coil replacement - simple procedure?
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Posted by RKS on April 26, 1999 at 17:04:45:
In Reply to: Re: Re: Ford 9N - coil replacement - simple procedure? posted by me on April 26, 1999 at 15:29:40:
you're right about the inductance, but the points make contact in the bottoms of the distributor shaft "between" the lobes, and that contact completes the ground from the coil to the distributor. On the compression stroke, the piston rises and the points ride "up" the shaft toward the top of the lobe. As they rise they separate, finally to a distance in which the circuit is finally broken. Here the coil fires, and the points ride "down" the lobe, make contact again, and charge the primary circuit and condenser again. There is no need for a ground via the plug when the points are in contact. It is when the points open that the ground is lost, and at that moment the inductance occurs and the coil "fires" through the distributor-coil wire, through the rotor, cap, and to the plug. And, you are right that the capacitor (condenser) stores the charge, but it stores it during the time the points are closed, and discharges through the primary and secondary of the coil at the instant the points open. In fact, the condenser could be mounted anywhere that it has contact with the neg side of the coil, as long as that position was maintained when the points "open." It is just mounted under the dist cap for convenience and insulation. If you'll think through all this, you'll see this has to be. I used to think the spark happened when the points close enough to "contact." It is just the reverse, however. RKS
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