egnition (is that spelled right)?

[geraldchainsaw]

short story,    changed my electronic egn to points again,   for some reason it didn't work,    checked everything,  ,last thing i took apart was to pull the wire from the ballast rresistor,  instead it fell off in my hands,  and thats why it  didn't work,   but now my question,   so i put back on the electronic egn and it started right up,  now,   will someone explain to me why i lost the  dwell reading??       jerry

[JimNolan]

Jerry,
   Here goes. The reading you are looking at is the amount of degrees that a set of points ( mechanical or electronic ) are closed during the rotation of the distributor cam. The importance of this is that it takes time for the coil to collapse when the points are closed. When the coil collapses that is what supplys the high voltage going to the spark plugs. If you make that time too long or too short the coil will not function correctly. Thus, you may have a coil that does'nt completely collapse or doesn't fully charge and there could be less voltage going to the spark plugs. The amount of degrees that the points are closed (8 lobes) added to the amount of degrees of the flat spots on the cam will equal 360 degrees. Your meter tells you only the amount of time your points are closed.
   Now, I'm going to tell you why your electronic ignition module and your coil has to be matched. The two terminals on your coil are connected to the primary windings of your coil. These windings have a resistance. And, if you have a ballast resistor you're adding more resistance through that circuit. The positive terminal of the coil has positive voltage applied. The negitive terminal goes to whatever device (points or electronic module) that make a ground circuit. Thus when you make ground with the points current flows through the primary windings. Thats great, and it works every time for a set of points. But, if you've got an electronic moduale you're using solid state devices ( transistors, etc ) to make the module work. These solid state devices work only on current. Don't get me wrong, voltage has an effect on current but it's current that does the work. When you have a set voltage and change resistance in a circuit the current will change in that circuit. These modules will tell you how much resistance they want going through the circuit for their module to work correctly. They don't tell you to get a 3 ohm, 4 ohm, 6 ohm etc. coil just to sell you a new coil. They tell you this to make sure their module will work correctly. If you have too little current flowing through the module you can damage it or impede it's designed characteristics. The dwell meter reads the amount of time that the negitive terminal on the coil is grounded. If it does'nt show a reading you may be collapsing the coil long enough to run the engine but not completely collapse the coil. Jim PS I'm sorry that this is so involved.