1975 AND LATER MODELS
See Figures 1, 2 and 3
There are two major differences from the point type systems: First, the points and condenser are replaced by an induction type impulse sender. Second, an electronic module has been added to amplify the electrical impulses between the distributor and coil. The impulse sender is located inside the distributor where the points used to be. Instead of opening and closing an electrical circuit, the sender opens and closes a magnetic circuit. This induces impulses in a magnetic pick-up. The sender consists of a stator, pick-up, rotor, and permanent magnet. The stator and armature each have the same number of teeth as there are cylinders. The permanent magnet creates a magnetic field which goes through the stator. The circuit is closed when the teeth are opposite each other. This means that the rotor opens and closes the magnetic field while rotating. This generates current pulses in the magnetic pick-up.
The electronic module is a solid state design which is fully transistorized. It amplifies the impulses from the sender and controls the dwell angle.
REPLACING THE IMPULSE SENDER
See Figures 4, 5 and 6
- Unsnap the lock clasps.
- Remove the cap, rotor and dust cover.
- Remove the vacuum advance unit and the cap hold-down clips.
- Remove the screw securing the contact and pull the contact straight out.
- Remove the impulse sender plate screws.
- Remove the snap ring and shims and pull the rotor straight off along with the small lock pin.
- Remove the snap ring holding the sender and lift off the sender and plate.
- Install the new sender, making sure that the snap ring is properly seated.
- Continue reassembling in reverse order, noting that the screws for the vacuum unit and the hold-down clips are different lengths. When attaching the new sender to the plate, the connector pins should be directly opposite and above the attachment ear on the plate. When installation is complete, rotate the shaft several times to make sure there is no noise or binding.