The High-Energy Ignition (HEI) distributor with Electronic Spark Control (ESC) combines all necessary ignition components in one contained unit. The system includes:
All spark timing changes in the HEI (ESC) distributor are performed electronically by the Powertrain Control Module (PCM). The PCM monitors information from various engine sensors, computes the desired spark timing, and signals the distributor to change the timing accordingly. A back up spark advance system is programmed into the ignition module in case of PCM failure. No vacuum or mechanical advance is used.
REMOVAL & INSTALLATION
During the distributor removal and installation, it is very important that the engine crankshaft not be rotated. If rotated, the reference marks made during removal will have to be disregarded. If the engine is accidentally rotated, the timing will be disturbed. If this is the case, make sure to follow the appropriate distributor installation procedure.
- Disconnect the negative battery cable.
- Label and disconnect all wires leading from the distributor cap.
- Remove the four bolts from the distributor cap and move the cap out of the way. Note the position of the distributor cap prior to removal.
- Detach the six terminal connector from the distributor, if not already done.
- Using a distributor wrench, remove the distributor hold-down nut and clamp.
- Matchmark the rotor-to-distributor body and the distributor body-to-engine positions. Pull the distributor upward until the rotor just stops turning counterclockwise and again note the position of the rotor. Remove the distributor from the engine.
Timing Not Disturbed
- To install the distributor, rotate the distributor shaft until the rotor aligns with the second mark, when the shaft stopped moving. Lubricate the drive gear with clean engine oil and install the distributor into the engine. As the distributor is installed, the rotor should rotate to the first alignment mark; this will ensure proper timing. If the marks do not align properly, remove the distributor and reinstall. Be sure to install the thrust washer on the distributor shaft prior to installation.
- Install the hold-down clamp and distributor clamp nut. Tighten the nut until the distributor can just be moved with a little effort.
- Connect the six terminal harness. Install the distributor cap and secure with the four retainer bolts.
- Connect the coil harness and the ignition switch battery feed wire at the distributor cap.
- Connect the negative battery cable.
- Adjust the ignition timing. Once the timing has been adjusted, tighten the distributor hold-down nut to 20 ft. lbs. (25 Nm).
If the engine was accidentally cranked after the distributor was removed, the following procedure can be used for distributor installation.
- Remove the No. 1 spark plug.
- Place your finger over No. 1 spark plug hole and crank the engine slowly until compression is felt.
- Continue cranking slowly until the timing mark on the crankshaft pulley aligns with the 0 degrees on the engine timing indicator. At this point, No. 1 piston is at the TDC of its compression stroke.
- Position the distributor in the block but do not allow it to engage with the drive gear.
- Rotate the distributor shaft until the rotor points between No. 1 and No. 8 spark plug towers on the distributor cap. Install the distributor into the engine. If correctly installed, the rotor will point toward the No. 1 tower in the distributor cap when it is fully installed in the engine.
- Install the hold-down clamp and tighten the nut until it is snug, do not tighten at this time.
- Connect the ignition feed wire.
- Install the distributor cap and spark plug wires.
- Check the engine timing and adjust as required. Once the timing is set to specifications, tighten the distributor hold-down nut to 20 ft. lbs. (25 Nm).
- Installation is the reverse of the removal procedure.