GM Corvette 1984-1996 Repair Guide

Distributor Cap and Rotor

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REMOVAL & INSTALLATION



The 5.7L (VIN J) engines uses a Direct Ignition system which uses an ignition coil in place of a distributor. The 5.7L (VIN 8) engine uses a conventional High Energy Ignition (HEI) distributor. The 5.7L (VIN P & 5) engines are equipped with a distributor that is mounted on the front of the camshaft.

5.7L (VIN 8) Engines

See Figures 1 through 11

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner cover and/or intake manifold plenum extension, as necessary.
  4.  
  5. Remove the distributor shield.
  6.  



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Fig. Fig. 1: Unfasten the plenum extension Torx® retaining screws



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Fig. Fig. 2: Remove the plenum extension for access to the distributor cap



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Fig. Fig. 3: Remove the distributor shield by pulling it up, off the spark plug wires

  1. Disconnect the ignition switch battery feed wire and tachometer lead (if equipped) from the distributor cap.
  2.  



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Fig. Fig. 4: Unplug the ignition switch battery feed wire and tachometer lead from the cap

  1. Tag and unplug the coil connectors from the cap. Do NOT use a screwdriver, or equivalent tool to release the locking tabs.
  2.  



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Fig. Fig. 5: Tag and unplug the coil connectors from the cap, but do NOT use any type of prytool to release the locking tabs

  1. If necessary for access, tag and disconnect the spark plug wires, then release the spark plug wire harness latches, then remove the wiring harness retainer. The spark plug wire numbers are indicated on the retainer.
  2.  

If you are replacing the cap with a new one, label and disconnect the spark plug wires from the distributor cap

  1. Remove the distributor cap by using a screwdriver to turn the 4 retaining latches counterclockwise, or unfastening the 4 retaining screws, depending upon the vehicle. Move the distributor cap out of the way.
  2.  



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Fig. Fig. 6: On this 1986 vehicle, use a ratchet with a long extension to loosen the distributor cap bolts



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Fig. Fig. 7: Carefully lift the distributor cap up, and remove it from the vehicle

The rotor is secured with 2 screws and has a slot which fits over a square lug on the advance weight base, so that the rotor can be installed in only one position.

  1. Remove the 2 retaining screws, then lift the rotor from the distributor.
  2.  



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Fig. Fig. 8: Unfasten the 2 rotor retaining screws ...



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Fig. Fig. 9: ... then pull the rotor straight up to remove it from the distributor



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Fig. Fig. 10: Exploded view of the HEI distributor cap and rotor, and related components-5.7L (VIN 8) engines

To install:
  1. Place the rotor on the distributor; it can only be installed in one position. Install the 2 rotor retaining screws.
  2.  
  3. Position the distributor cap over the distributor and secure the 4 latches by turning them clockwise with a screwdriver, or installing the 4 retaining screws, as applicable.
  4.  
  5. If removed, attach the spark plug wires, as tagged during removal, then install and secure the wire retainers.
  6.  
  7. Attach the coil connectors to the cap, as tagged during removal. Make sure the locking tabs are fastened securely.
  8.  
  9. Connect the tachometer lead (if equipped) and the ignition switch battery feed wire to the distributor cap.
  10.  
  11. Install the distributor shield.
  12.  
  13. Install the air cleaner cover and/or intake manifold plenum extension, as necessary.
  14.  
  15. Connect the negative battery cable.
  16.  

5.7L (VIN P & 5) Engines

See Figure 11

Removal of the distributor cap and rotor on these vehicles requires the use of two special tools; an ignition distributor cap socket (tool J 39997 or equivalent), and ignition distributor rotor socket (tool J 39998 or equivalent).


WARNING
The distributor and timing disc assembly must be kept clean and free of oil, dirt and engine coolant. Any contamination may cause engine misfire and/or distributor damage. Do not disassemble the distributor until all debris has been cleaned from the distributor and surrounding area.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the water pump and crankshaft balancer assembly, as outlined in Engine & Engine Overhaul of this repair guide.
  4.  
  5. Tag and disconnect the spark plug wires from the distributor assembly.
  6.  
  7. Unplug the 4-terminal PCM connector and vacuum harness from the distributor. Plug or cap the vacuum line to prevent any debris from entering.
  8.  
  9. Use a suitable distributor cap socket, tool J 39997 or equivalent, to remove the distributor cap bolts/screws. Remove the distributor cap.
  10.  
  11. Use a suitable distributor rotor socket, tool J 39998 or equivalent bit, to unfasten the retaining bolts/screws, then remove the rotor.
  12.  
  13. If necessary, remove the distributor cover and shield at this time.
  14.  


WARNING
Do NOT touch the timing disk sensor or distributor base.

  1. Inspect the distributor base and timing disk for damage, corrosion, or plastic particles. If you find any, the entire distributor assembly must be replaced.
  2.  
  3. The distributor is driven by a camshaft pin that mates to one slot in the distributor driveshaft. Align the distributor driveshaft with the distributor base timing mark.
  4.  
  5. Rotate the engine crankshaft until number one piston is at Top Dead Center (TDC) with the intake and exhaust valves closed. The camshaft pin will be in the 9 o'clock position.
  6.  



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Fig. Fig. 11: Exploded view of the distributor cap, cover, rotor and base assembly-5.7L (VIN P & 5) engines

To install:
  1. If removed, install the distributor shield and cover.
  2.  
  3. Position the rotor, then secure with the retaining screws/bolts. Tighten the screws to 6 inch lbs. (0.7 Nm).
  4.  
  5. Place the distributor cap on the distributor assembly and install the retaining bolts/screws. Tighten the cap bolts/screws to 25 inch lbs. (2.8 Nm).
  6.  
  7. Unplug and connect the vacuum harness to the distributor.
  8.  
  9. Attach the 4-terminal PCM connector to the distributor. Connect the spark plugs to the distributor, as tagged during removal.
  10.  
  11. Install the crankshaft balancer and water pump, as outlined in Engine & Engine Overhaul of this repair guide.
  12.  
  13. Connect the negative battery cable.
  14.  

 
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