GM Corvette 1963-1982 Repair Guide

Component Replacement

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See Figures 1, 2, 3 and 4

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Fig. Fig. 1: If it is necessary to remove the spark plug wires, ALWAYS tag them to avoid confusion



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Fig. Fig. 2: Push downward and turn to release the distributor cap hold-down clamps



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Fig. Fig. 3: Carefully lift the cap off the distributor



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Fig. Fig. 4: If not already done, detach the electrical connectors

HEI SYSTEMS - Distributor Cap



  1. Disconnect the feed, module, and tachometer wiring from the drivers side of the distributor cap. Do so by releasing the wiring connector retaining tabs and carefully pulling downward on the connectors.
  2.  
  3. Locate the locking tabs of the spark plug wire retaining ring (on the distributor cap). Move each of the two locking tabs outward to release the retaining ring. With the plug wires still attached to the ring, pull the ring and wires off of the distributor cap and move the assembly out of the way.
  4.  
  5. Release the distributor cap hold-down screws (push downward and counterclockwise) and lift the cap assembly off of the distributor.
  6.  
  7. Remove the coil cover from the distributor cap (4 fasteners).
  8.  
  9. Push the spade terminals upward and out of the distributor cap.
  10.  
  11. Remove the four coil screws and lift the coil, spring, carbon contact, and rubber washer out of the distributor cap.
  12.  
  13. Reverse the previous steps to assemble, using a new cap. Lubricate the rubber washer with dielectric lubricant during assembly.
  14.  

Ignition Coil See Figures 5, 6, 7 and 8

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Fig. Fig. 5: HEI coil-in-cap terminal identification



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Fig. Fig. 6: After removing the coil, check the condition of the arc seal-1981 vehicle shown, others are similar



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Fig. Fig. 7: Loosen the screws securing the rotor ...



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Fig. Fig. 8: ... then carefully remove the rotor from the distributor

Perform steps 1, 2, 4, 5, and 6 of the previous distributor cap replacement procedure. Install the new coil, being sure to use the dielectric compound supplied with most coils to lubricate the rubber washer.

Ignition Rotor

Remove the distributor cap as previously outlined. Loosen the rotor retaining screws (most screws will stay attached to the rotor) and lift the rotor off of the mainshaft assembly. During installation, note the locations of the different locating "dowels" (2) on the underside of the rotor. These dowels help to prevent incorrect rotor installation by allowing the rotor to be installed in only one way.

Vacuum Advance Unit (if so equipped)

  1. Remove the distributor cap and rotor as previously outlined.
  2.  
  3. Disconnect the hose from the vacuum advance unit.
  4.  
  5. Remove the two vacuum advance unit retaining screws and pull the unit outward.
  6.  
  7. Rotate the unit to disengage the operating rod from the distributor.
  8.  
  9. Reverse the previous steps to install.
  10.  

Module See Figures 9 and 10

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Fig. Fig. 9: Make sure the electrical connectors are in good condition



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Fig. Fig. 10: Apply a suitable silicone dielectric compound before installing the ignition module

See Figures 11 and 12

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Fig. Fig. 11: Distributor Specifications



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Fig. Fig. 12: Distributor Specifications

  1. Remove the distributor cap and rotor as previously outlined.
  2.  
  3. Carefully disconnect the wiring from the module.
  4.  
  5. Remove the two module retaining screws and lift the module out of the distributor housing.
  6.  

To install:
  1. Apply a light coating of silicone dielectric compound to the distributor housing in the module mounting area before installing the new module. The silicone compound is used to transfer heat from the module to the distributor housing. If the compound is not used, the module will overheat, causing failure of the ignition system.
  2.  

Silicone compounds are available strictly for this purpose-DO NOT use a regular silicone lubricant or sealer.

  1. Install the new module, using the accompanying illustration as a guide to establish the best possible module connections.
  2.  

Many H.E.I. failures have been attributed to poor module connections. Inspect the wires, terminals, and connectors for damage and follow the accompanying illustration.

  1. Install the rotor and distributor cap as previously outlined.
  2.  

Items previously listed are the only items of the H.E.I. distributor which are serviceable with the distributor installed. Other services will require distributor removal and disassembly.

 
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