BMW Coupes and Sedans 1970-1988 Repair Guide

Distributor

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REMOVAL & INSTALLATION



Timing Undisturbed
1970-83 4-CYLINDER ENGINES

See Figures 1 and 2

These distributors are vertically mounted at the rear of the engine.

  1. Prior to removal, use paint or chalk to scribe alignment marks showing the relative position of the distributor body to its mount on the cylinder head. Put marks on both the cylinder head and distributor body.
  2.  
  3. Mark each spark plug wire at the spark plug, with a dab of paint or chalk noting its respective cylinder position. Remove the plug wire from the spark plug. Continue this until all the spark plug wire are removed.
  4.  

It will be easier to install the distributor cap if you leave the plug wires attached in the cap.

  1. Disconnect the high tension cable leading front the coil to the center of the distributor cap.
  2.  
  3. If equipped, remove the spark plug loom retaining nut(s) from the cylinder head cover.
  4.  
  5. Tag then disconnect the vacuum line(s) from the vacuum capsule on the distributor.
  6.  
  7. Unsnap the distributor cap retaining clasps and lift off the cap and wire assembly.
  8.  
  9. With the aid of a remote starter switch or a friend, "bump" the starter a few times until the No. 1 piston is at Top Dead Center (TDC) of its compression stroke, If aligned correctly, the notch scribed on the metal tip of the distributor rotor will be aligned with a corresponding notch scribed on the distributor case. Before removing the distributor, make sure that these 2 marks are in correct alignment.
  10.  
  11. Loosen the clamp bolt at the base of the distributor and lift the distributor up and out. You will notice that the rotor turns clockwise as the distributor is removed.
  12.  



Click image to see an enlarged view

Fig. Fig. 1: Before removing the distributor, align the marks on the rotor with the marks on the distributor body



Click image to see an enlarged view

Fig. Fig. 2: Before installing the distributor into the hole, turn the rotor 1.4 inches (35mm) counterclockwise to properly align the gears during installation

To install:
  1. Slide the distributor into position, rotating the rotor approximately 1.4 inches (35mm) counterclockwise from the notch scribed in the distributor body. This will ensure that when the distributor is fully seated in its mount, the rotor and distributor marks will coincide. When the scribe marks on the parts align as well as the painted/chalked marks also align, tighten the hold-down bolt by hand so the distributor will not move while installing the remaining parts.
  2.  
  3. Position the distributor cap and spark plug wires on the distributor body and secure the clips. If the clip will not engage, it most likely means the tab on the cap is not aligned correctly with the tab in the distributor. Remove and try again.
  4.  
  5. Connect each spark plug to its respective spark plug. If equipped with a loom or bracket for the spark plug wires on the cylinder head cover, secure using the retainer nuts removed earlier.
  6.  
  7. Connect the vacuum line(s) to the distributor.
  8.  
  9. Connect the high tension wire and battery negative cable.
  10.  
  11. Adjust the ignition timing as described in Engine Performance and Tune-Up . Tighten the hold-down bolt to 8 ft. lbs. (10 Nm).
  12.  

1970-83 6-CYLINDER ENGINES



See Figures 3 and 4

  1. Disconnect the negative battery cable.
  2.  
  3. Tag and remove the vacuum hoses for advance and retard from the distributor.
  4.  
  5. With chalk or paint, mark the relationship between the distributor body and the cylinder head. Paint/chalk marks on both the cylinder head and distributor body.
  6.  
  7. With the aid of a remote starter switch or a friend, "bump" the starter a few times until the No. 1 piston is at Top Dead Center (TDC) of its compression stroke, If aligned correctly, the notch scribed on the metal tip of the distributor rotor will be aligned with a corresponding notch scribed on the distributor case. Before removing the distributor, make sure that these 2 marks are correctly aligned. Also make sure that the TDC timing marks on the flywheel or balancer pulley are in line.
  8.  
  9. Loose the clamp bolt at the bottom of the distributor.
  10.  
  11. Unscrew the mounting bracket screw for the electrical connector on the distributor body, pull the mounting bracket off, and unplug the connector.
  12.  
  13. Pull the distributor out of the cylinder head.
  14.  



Click image to see an enlarged view

Fig. Fig. 3: Align the scribe marks on the rotor and distributor body, as well as the flywheel



Click image to see an enlarged view

Fig. Fig. 4: Before installing the distributor, turn the rotor 1.0-1.5 inches (25-38mm) counterclockwise to properly align the gears

To install:
  1. Position the rotor 1.0-1.4 inches (25-38mm) counterclockwise from the notch in the distributor housing.
  2.  
  3. Position the distributor body into the cylinder head so the alignment marks you made in Step 1 are aligned.
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  5. When the distributor is fully seated, reconnect the electrical harness, vacuum lines and install the cap.
  6.  
  7. Connect the negative battery cable.
  8.  
  9. Adjust the ignition timing as described in Engine Performance and Tune-Up .
  10.  

1984-88 MODELS

Engines produced in model year 1984 and later are equipped with the Digital Motor Electronics (DME) control system. The distributor on these models is contained within the engine itself. Other than distributor cap and rotor removal and installation, no general service is possible.

Timing Disturbed

If the engine is accidentally turned while the distributor is removed, it will be necessary to find the TDC position for No. 1 cylinder before installing the distributor.

  1. Remove the cylinder head cover by unfastening the retaining nuts. Depending on the model, certain brackets and hoses will also have to be removed.
  2.  
  3. With the cylinder head cover removed, and the valves clearly visible, rotate the engine crank by either placing the vehicle in gear (manual transmission equipped models only), and rocking the vehicle back and forth, or rotating the crack with a socket and breaker bar attached to the nut on the crank pulley. Rotate the engine in the direction of normal rotation until the last cylinder's valves are open the same amount. For a 4-cylinder model, watch cylinder No. 4 valves, for a 6-cylinder model, watch cylinder No. 6.
  4.  
  5. When both valves are open the same amount, proceed to install the distributor.
  6.  

 
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