Volkswagen Air Cooled 1949-1969 Repair Guide

Distributor

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GENERAL INFORMATION





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Fig. Fig. 1 Exploded view of the Bosch distributor utilized on many Volkswagen engines

The Volkswagen is equipped with a 6 or 12-volt battery-operated ignition system. The major parts of the system are the battery, coil, distributor, spark plugs and wiring. The job of the ignition system is to convert the 6 or 12 volts of the battery into voltage large enough to force a spark to jump across the 0.025-0.028 in. (0.6-0.7mm) gap of the spark plug.

The ignition coil has two circuits-a primary circuit and a secondary circuit. The primary circuit consists of heavy wire wrapped around the iron core of the coil, while the secondary circuit is made up of similar windings of fine wire. The separating of the contact points causes the current through the primary winding to cease, which in turn causes the magnetic field to collapse and induce a high-voltage surge to flow through the rotor to a spark plug. The condenser serves to help increase the surge in the circuit. Maintenance of the coil is limited to keeping the insulating cap clean and dry so that short circuits and carbon tracking do not occur.

The distributor is of the four-cam type, with a single set of breaker points. The distributor camshaft rotates at a speed of one-half that of the crankshaft. The fiber block of the moveable breaker point should be lubricated periodically with lithium grease. In using the lubricant, care should be taken to ensure that no grease gets onto the contact points-only a small amount of grease should be used. The vacuum advance mechanism requires no maintenance, but should be checked periodically for leakage of the diaphragm. Sucking air from the vacuum tube should cause the interior of the distributor to rotate slightly. When air is sucked out and the tube blocked off, the interior plate of the distributor should not move from its advanced position until the air passage is opened.

The contact breaker points are adjusted as described in , and should have a clearance of 0.016 in. (0.41mm).

REMOVAL & INSTALLATION





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Fig. Fig. 2 If the engine was rotated while the distributor was removed, position the distributor shaft drive cam as shown for proper installation



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Fig. Fig. 3 The distributor drive cam is separated into two unequal sections by a drive slot



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Fig. Fig. 4 To remove the distributor, label the spark plug towers ...



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Fig. Fig. 5 ... and detach the spark plug wires from the cap



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Fig. Fig. 6 Unfasten the retaining clamps, then lift the distributor cap off of the distributor housing ...



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Fig. Fig. 7 ... and matchmark the rotor tip to the housing



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Fig. Fig. 8 Matchmark the distributor housing to the crankcase for proper positioning during installation



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Fig. Fig. 9 Loosen the distributor retaining clamp nut ...



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Fig. Fig. 10 ... then lift the distributor out of the engine

  1. Disconnect the negative battery cable.
  2.  
  3. Trace the No. 1 spark plug from the front right-hand cylinder (clinder No. 1) back to the distributor. Mark the position of the No. 1 cylinder spark plug cable terminal tower of the distributor cap on the distributor housing, so that when the cap is removed from the distributor the position of this terminal can be seen.
  4.  

Some distributors are equipped with a notch in the housing corresponding to the No. 1 cylinder terminal tower position, so a mark is not needed on these distributors.

  1. Label and disconnect all of the spark plug cables from the distributor cap. Disengage the retaining clamps and lift the cap off of the distributor housing.
  2.  
  3. Position the engine at Top Dead Center (TDC) on the compression stroke of the No. 1 cylinder, as follows:
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    1. Using a wrench on the drive belt pulley center bolt, turn the crankshaft until the TDC mark on the pulley is aligned with the timing mark on the engine (as explained in ).
    2.  
    3. Once the marks are aligned, look at the distributor rotor and determine if the contact end of the rotor is pointing toward the No. 1 terminal tower mark on the distributor housing. If the contact end of the rotor is aligned with the mark, the engine is at TDC, otherwise the crankshaft should be rotated an additional complete revolution (360 degrees) until the TDC pulley mark aligns with the engine timing mark again.
    4.  

  5. Matchmark the distributor housing with the engine block. Now the rotor-to-distributor housing and the distributor-to-engine relationships are marked for installation.
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  7. If equipped, label and disconnect the vacuum hose from the advance mechanism on the distributor. Label and detach the breaker point lead wire from the ignition coil.
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  9. Remove the distributor hold-down bracket nut or bolt, then lift the distributor up and out of the engine block.
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  11. Before doing anything else, look down into the distributor hole and note the orientation of the distributor drive slot. Note that the two areas separated by the drive slot are not equal: one is smaller in size than the other. Marking the direction of the slot on the engine block will greatly help installation if the crankshaft is turned while the distributor is removed.
  12.  

To install:

  1. If the crankshaft position was not disturbed (rotated or removed) while the distributor was removed, skip to Step 10, otherwise perform the following. Look down into the distributor hole and rotate the crankshaft until the drive slot is oriented in the same direction as indicated in Step 8. Once again, make sure that the small and large halves of the drive gear are positioned correctly.
  2.  
  3. Align the rotor and the No. 1 cylinder mark on the distributor housing, then slide the distributor into the engine block with the distributor-to-engine matchmarks also aligned. The distributor should slide completely into the engine block. If it does not, slightly turn the distributor rotor from side-to-side until the distributor settles completely into the engine. If the rotor requires a 180 degree rotation before the distributor will settle completely into the engine, the distributor should be removed and the crankshaft turned 360 degrees. The distributor should now fit into the engine correctly.
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  5. Install and tighten the hold-down nut or bolt and tighten it securely.
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  7. Attach the vacuum advance hose to the distributor.
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  9. Set the distributor cap onto the distributor housing and secure it in place with the two hold-down clamps.
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  11. Attach the spark plug cables to the distributor cap.
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  13. Attach the breaker point lead to the ignition coil.
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  15. Connect the negative battery cable.
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  17. Adjust the ignition timing as described in of this guide.
  18.  

DRIVE PINION REPLACEMENT



To remove the distributor driveshaft, loosen the distributor clamp bolt, turn the engine so that the rotor is pointing to the No. 1 cylinder (the notch on the distributor housing), lift out the distributor. Remove the fuel pump and the intermediate flange, gaskets, and fuel pump pushrod. Remove the distance spring on the distributor drive shaft. Be sure that the No. 1 cylinder is at its firing point, and withdraw the driveshaft via a removal tool by pulling with the extractor and turning the driveshaft to the left at the same time.

Remove the washer(s) under the driveshaft, being careful not to drop a washer into the crankcase. When the engine is installed, a magnet is handy for removing these washers.

When installing, the reverse of the previous procedure applies. The fuel pump pushrod drive eccentric and the pinion teeth should be checked for wear. If the teeth are badly worn, the teeth on the crankshaft should also be examined. Check the washer under the driveshaft for wear and replace them, if necessary. Position the No. 1 cylinder at its firing point and insert the distributor driveshaft.

The slot in the top of the distributor driveshaft has an offset slot which divides the top of the driveshaft into two unequal segments.

The driveshaft is installed as follows:

Engine

Distributor Driveshaft Installation (No. 1 Cylinder in Firing Position)

Type 1 and 2 (except early 1968 models with throttle positioner)

Slot at right angles to crankcase split, small segment toward the crankshaft pulley.

Type 3

Slot at about 60° to crankcase split, small segment toward oil cooler.

Insert the distance spring, install the distributor, set the ignition timing, and install the fuel pump.

When the engine has been completely disassembled, it is necessary that the oil pump, the fan housing, the fan, and the crankshaft pulley be installed before the distributor drive shaft is inserted.

 
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