With the cam position sensor similar to a distributor on the turbo models the procedure should call for the No.1 piston on its closed compression stroke and hence inhibit the engine from turning during the process of removal of the cam position sensor. Start by removing the negative terminal of the battery and pulling out the electrical connection of the sensor. For models from 1979 to 1982, vacuum advance unit hoses should be disconnected. First cylinder spark plug wire terminal should be found where there is a raised number "1" on the top of the distributor cap or starting from the number one spark plug wire. Take off the distributor cap and rotate the engine until the rotor comes to the position of the number one terminal to align the distributor with its preceding position using marks on the distributor base and the engine block. To replace it, you need to pull out the hold-down bolt and lift the distributor out, up or sideways; you dispose the old O-ring. For installation, if the crankshaft has moved, rotate the crank-shaft until number one piston is pushed back to TDC by rattling on the compression pressure. It is recommended that a new O-ring should be fitted to the sensor shaft and slid into the position inside the engine with its positioning in reference with the two marks made earlier. You may have to adjust the rotor on the engine block to match the facing of the camshaft gears, then put in the hold-down bolt until it is slightly tightened before putting the distributor cap back on. Connect the electrical connector back, secure any spark plug wires if necessary and then connect the negative terminal of the battery. Last of all, make sure the ignition timing is fine and twist the hold-down bolt to the extent it is supposed to be.
