Depending on whether your ignition system is the later factory electronic, or the standard early ignition, your spark plug connectors may be 1,000 ohm or 5,000 ohm. The early original 1,000 ohm resistor ends were all plastic. All original spark plug wires were solid stranded copper wire (tin coated). Original style wire could be ordered by the meter from the dealer at one time (part # 110 159 1818) The ends on the original sets, simply screw on or off and can be replaced. All spark plug connectors should be straight. If you have a right angle connector on #1 this is not correct but will work fine. MB carbureted engines of the era used a right angle connector at #1 because of the location of the distributor on the carbureted engine.
later spark plug connectors with factory transistorized ignitions .......... 5,000 ohms
earlier spark plug connector with standard ignitions .......................... 1,000 ohms
resistance of rotor....................................................................... 5,000 ohms
coil cable end at coil ................................................................... 1,000 ohms
coil cable end at distributor.......................................................... 1,000 ohms
Now if you are using the incorrect resistor spark plugs add 5,000 ohms resistance.
If you are using the incorrect resistor style spark plug wires add 5,000 ohms resistance.
The factory allows a total resistance from the coil end of the coil wire to the end of the spark plug of 13,000 ohms resistance ( early non-transistorized ignitions). You can measure the resistance of each component separately and add them on each cylinder if you like. 19,000 ohms total resistance is allowed on the latter cars with factory electronic ignitions. Or replace any one component which deviates more than 25% from specs.
You can also assume that if you are using more modern coils, or aftermarket transistorized ignition systems with much higher output voltage, then the 19,000 ohm total resistance figure can also apply to your earlier engines.
Example...If your are using resistor spark plugs, resistance carbon wires, then you are already out of factory specs on maximum resistance. (rotor 5,000 ohms + resistance spark plugs 5,000 ohms + resistance carble spark plug wires 5,000 ohms, etc, etc total 15,000 ohms +)
Ohm meters are inexpensive and easy to use. A resistance check on all ignition components should be conducted during a standard tune up or trouble shooting session.
