ALTERNATOR AND CHARGING SYSTEM
Here is another little tip I came across this month when I was changing my Midget from a Lucas alternator (which gave out at the slalom and I had to drive home in the dark) to a GM Delco unit. When installing a new alternator or battery, make sure the battery is fully charged. The alternator was never designed to charge a flat battery in the car. Use a battery charger to bring the battery up 12.7 Volts. Use your multimeter to test this with the car not running. Start the car and run it a 2000 RPM. Test the alternator output by using the multimeter between the Positive battery terminal and a ground. You should get a voltage between 12.7 and 14.5 volts. Now create an electrical load by turning on the lights, heater fan and whatever else your car has. The voltage should remain close to the no load reading.
Also check the condition of the battery connections. The connections should be clean and tight. If they are corroded you should replace the entire battery cable, not just the end. You should also check the condition of all ground straps. They must clean and tight and especially with an MG, not grounded to rust!
Here is another fault test that you should perform. If the key is on, engine stopped and the indicator lamp does not light! Do a test of the dash board light, disconnect the wire from the alternator to the lamp and connect it a ground. Turn the ignition on and the lamp should light. If it doesn’t, the lamp or wire is faulty and should be repaired. If it does light the alternator is faulty and further tests as described above should be performed.
The final task to finish my install is to contact Len Drake and order a Lucas label to put on my Chevrolet alternator. If you are a purist and have a Lucas alternator that isn’t performing, ROKO Auto Electric in Vernon can rebuild it for you. The cost should be $120 to $150 depending on the model. They actually had a rebuilt one for my car in stock, which I found out after I modified the mount to accept the Chevy unit.