Greetings,
I’ve been lucky to find a 67 MGB, great shape little use over the past 15 years. I’ve probably drove it more the last month than the past 15-years. No issues at all for the 1st two-weeks when what I assume happened was my ignition system stayed live after I turned the ignition off (voltage regulator contact stuck closed?) and I suffered a major melt down.
1) generator severely fried
2) voltage regulator fried
3) wiring melt down of:
a. generator to regulator
b. regulator to starter solenoid
c. collateral damage of various wiring in harness
I replaced all the main components noted above and the damaged wiring. Performed exploratory surgery on the wiring harness within the damaged area and my conclusion was I’ve detected and replace all.
Go live after these repairs gave me two new problems:
1) 1st intermittent headlights and then no head lights
2) Ignition light remained on after the engine was running.
The head lights issue was really solve by replacing one light, but prior to that I
1) Replaced the head light switch with no success of repairing the light issue.
2) Inspected the head light wiring very closely for shorts.
The ignition light remaining on was solved when I finally managed to focus my 44-year old eyes closely enough on the wiring schematic to see that I had two wires at the voltage regulator reversed. These were the brown and yellow generator to voltage regulator wire and the brown and yellow ignition light to voltage regulator wire.
Swapped these to there correct post and thought I was laughing. Ran the car for a good afternoon trip, fired her up later that evening to find that the voltage regulator contact was sticking. Recognized this because the ignition light would stay on with the ignition off, and would not go on with the ignition turn to the on position prior to firing her up. Fire it up and the ignition light would go and stay on. By the way the afternoon trip I deduced later was not as good as I lead myself to believe because I was letting the joy of finally driving her lead me to ignore what I no believe was my generator frying itself. This happen during highway speeds at approx 70 MPH (and yes it has the large pulley on the generator not the small one).
Change the voltage regulator the next day with no results. That was when I disconnected both wires at the generator, fired her up and measured zero voltage from the generator.
Put another generator in it tonight, measured good voltage, ignition light off when running and took it for another ride. Just fired the second generator, once again only after some length of driving in the city, it fried at highway speed.
So; what the heck is going on.
Many thanks,
Tim