Gary2
New member
Hello All:
I replaced my alternator and regulator about a year ago or so with the 1972 Datsun 510 parts from NAPA as recommended in this forum. The NAPA part numbers are 13-8002 for the alternator and VR521 for the regulator. After finding a short circuit in the fuse block and replacing it with a fuse holder that holds the modern type automotive fuses, the charging system has worked well. That is until several weeks ago when I noticed the voltmeter (aftermarket Sunpro) pegged out to the right. I placed a multimeter across the battery and it was reading 15 to 16 volts so I shut it down. Continuing to look for problems with the motor off I noticed that the factory instrument light bulbs were burned out. I replaced them and they burned out again when turning off the ignition switch (engine not running). They will light up as normal with the engine not running but as soon as I turn off the ignition switch, the bulbs burn out. Then, using the multimeter to check for a voltage spike when turning off the ignition, I was shocked with a voltage that felt like something I use to get from my old lawn mower. The voltage does not register on my old analog voltmeter.
After talking with several people, some think that the increased voltage could only be generated by a coil and that there may be a diode that is not functioning. A local alternator remanufacture checked the alternator and said it was ok. I installed a new regulator and still have the same conditions, high voltage during the engine operation and instrument lights burning out when the ignition switch is turned off when the engine is not running.
Checking for short circuits I have stripped the wiring harness down to single wires and looked over all the wiring. The only way I can get the instrument lights not to blow during ignition shut off is to turn on the head lights or disconnect the two prong plug going to the alternator with poles labeled N & F or disconnect the regulator.
Has anyone experienced this sort of problem? Am I using the right alternator or regulator? This is a great forum and I have learned a lot of good information from all the experience out there. I am considering adapting a Delco one wire alternator to the tractor if I cannot figure it out.
Any help would be greatly appreciated, thanks Gary
I replaced my alternator and regulator about a year ago or so with the 1972 Datsun 510 parts from NAPA as recommended in this forum. The NAPA part numbers are 13-8002 for the alternator and VR521 for the regulator. After finding a short circuit in the fuse block and replacing it with a fuse holder that holds the modern type automotive fuses, the charging system has worked well. That is until several weeks ago when I noticed the voltmeter (aftermarket Sunpro) pegged out to the right. I placed a multimeter across the battery and it was reading 15 to 16 volts so I shut it down. Continuing to look for problems with the motor off I noticed that the factory instrument light bulbs were burned out. I replaced them and they burned out again when turning off the ignition switch (engine not running). They will light up as normal with the engine not running but as soon as I turn off the ignition switch, the bulbs burn out. Then, using the multimeter to check for a voltage spike when turning off the ignition, I was shocked with a voltage that felt like something I use to get from my old lawn mower. The voltage does not register on my old analog voltmeter.
After talking with several people, some think that the increased voltage could only be generated by a coil and that there may be a diode that is not functioning. A local alternator remanufacture checked the alternator and said it was ok. I installed a new regulator and still have the same conditions, high voltage during the engine operation and instrument lights burning out when the ignition switch is turned off when the engine is not running.
Checking for short circuits I have stripped the wiring harness down to single wires and looked over all the wiring. The only way I can get the instrument lights not to blow during ignition shut off is to turn on the head lights or disconnect the two prong plug going to the alternator with poles labeled N & F or disconnect the regulator.
Has anyone experienced this sort of problem? Am I using the right alternator or regulator? This is a great forum and I have learned a lot of good information from all the experience out there. I am considering adapting a Delco one wire alternator to the tractor if I cannot figure it out.
Any help would be greatly appreciated, thanks Gary