I just installed a newly rebuild correct 68 1100704 37A alternator from a very reliable builder. I hooked up my timing light with build in voltage and it is reading 14.9-15v. No load and not warmed up. Should I just run it a little while and see if it drops some?
That’s high sounds like you charging at full field voltage Is your battery low You don’t have any electronic things like hei distributor fuel injection Etc That high voltage could hurt the electronics or over charge and boil the battery
Service manual 6E-38 states normal regulator voltage range is 13.5-16v. So I guess we are good. Just surprised me when I removed one good alternator charging around 13.6 V that this new alternator went to 14.9
Service manual 6E-38 states normal regulator voltage range is 13.5-16v. So I guess we are good. Just surprised me when I removed one good alternator charging around 13.6 V that this new alternator went to 14.9
Sounds like the voltage is right where it should be. A 12 volt system should charge at 14.8 volts +/-. I would be worried if it was anything other than 14.8 volts, plus or minus a tad. The voltage was taken at the battery? Did you check it with another multimeter? The voltmeter on the timing light will have an accuracy factor of a few %. I take it your car is completely stock, if so the voltage sensing wire is connected to the voltage regulator through a fusible link to the main splice. The main splice connects the red B+ wire from the alternator, the red charging wire to the battery, the volt sensing wire to the voltage regulator and the system power up wire to the horn relay. Any voltage draw downstream from the horn relay, brake lights, radio, ignition, etc. is sensed by the voltage regulator. The voltage regulator will then up the output of the alternator to keep the voltage at the main splice at 14.8 volts. The voltage regulator should have kept the voltage at the main splice at the exact same voltage with the old alternator as it is now keeping the voltage with the new alternator. Perhaps the old alternator was defective, or perhaps when changing the alternators you cleaned up some terminals to get a higher reading? Did you check the old alternator with the same volt meter equipped timing light?
Sounds like the voltage is right where it should be. A 12 volt system should charge at 14.8 volts +/-. I would be worried if it was anything other than 14.8 volts, plus or minus a tad. The voltage was taken at the battery? - Yes
Did you check it with another multimeter? The voltmeter on the timing light will have an accuracy factor of a few %. - No but can do that tonight.
I take it your car is completely stock, if so the voltage sensing wire is connected to the voltage regulator through a fusible link to the main splice. The main splice connects the red B+ wire from the alternator, the red charging wire to the battery, the volt sensing wire to the voltage regulator and the system power up wire to the horn relay. Any voltage draw downstream from the horn relay, brake lights, radio, ignition, etc. is sensed by the voltage regulator. The voltage regulator will then up the output of the alternator to keep the voltage at the main splice at 14.8 volts. - I had the radio on which I did not when I was connected to the old Alternator.
The voltage regulator should have kept the voltage at the main splice at the exact same voltage with the old alternator as it is now keeping the voltage with the new alternator. Perhaps the old alternator was defective, or perhaps when changing the alternators you cleaned up some terminals to get a higher reading?
Did you check the old alternator with the same volt meter equipped timing light? I remembering seeing it but during the time I was focused on setting the timing and did not really pay attention to it. I kind of think it was < 14v maybe 13.6 or so. Also the old alternator was a 55A if that would make a difference.
I could reinstall the old alternator and get a reading if you think I should. But it sounds like it is doing what it should and I should not worry?
Also, I changed the belts to the correct style from the modern ribbed, also could a tighter belt give more voltage?
I think you should close the hood and be happy you have an electrical charging system that is putting out what it's supposed to. Next time you have a battery on a battery charger, check the voltage. I will most likely charge at >14 volts.
Hah! Took me a while to find the ' > ', never used that one on a keyboard before.
I have a INNOVA Pro Digital Timing Light (DIS) should be a pretty good source of a votage meter. But I do have a couple other DVOM I can try.
This is the reason I ask. I replaced my voltage regulator with a solid state unit and watched as voltage climbed past 20 volts.
I hooked up another cheap harbor freight meter I had laying in my toolbox and you can see the difference - Problem was, the battery in the other meter was almost dead.
Tested a few voltages meters and they were all the same.
I then tried a correct rebuild old style regulator and the voltage dropped to 14.1 and then after running for a few min it settled down to 13.7-13.9v.
Are there any disadvantages using a old style vs new style regulator. The new style I have is an expensive USA 519 The old style is date correct and would rather use it if they work good.
