I believe I have this same difficulty with a '57 261 school bus engine (12V) in my '54 2-ton dump truck. It has had two new regulators installed and adjusted by the only well-reputed shop in the area, to ever-worsening effect. I would like to try your adjustment technique even though I fear I may not have the skills to do it properly.
I have only the service manual for the ’54 trucks, which are 6V. I don’t know if I could follow their directions for adjusting the air gap (for opening reverse-current purposes) and for setting the spring tension for closing voltage. Do you know if the 12V regulators are essentially the same as the 6V ones?
Also, you put in all capitals about an accurate ammeter. Where in the procedure does this enter? — in the 1-2 amps of reverse current? Actually, I don’t understand why the coil holds these points closed when the battery voltage equals that from the regulated generator, much less exceeding it to give a reverse current. Should the coil not just stop pulling when these are equal, letting whatever spring force pull them apart?
I constantly hear that these matters are “not rocket science”, but to me they’re not far from it. I actually am a rocket scientist and this technology is at my limits. Thanks for any help.
Clarke
