When I took my 914-6 out for a spin yesterday, I noticed that the voltmeter was only reading 12 volts instead of the usual 14 volts. The generator light was lit upon initial startup, but went out as soon as the alternator energized and then stayed off throughout the drive.

I am surrently using an aftermarket transistorized voltage regulator, but kept my original Bosch can regulator. Does anyone have information on how to check the voltage regulator function. I've used some very fine sandpaper to clean the points, but don't know if anyone has the info on adjusting the opening and closing voltages.

There is a procedure posted by another member on here where you remove the VR and short two pins together on the VR connector, then start the car and check the voltage at the battery,
This shows if your alternator is capable of putting out more voltage than is required (it will go to ~16 Volts).

If that step shows the alternator is OK, then it points towards the VR as having a problem (or something else).

If those steps dont get posted I will dig through my notes for them.

I dont know of any way to adjust the voltage in the old regulators.
It likely would be the compression value of the springs.
In the solid state versions it would be as simple as adjusting a resistor value, but those are likely potted and effectively tamper proof.

There has been discussions about the new voltage regulators not lasting very long. The Bosch ones that are in the $100 + range seem to hold up the best. The Hella and other $35 ones not so good.

That's what I wondered as I had replaced the old voltage regulator with the aftermarket one last year.

Hey George
I drove my car occasionally for two years not knowing that my alternator was not charging. My Optima battery sometimes needed to be charged but I thought it was from sitting for long periods.
The charge lamp worked and would go out above idle.
I finally discovered the no charge situation and removed the alternator (what fun!.... especially on a 6 !) and found the brushes were not making good contact on the armature due to a grey foreign material on the armature contacts.
The rebuilder was honest and told me the issue.
Cleaned, installed, no problem. 13.8V !

I really hope it's not the alternator as it truly is a pain to R&R on a 914-6. If it gets to that point, it might be time to pull the engine/transmission out and do a proper cleaning/reselling/etc. makes for a good time to adjust the valves as well.

I'll try the simple fixes first, but like you, I keep the car on a Battery Tender when it's not in use.

The GEN light only lights when the primary circuit which charges the battery and powers all the electrics on the vehicle and the secondary circuit which powers the voltage regulator are different.

If the primary and secondary voltages are the same the GEN light will not light. So if your VR voltage is low the GEN light will not light up.

The old-style points based regulators could be adjusted by bending the arms that the points were on. I don't know which way, which arm, etc., I have just heard that was how it was done.

--DD