1937 Buick Voltage Regulator Conversion

[1937 Buick 66C]

1937 Buick Voltage Regulator Conversion; March, 2010

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The following diagram from the Nov., 1936 Buick Service manual for model year 1937 shows the factory wiring configuration for the original 5-pole voltage regulator. These voltage regulators were not used for an extended period by General Motors, and have been superseded by 3-pole voltage regulator. This document is intended to explain how to perform this conversion, without modification to the stock Buick wiring harness.

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IGNITION: On the five pole regulator this connection is energized with +6V when the ignition switch is turned on. This is the current source for the start circuit interrupter relay. When installing the three pole regulator, this wire is disconnected and capped with a wire nut. This wire is not used with the three pole regulator, and is live when the ignition is turned on. It is important that it be fully insulated and secured so it cannot short to ground.

GROUND: This connection provides the chassis ground signal to the starter solenoid. When installing a three-pole regulator, this wire is to be attached to one of the mounting screws of the new regulator such that it provides ground for the starter solenoid. The Buick starter solenoid is unique as it has a wired connection for both ground and +6V. The starter solenoid does not obtain ground connectivity from it’s physical connection to the engine block. If this wire is not securely connected to ground, the starter will not operate. If you are using the throttle start capability you need to be ABSOLUTELY CERTAIN that your vacuum start switch is operational and properly adjusted. If not, you run the risk that the starter will engage any time you press on the throttle even if the engine is already running.

BATTERY: This where the battery is connected to the voltage regulator, and how the charge from the generator is sent to the battery. On the three-wire regulator, this connection goes to the BATT pole. It is “hot” at all times that the battery is connected. The other end of this wire is attached to the ‘+’ battery cable through the sharing of the large ring connector on the starter.

FIELD: This is the field connection to the generator. On the three pole regulator, it connects to the corresponding FIELD pole. It is the only wire which should be attached to this pole.

GENERATOR: This is the armature connection which feeds power to the regulator which is ultimately used to charge the battery. On the three pole regular, this wire is attached to the “+” or “A” pole. It is the only wire which should be attached to this pole.

Why they are different: The original 5-pole voltage regulator contains a secondary relay (shown on the left of the diagram) which is closes when the ignition switch is turned on using the generator field as the ground source for the relay. When the generator begins producing current, the field is energized, no longer functions as ground and this relay opens. When the relay is open, the ground circuit to the starter solenoid is interrupted and the stater cannot be operated. This provides a second layer or protection to prevent the starter from engaging while the engine is running. The first layer of protection is the vacuum start switch on the intake manifold which interrupts the “+” signal to the starter solenoid when it’s contacts are opened by the presence of vacuum in the intake manifold.

Please feel free to contact me with any comments or corrections to this document.

Jon B Kanas

Longmont, CO

kanas@qadas.com

[Guest jules greenway]

Jon

that's a really useful explanation thanks

Jules

[Guest Sympletruth316]

Anyone still have this picture? I need some help to redo my wiring to the 5 pin regulator. I dont which of the top three wires go where in what order.

[1937 Buick 66C]

Anyone still have this picture? I need some help to redo my wiring to the 5 pin regulator. I dont which of the top three wires go where in what order.

I have it archived in my restoration records. Please email me directly at kanas<at>qadas.com and I'll respond with it. I'm not sure why it doesn't appear on the forum posting anymore.

Regards,

Jon

[startergenrebuilder]

I have it somewhere also. If Jon can't find his, let me know and I'll see if I can dig it up.

-Jason

[Guest Sympletruth316]

Got it, thank you

[Dave_B]

After reading some of the other recent threads covering this topic it might be a good idea to install a switch in the "GROUND" wire for the starter solenoid. There have been reports that in low manifold vacuum situations, hill climbing, passing, etc the starter will engage while the engine is running. This happens no matter how well the vacuum start switch is adjusted. A simple toggle switch under the dash would disconnect the solenoid ground wire and prevent the starter for going off when you don't want it to.

After starting the car flip the switch disconnecting the ground and no worries. Plus you get to keep your factory starter switch on your carb.

Dave

[Ben Bruce aka First Born]

After reading some of the other recent threads covering this topic it might be a good idea to install a switch in the "GROUND" wire for the starter solenoid. There have been reports that in low manifold vacuum situations, hill climbing, passing, etc the starter will engage while the engine is running. This happens no matter how well the vacuum start switch is adjusted. A simple toggle switch under the dash would disconnect the solenoid ground wire and prevent the starter for going off when you don't want it to.

After starting the car flip the switch disconnecting the ground and no worries. Plus you get to keep your factory starter switch on your carb.

Dave

Would work as a theft deterrent, also.

Enjoy

Ben

[MikeMike]

If you use a momentary push button switch

which you press and let go at the same time

as you press the accedlrator pedal . . .  :)

 

[DonMicheletti]

I did what MikeMike says on my Roadmaster. I did have the starter clash on very hard acceleration without it

[Gary W]

On 3/7/2010 at 11:30 PM, 1937 Buick 66C said:

This provides a second layer or protection to prevent the starter from engaging while the engine is running.

 

So, if you convert the original 5-pole VR to a newer 3-pole VR do you lose that second layer of protection?  Or is there another mechanism built in (aside from the vacuum) that prevents starting  the engine every time the accelerator pedal is depressed?

 

 

If you use a momentary push button switch

which you press and let go at the same time

as you press the accedlrator pedal . . .  

 

How about a momentary switch at the extreme of your clutch pedal?  Like the new cars, it makes sure your clutch pedal is fully depressed when you start and the accelerator pedal and clutch pedal are rarely depressed simultaneously so that eliminates the conflict.  Just thinking out loud.......

 

 

 

 

 

Edited December 14, 2018 by Gary W (see edit history)

[DonMicheletti]

Yes, you loose that second layer of protection.  Without that circuit you are relying on the vacuum cutout at the starter switch.

Actually, I find the clutch switch in my car a royal PITA.  I have been driving cars without is since I first started driving in 1957.

 

Just one more gimik so incompetents can drive without thinking.

 

[Morgan Wright]

I had a toyota with a clutch lockout switch. I wrapped duct tape around it so it was always on. No more problem.