1916 Buick Wiring Question

[redbaron1930]

Hi;

 My 1916 Buick D-45 seems to be wired with some kind of relay (not stock I'm sure) which connects the generator circuit to the ampmeter (opposite the battery wire) when the ignition switch is turned on. From looking at wiring diagrams it appears that Buick connected the generator output directly to the ignition switch. I understand the need to disconnect the generator output when the car is off. So it seems to me that the purpose of putting this relay in would be to stop all the generator current from going through the ignition switch. I have to rewire the car and would like to bring it back to original. My question is, is there an issue with the original way Buick did it by running the generator output through the ignition switch, or is it OK? Also what is the wire gauge for the generator and battery wires?

 

  Thanks

           Andy

[Oldtech]

I think what you are looking at is their idea of overcurrent protection. If the load gets too high the magnet pulls the contacts open and it starts buzzing. These were commonly bypased if they gave issues, so check your wiring diagram. There is no cutout. The ignition switch puts the power to the s/g to motor it, and therby connects the generator. IT only disconnects it when you shut it off. 

Edited November 7, 2023 by Oldtech (see edit history)

[redbaron1930]

40 minutes ago, Oldtech said:

I think what you are looking at is their idea of overcurrent protection. If the load gets too high the magnet pulls the contacts open and it starts buzzing. These were commonly bypased if they gave issues, so check your wiring diagram. There is no cutout. The ignition switch puts the power to the s/g to motor it, and therby connects the generator. IT only disconnects it when you shut it off. 

 Wiring diagram shows a circuit breaker protecting the lighting wiring. This is not wired that way, although the label in the back does sat "lights" and not "gen", but it also contains a ground wire not shown in the diagram, so I'm still not sure if it is original or not.

[Oldtech]

Post us a picture.

[Larry Schramm]

On 11/7/2023 at 12:12 PM, redbaron1930 said:

 Wiring diagram shows a circuit breaker protecting the lighting wiring. This is not wired that way, although the label in the back does sat "lights" and not "gen", but it also contains a ground wire not shown in the diagram, so I'm still not sure if it is original or not.

 

Do you have a wiring diagram for your car?

 

[Brian_Heil]

https://www.dezosmanuals.com/wp-content/uploads/2021/07/1916-Buick-Delco-Instruction-Book.pdf

[redbaron1930]

Brian;

  Thanks you for delco manual. I did have have a wiring diagram but this manual contains alot more information. I will have to look closer at the switch panel to see if the circuit breaker is in there. At this point it looks like the relay was added by someone so that the generator current does not pass through the ignition switch (I'm not sure why they felt this was a problem.

 

  Thanks

           Andy

[redbaron1930]

So I did a bit more homework, and what was put in was a GM headlight relay (probably used in the 40"s-50's). I was wired to the generator circuit to be closed when the ignition switch was turned on. My guess is it is not rated for the proper current because a copper bar was put in place of the fuse. So most likely I will do away with it and return the wiring to original configuration.

[27donb]

5 hours ago, redbaron1930 said:

Brian;

  Thanks you for delco manual. I did have have a wiring diagram but this manual contains alot more information. I will have to look closer at the switch panel to see if the circuit breaker is in there. At this point it looks like the relay was added by someone so that the generator current does not pass through the ignition switch (I'm not sure why they felt this was a problem.

 

  Thanks

           Andy

 

I don't know how the 1916 is different, but my understanding of how the starter generator works is the motoring is required to turn the starter gear, so that it will engage in the reduction gears and the flywheel. 

 

Once the engine is running, disconnecting the ignition only, the generator will still produce power to the system, unless the ignition and motoring terminals are separated (two separate connections, even though both are connected to the battery source).  In theory, if they are not separated, the generator will back feed to the ignition wire, keeping the coil powered, and the engine will not turn off.  Theoretically.  I have never experienced it, but it makes sense.

 

Maybe that's why a relay was used, to give good strong motoring of the S/G for startup, and disconnect that circuit from the coil circuit so the above scenario won't occur and the engine will indeed turn off when the switch is moved to off. 

 

[redbaron1930]

35 minutes ago, 27donb said:

 

I don't know how the 1916 is different, but my understanding of how the starter generator works is the motoring is required to turn the starter gear, so that it will engage in the reduction gears and the flywheel. 

 

Once the engine is running, disconnecting the ignition only, the generator will still produce power to the system, unless the ignition and motoring terminals are separated (two separate connections, even though both are connected to the battery source).  In theory, if they are not separated, the generator will back feed to the ignition wire, keeping the coil powered, and the engine will not turn off.  Theoretically.  I have never experienced it, but it makes sense.

 

Maybe that's why a relay was used, to give good strong motoring of the S/G for startup, and disconnect that circuit from the coil circuit so the above scenario won't occur and the engine will indeed turn off when the switch is moved to off. 

 

Interesting point! The schematic showes separate connections to the ignition switch, so the circuit between the coil and gen. is broken when the switch is opened. This begs the question, is something wrong with my ignition switch or was it changed at some point to one with only one contact. More investigation needed!

[Oldtech]

Your observations are correct ign is disconnected by the switch. Unless your switch assembly has been messed with it should work as per diagram.

 

[redbaron1930]

Just an update on this, as it turns out the switch that is in the car now is a makeshift switch that used the original ammeter but 4 small commercial push pull switches. I have a 1917 parts car that has the original switch as shown in the delco manual that Brian shared. I will use this switch and restore the car to its original wiring as shown in the schematics.........Mystery Solved!

  Thanks to all for all your help!

                          Andy

[Oldtech]

Ahhh. There's an explanation!.