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Delco 1920 Starter/Generator question

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Jerry, not at all upset with you. Not in the slightest. The S/G is driving me nuts. My Cadillac manual shows a 1919 Cad with Type 57. I have a 1920 with a Type 59.  The 1919 ignition switch diagram is different. I have the AACA Library sending me Type 59 Service Bulletins. 


The whole s/g is a very simple device, yet I cannot find the key. I keep thinking I have an answer, but no joy. I have talked with a couple of old car people who will bench test the S/G. So, I will pull the damn thing and take it to them.

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Bill , am I mistaken in thinking you had the same problem before the rebuild ? In which case , it would make the switch suspect , correct ? Have you been talking to Romaine ? Hard to imagine they would have made a mistake , ( but maybe there is some quantum explanation tied up in another dimension as per above speculation ). Yeah , what does Romaine say before you yank the thing out again ? After all , they know how to bench test it , and did so , right ? As I say , it would seem that if the problem existed before and after the rebuild , the fault would logically lie elsewhere. Unless Romaine doesn't know what they are doing. Not likely. I am very curious.  - Carl

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On ‎10‎/‎29‎/‎2016 at 6:57 PM, Bill Caddyshack said:

Latest symptoms. 


When I turn on the ignition switch, nothing, if I depress the starter pedal I can hear the armature turning, but will not engage. Does not spin the shaft connected to the distributor. I assume it should not, I guess that once the engine is running, the ratcheting clutch allows the armature and operate as a generator instead of a starter.


As the armature spins the Ammeter does indicate a very small low draw.


Somehow is wired wrong. I suppose the armature should only be spinning as it is should only be doing so when only the ignition switch is engaged. At least that part is working, albeit the switching somehow it is improperly connected.


Ok, ok. It would seem the process is that it SHOULD work would be,


1. The ignition switch is turned on. The armature spins, like it is doing.

2. Depress the pedal and the bendix engages the starter drive and the flywheel thereby starting the car.


Best I can tell, the brushes and spring are good. Everything looks right. I am certain that the wires connecting the s/g from the ignition (combination switch) are correct. Something inside the s/g is not wired as it should be. Please look at the enclosed diagrams.




Please have a look at the enclosed diagrams.

IMG_0473 (Large).JPG

IMG_0475 (Large).JPG





I do not know where you got the wiring diagram that you think is for your car, but if it is a Buick I believe it is incorrect.  It shows an 8 cylinder engine. All Buicks that I know of have always had a negative ground.


Below is a wiring diagram that I believe is for your car if it is a 1920 Buick 6 cylinder.  If not, let me know the exact model and year and I will scan the correct for you if I have it in my book.  You will note that it is a negative ground for a 1920 Buick.



wiring diagram2082.pdf

wiring diagram2083.jpg

Edited by Larry Schramm (see edit history)
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  • 4 months later...

This thread has inspired me to get into my 24-45 starter generator.  The generator commutator is very dark and  worn, so I removed it to turn it and clean up the starter one as well with emery cloth.  Before I began, the generator motored on the bench and the starter seemed to spin strong too. 


1 - My question is about the ratcheting clutch.  It seemed fine on the bench, but I had trouble getting it off the shaft and when it was off, it was stuck.  I got it freed up, but my question is about the spring loaded plungers.  I see two of them, but they seem to have a flat top with a hole in them?  Am I missing some parts, or is that all that is supposed to be there.  Is there supposed to be a check ball or something along with the plunger?  I can get the clutch out of the gear, but I cannot disassemble the clutch itself.


When I reinstalled the clutch and gear on a spare S/G shaft, it rotates freely and quietly in one direction, and locks up in the other, so that seems normal.


Just don't want to get it all on the car, and then find out there should be check balls or something else in the clutch, that may have dropped out on the floor...

040117 buick 24-45 starter generator (1).JPG

040117 buick 24-45 starter generator (7).JPG

040117 buick 24-45 starter generator (14).JPG


2 - In the wiring diagram, one wire goes from the ignition switch to one motoring terminal, the other motoring terminal gets it's 6 volts from the coil + terminal.  During bench testing, I just gave 6 volts to both motoring terminals and it worked.  Why does the second motoring terminal have to be connected to the coil +?  Couldn't both motoring terminals just get their 6 volts from the ignition switch?




Edited by 27donb
added another question (see edit history)
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Thanks for posting on this topic. I will be interested in some responses. On my 1925-25 the starter pedal engages very smoothly and no grinding.  On my 1925-45 Master I really have to "MASH" down on the starter plunger to keep engagement or it grinds very easily.To me that would not seem normal. Leif Holmberg is sending me scans of the 1925 Master Book of Parts so I will have a better Idea of how the plunger set up is supposed to look as opposed to the standard pedal arrangement.

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