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1925 Buick starter motor-generator


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Ken,   Note #3.  Think about the theory behind all this in slow motion.  The starter generator is motoring or turning slowly.  The pedal goes down slightly - I assume (but don't know)  that the flywheel is engaged first, or the pinion engages first - maybe simultaneously.   That is when the light ticking is heard.  A little more distance on the slider and all the gears should be engaged.  Then it is straight sliding until you get good teeth contact.  During this slide, the generator brushes should be lifted.   At the end of the slide, the brushes should make contact for the starter.  With the battery disconnected, and the SG cover off,  and the starter pedal return spring unit removed, you should be able to watch all this happen.   Hugh

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Hugh - 

 

The gear count on the pinion is correct. 13 teeth and the diameter is smaller than the larger 12 tooth Master pinion gear. I am pretty confident that I have the correct pinion for the Standard. Good point that perhaps the Master pinion was originally used and damaged the starting sliding gear. Although when you match up the damaged sliding gear the shape fits the standard teeth. The troubling thing is the 13 tooth pinion gear turns the engine with the damaged starter gear but not with the undamaged starter gear. Both starter gears are the same other than the damaged area.

 

The concentric cones that hold the starter look correct. I can double check these next week. It seems that you can only put these cones  in one way and they should self-align. I’ll make sure they are installed correctly. Easy to check.

 

With the battery disconnected the gears meshed easily and smoothly. I did have to align the starter gear by hand first since the pinion gear was not motoring with the battery disconnected. That is the other thing that is so baffling. The replacement gears mesh just as smooth as the damaged gear. When I was testing the slide it work smoothly in both directions. However, one thing I didn’t mention was one time when I tried to start it with the undamaged gear the positive cable where it attaches to the starter begin to smoke. I turned off the ignition and was able to quickly remove the positive cable from the battery since i didn’t have it tight on the post. I don’t think it damaged anything. I put the damaged gear back on and all seemed to work okay. I really won’t know if anything was damaged until I try it a few more times. I think what happened was the undamaged gear did not slide back all the way so the pedal must have acted as if it was depressed just a tiny bit.  I just don’t know what happened or why the pedal didn’t return all the way. The only thing I can think of is the undamaged gear was binding in the pinion gear. The other possibility is the safety wire I put on the hold down bolt for the fork that moves the sliding gear assembly. I wrapped the safety wire around the fork shaft and then through the hole in the top of the bolt. Perhaps the wire was in just the right spot to prevent the fork from sliding back all the way. I am just guessing. I really don’t know if this is what caused it to stick. I think i will remove the safety wire and just put some thread lock on the bolt. Did you safety wire this bolt? Hope my starter armature isn’t damaged 😃

 

I am going to have my friend slowly press the starter peddle down with the battery disconnected and make sure the process is proceeding as you describe above.

 

I did find the negative ground cable a little loose. I cleaned all the battery cables and put a charger on the battery. So maybe after it is charged up and the cables are cleaned it will turn over.  I’ll give it another try next week.

 

Ken

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I wonder if someone

- installed incorrect starter generator brushes or

- bent the SG brush holders where they are engaging or disengaging at the wrong time.

What is the condition of the 2 insulators.  - The one that the pointer goes into that drops the Starter brushes, and the one on the little fork that lifts the generator brushes.  

The order would be to fix and adjust all the mechanical parts, then investigate the timing of when the electrical operation occurs - When do the generator brushes lift, and when do the starter brushes engage.  

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Hugh.

 

I finally got it working! Gears sound good without any loud noise when they engage.The armature shows no sign of damage. It pulls about 300 amps when the brushes drop on the starter which seems reasonable. I pulled the sliding gear and regreased the clutch but I don't think that was my problem. The ground cable was loose so there probably was not enough amps to spin the starter. Works fine after charging the battery and tightening the ground cable. Now I need to adjust the 3rd brush and tweak the timing a little and should be good.

 

Thanks for all your help and insight.

Ken

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Ken, 

     I needed to make the barrel that fits under the spring that holds the distributor down.  Mine came out of a rusty parts car.  No one sees it either - but I know it's there.  I needed one for my engine and one for my spare SG unit.  It did not take me much longer to make 3.  I silver soldered a 1/2" tall piece of 1/2" steel tubing to a #10 flat washer.  ID and OD matched surprisingly to the original.  I am dropping yours in the mail.    Hugh 

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