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Delco 1920 Starter/Generator question


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Delco 1920 Starter/Generator question. When you step on the starter pedal, it feels as though it is blocked. Doing it several times, sometimes it works easily. I have rebuilt the s/g new brushes, bearings, rewound armature. Lubrication is correct. The hollow shaft where the bendix gear moves. Everything seems ok.

When the pedal works, it does so easily. Otherwise it completely blocks. Seems like the teeth are hitting each other stopping from meshing. Other times is does mesh. 

 

I did try to rock the engine with the trans in gear. See if it would  realign the starter gears. The engine moved enough to move the flywheel. No success.

 

Wonder if the alignment is off. Could the gears are blocking. Been suggested I shim the s/g 

 

Any ideas?

Edited by Bill Caddyshack (see edit history)
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Bill,  Is this with the ignition on and the s/g motoring ( turning ).    That is the reason for the s/g to turn when the ignition is on, to align the s/g gears with the flywheel gear.  Without the s/g motoring,  it will lock up.  The s/g on my 25 is not motoring properly and I have to turn the engine over a little  with the crank so the s/g gears will mesh with the flywheel.

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On 10/22/2016 at 8:35 PM, ROD W said:

Bill,  Is this with the ignition on and the s/g motoring ( turning ).    That is the reason for the s/g to turn when the ignition is on, to align the s/g gears with the flywheel gear.  Without the s/g motoring,  it will lock up.  The s/g on my 25 is not motoring properly and I have to turn the engine over a little  with the crank so the s/g gears will mesh with the flywheel.

 

Don't have a crank. 

 

It does start the engine when I step on the starter, when it engages.

 

Hmm, Nothing when I turn on the ignition switch. I did rebuild the s/g. Maybe I have a wire incorrectly connected? Is there a manual explaining the s/g schematic?

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Bill,  you may just have poor contact with the brushes that make contact with the communtator level of the armature that acts as the generator and which should cause the armature to rotate slowly when the ignition switch is turned on.  You should also see a positive charge on your gauge when the motor is running. If none of that is happening check the brushes to make sure they are making good contact and are not dirty/oily.  Spring tension may not be strong enough for good contact.  It is necessary to have that initial rotation to enable the starter gear to engage.    Leon

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Thanks for your additional help. Been busy the last few days replacing exhaust manifold gaskets on my 1933 Packard. Adjusting the valves and some tuning. Obviously longer in taking the time I had planned! <grin> Having to replace a few studs. and then will get on the starter / generator on our 1920 Cadillac. 

 

Thank you again! Will let you know on the s/g, using your ideas!

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All are correct above.  I might also add that if the unit is not 'motoring'  when you flip on the ignition, more than likely you are not making any charge either.  The clutch design was such that they 'clicked' (ratcheted) up thru 1922 and then went to a silent (sprag) clutch in 1923.  In the case of my '23 the two (no motoring no charging)  always happened together.  My issue was a commutator so worn and brushes so worn that there was not enough spring force left to keep the brushes in good contact with the commutator.  New (longer) brushes were not enough to fix the issue, I had to get a new armature/commutator assembly with a larger (not worn down to the size of a spool of thread) commutator.  I had the whole unit rebuilt by Jason at AER due to this.  He has been mentioned many times on this sight.

Edited by Brian_Heil (see edit history)
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Note that Bill had his S/G rebuilt (Romaine). He had the problem before the rebuild also. Sounds like a wiring or internal switch issue. Also , in the Cadillac S/G , the clicking was heard through 1925. Separate starters and generators began in 1926.   - Carl

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The problem is the wiring is incorrect. The communtators were in good shape, not ground down to thinmbles! :) 

 

I am pretty sure that the wiring is the problem. The Shop Manual is not exactly clear about schematics. I remember when having the s/g apart, there were large brushes at both ends (good and spring tension - I think). It seems the rear end is where the starter brushes work there by a tapered cylinder, when the pedal is depressed allow the starter brushes do engage.

 

So I guess that the generator brushes are on the front of the s/g. Not sure I remember if there are "extra set of brushes" in the front of the s/g. Am I to assume that the brushes in the front spin the connecting shaft from the s/g, that goes under the carb, to the distributor, and the shaft should be spinning when the ignition switch is on?

 

It made a loud sound when spinning, when I first got the car. This loud spinning is not audible when the ignition switch is on, but when the starter does work, I do have the same "spinning sound" I used to hear when the ignition switch was engaged - before depressing the starter pedal.

 

Ratcheting clutch seems good. 

 

Sorry for the confusing dialog. Not sure how to better explain. Would appreciate schematics for wiring. I have heard there is something called "Dykes Manual" that has a lot of info about early gasoline engines. If someone has a link????? Thanks

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Bill,  I don,t know if Cadillac used the same s/g as Buick .   the Buick s/g has both sets of brushes side by side at the rear of the s/g.  If you can not hear the s/g motor turning when the ignition switch is turned on,  maybe it is a fault in the switch.  Does the amp gauge show a discharge  -ve when the ignition switch is turned on and is charging when the engine is running.

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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

IMG_0477.JPG

Edited by Bill Caddyshack (see edit history)
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Bill,

 

"When I turn on the ignition switch, nothing,..."

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

 

Which is it??? Is doing "nothing", or is it spinning with ignition on???

 

Also, we are coming at this from the perspective of Buick owners. Maybe Cadillacs are different. In a Buick, the following occurs;

 

1. Ignition switch "ON"

2. S/G begins to rotate, (i.e. motors). At this point, generator brushes are in contact & starter brushes are lifted.

3. Push in starter pedal/button.

4. Starting gears begin to engage, aided by the rotation of the S/G unit.

5. As the starter pedal is further depressed and after the gears are engaged, the generator brushes lift up and the starter brushes engage.

6. The S/G is now in the starter mode and begins to crank the engine.

7. When the engine starts, the starter pedal is released, causing the starter brushes to lift and the generator brushes to engage and the starting gears to disengage.

8. Upon starting, the side shaft that drives the generator & distributor begins to rotate faster than the S/G unit, causing an overriding clutch to engage.

9. The side shaft now spins the S/G unit, which is in generator mode.

 

MAYBE with a Cadillac, the rotating, (motoring), only begins AFTER the starter pedal is depressed and BEFORE the starting gears engage, rather than simply when the ignition is turned on???

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Yes, the same proceedure. I am back to square one. The armature does not spin when the ignition switch is on. WHY? 

 

The gear teeth bump into one another, sometimes I can get the car to start by rocking it in gear first.

 

The wring seems correct, brushes correct, spring tension correct. the s/g looks great. Looks about new. 

 

Is there a really good schematic for Buick I can see??? Somewhere something is incorrect. Just can't find it!

Edited by Bill Caddyshack (see edit history)
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4 hours ago, JerryVan said:

If I interpret the wiring diagram correctly, it looks like, with the ignition switch "ON", you should show power from terminal #4, on your S/G, to ground.

 

Ignition switch seems to get it's power (in) from #4. What do you mean about "on your s/g, to ground"? We are working with a 6v positive ground system. 

 

In your second question, when it starts, i did not check the ammeter. Will do next time it starts.

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Bill

S-G "motoring" mode can be checked independently of ignition switch and associated wiring by carefully jumpering from the hot lug to both terminals A & F on the S-G unit. The front Generator lift brush (Armature) should have a wire running to the A terminal; F terminal should be connected to the nearest wire protruding out of the Field coil winding.  The unmarked rear terminal, which is visible but out of reach, connects the other Field coil with a wire leading to the rear movable Generator brush.

If all the connections are clean and no faults, it should work, and the problem is with the wiring or switch.  Both A & F terminals lead to the ignition switch, identified by 2 & 3 on this version of wiring diagram.

Kevin

S-G operation.jpg

wire diagram.jpg

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Bill,

 

What I mean is, with the ignition "ON", put one lead of your voltmeter on the #4 terminal of your starter generator and the other lead to ground. This will tell you if the starter generator is even getting the 6V it needs to motor. Once again, if I'm interpreting the diagram correctly. (Doesn't matter if it's positive ground or not.)

 

 

Capture.JPG

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Kevin, Your drawings are slightly different than mine. Are your terminals are in the rear of the s/g? I tried jumping both with hot and just got a large spark. I will post pictures of my s/g, also the back of my ignition switch.

 

FWIW The amp meter does not show a charge. It does show a discharge when I turn on the ignition switch and a greater draw with the starter engaged. 

 

I did start the car by putting it in 3rd gear and rock the car back and forth, the gears starter/bendix/flywheel meshed and the starter started very well using the pedal. Armature still does not spin. The car is running very well. I was able to drive about 30 miles today. Yay!  

Jason. I will try both diagrams tomorrow. 

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Bill,  we still haven't heard if the unit is charging when the engine is running???  Did you check that while on your drive.  I ask because I had a similar  problem with my 25-45 several years ago while on a lengthy road trip.  The s/g would not rotate with the ignition  switch on and I had trouble engaging the starter.  It also wasn't charging.  Turned out my armature failed  in the generator portion and I had to located a good one, not easy to find.  You might want to check with who rebuilt the s/g to confirm that the armature was checked with a growler and that all the windings were in good shape.  Leon

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The s/g is not showing a positive charge.

 

The two terminals on the front of the s/g (#3 and #4) are hot ALL the time! They are hot even when the  the wires are NOT connected. Could something be back-feeding from the s/q?

 

The starter does work when the pedal pressure if I rock the car enough to engage the bendix. Otherwise the bendix is blocked by the teeth. 

 

My original problem cam from the bendix was not lubricated on the sliding shaft causing the bendix not able to disengage from the flywheel, causing the armature to be spun at a high rate of speed, throwing out the winding wires. Romaine did a very good job rewinding it. They tested to be sure the starter and the generator functions were correct and operational.

 

I did have the wiring in some configuration and the s/g did spin, not when the ignition switch was connected, but only when I stepped the pedal. But, then the starter motor would engage. The pedal would make the s/g spin, but would not engage the starter! 

 

The ratcheting clutch is free and operational. The commutators are close to factory specs. 

 

This freaking thing is relatively simple. I am just missing something wiring not connected. 

 

I REALLY appreciate ALL your help.  Please hang in there with me. I owe you all a cold beer!

 

I am beginning to think ir needs an exorcism!

 

I did start it and drove over 30 miles Wednesday. Never made a hiccup one time, the rest of the car is doing well!

1920 Cadillac Phaeton.jpg

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I think that you should remove it from the car and do some bench testing.  Get it so that it "motors" if it does that it will charge.  much easier to play with it off the car to see if both starter and generator functions are working.   Leon

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13 hours ago, garnetkid said:

I think that you should remove it from the car and do some bench testing.  Get it so that it "motors" if it does that it will charge.  much easier to play with it off the car to see if both starter and generator functions are working.   Leon


This would be a good idea, but the s/g is REALLY heavy! Leaning into the engine, reaching down in the valley between the cylinder heads, getting it up and at the same time bringing it forward to clear the cowl, was all that two strong men was able to do. Also the reverse re-install?

 

Yeah, have to remove the hood also. None of these are a super-big job, but a PITA if we could get the wiring correct. It should start very well. There is a wire in the wrong place.

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23 hours ago, DonMicheletti said:

Not that it makes much difference, but the schematic clearly shows a negative ground. I have never heard of a Buick that was not negative ground.

 

Not sure about Buick, but our 1920 Cadillac, 1933 Packard, 1935 Auburn, 1947 Lincoln Continental are  positive ground 6v. Looks like Buick has been neg a long time.

 

Not sure how much this matters. We look for neutral or hot.

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Check the schematic above - negative ground. However either way, it should motor. I dont believe that it has to be polarized since the gen. portion is electrically fed via the ignition switch. It gets its magnetism that way.

 

When I bought my '18 Buick many years ago, the generator part of the S/G didnt work (charge). For years I drove the car as a 'total loss' system where I just charged the battery and hand cranked the engine to start it - very easy. No night driving though.

 

Since your S/G doesnt motor correctly, that means there is something wrong with the generator portion.

I agree, getting that ton of a unit out of the car isnt easy - gravity works well.

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On ‎11‎/‎6‎/‎2016 at 10:56 AM, DonMicheletti said:

Check the schematic above - negative ground. However either way, it should motor. I dont believe that it has to be polarized since the gen. portion is electrically fed via the ignition switch. It gets its magnetism that way.

 

When I bought my '18 Buick many years ago, the generator part of the S/G didnt work (charge). For years I drove the car as a 'total loss' system where I just charged the battery and hand cranked the engine to start it - very easy. No night driving though.

 

Since your S/G doesnt motor correctly, that means there is something wrong with the generator portion.

I agree, getting that ton of a unit out of the car isnt easy - gravity works well.

 

 

Don,

 

He does NOT have a negative ground. This is not a Buick, it's a Cadillac. Here's a cut from the "schematic above", it shows a positive ground.

 

Capture.JPG

Edited by JerryVan (see edit history)
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Bill,

 

The fact that it doesn't motor & also doesn't charge while running, kind of makes sense, since when it motors, it does so using the generator windings and circuits. The starting mode is a whole different circuit. Pretend for a while that the starting mode is a whole different and almost unrelated process. Bottom line is, your generator does not work. Is there the chance that you can get the whole car to where the S/G was rebuilt? You stated, "They tested to be sure the starter and the generator functions were correct and operational". Since they were able to do that in the past, I'm thinking it's something can still do with the S/G in the car with the engine running.

 

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Bill,

 

You say the armature was rewound. Was anything else done or checked? Was the field coil tested for continuity? When you say they tested starter & generator functions, does that mean they actually had the assembled unit on a bench and spun it as a generator and witnessed an output? Or, did they just test the rewound armature, disassembled from the S/G unit?

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On 11/4/2016 at 6:41 PM, garnetkid said:

 

 

On 11/4/2016 at 6:41 PM, garnetkid said:

Bill,  we still haven't heard if the unit is charging when the engine is running???  Did you check that while on your drive.  I ask because I had a similar  problem with my 25-45 several years ago while on a lengthy road trip.  The s/g would not rotate with the ignition  switch on and I had trouble engaging the starter.  It also wasn't charging.  Turned out my armature failed  in the generator portion and I had to located a good one, not easy to find.  You might want to check with who rebuilt the s/g to confirm that the armature was checked with a growler and that all the windings were in good shape.  Leon

 

Mentioned above that the generator does not charge. The ammeter does show a draw when ignition is turned on.

 

At one point, the s/g did motor on when I stepped on the pedal, but no start. But stepping on the pedal SHOULD NOT start it motoring!

 

Bottom line is that the s/g should motor when the ignition switch turned on.

 

The starter/pedal is not in any way connected to the ignition switch.

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Oh, A Cad. Since this is Buick site I jumped to the conclusion that he was talking about a Buick.

Jumping to conclusions isnt a good exercise.

 

However, none the less, the S/G should motor. Not doing so probably means that there is something wrong with the generator portion or the switching. The principle is the same..

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Bill,

 

You state, "At one point, the s/g did motor on when I stepped on the pedal, but no start. But stepping on the pedal SHOULD NOT start it motoring!"

 

NO, when you step on the pedal the starting circuit takes over, this is NOT what's referred to as "motoring", it's now STARTING. Motoring is when current is supplied to a generator and it makes the generator spin, like a motor, NOT like a starter, (when motoring, the generator puts out very little torque, which would never be able to crank an engine, but IS enough the get gears meshed in anticipation of the higher torque to come when the starter circuit takes over). This is why I mentioned above to ignore the starter mode of this device. The starter mode works fine, it's the generator circuit that's bad. Think of it this way, you have both a starter and a generator. They coincidentally exist within the same housing. One is o.k., the other is bad, for whatever reason.

 

(By the way, my caps are not me "yelling" at you. Just trying to be emphatic)

 

 

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1 hour ago, JerryVan said:

Bill,

 

You state, "At one point, the s/g did motor on when I stepped on the pedal, but no start. But stepping on the pedal SHOULD NOT start it motoring!"

 

NO, when you step on the pedal the starting circuit takes over, this is NOT what's referred to as "motoring", it's now STARTING. Motoring is when current is supplied to a generator and it makes the generator spin, like a motor, NOT like a starter, (when motoring, the generator puts out very little torque, which would never be able to crank an engine, but IS enough the get gears meshed in anticipation of the higher torque to come when the starter circuit takes over). This is why I mentioned above to ignore the starter mode of this device. The starter mode works fine, it's the generator circuit that's bad. Think of it this way, you have both a starter and a generator. They coincidentally exist within the same housing. One is o.k., the other is bad, for whatever reason.

 

(By the way, my caps are not me "yelling" at you. Just trying to be emphatic)

 

 

 

 

LET ME BE EMPHATIC BACK! <grin> I understand "MOTORING" 

 

1.) The armature spins. It disengages from the ratcheting clutch. It just hums along on it's own-ster. YUP, it DID when I stepped on the pedal. I do know a hawk from a handsaw. NORMALLY it should only hum on when the ignition switch was turned on by itself. But the pedal DID motor it. CAPS needed? I have rewired this little s/g so many different ways I do not know how I managed this, but I DID! Pedal made it spin. Really.

 

Then rewired it all over again, and no spinning. The only way to engage the starter to work is to put the car in gear, rock it until the engine moves slightly, then stepping on the pedal does engage the engine. 

 

Except for that previous consternation where I know that some-freaking-how know the armature has the ability to spin on it's own when I somehow made it work through some weirdness of rewiring and stepped the pedal. Alternate universe? Carl may think so. Shhhhh.


What should happen, and it ain't, is that the spinning armature should spin when the ignition switch was flipped down. But it won't.

 

Next idea is to pull the hood, pull the s/g with an engine lift and try some bench testing. There is an answer. 

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Bill,

 

Honestly, I hope I haven't upset you. I probably should have used italics instead. As for hawks and handsaws, that's a new one on me. The trouble with these forums is not knowing the person well enough to know what their skill level is.

 

Anyway, after all that, and with your further explanations, I have to agree that removing it is probably your next course of action, miserable as that may be.

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