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What type shim for starter armature?


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Ive got a 1937 buick with a delco-remy starter. Ive been having trouble and i noticed the armature has a lot of longitudinal endplay and the brushes arent centered over the commutator. I need some shim washer... What type of material is best? Copper? Stainless steel?

Thanks

James C

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Yes. It is a lot. I actually put an 1/8" nylon shim and that took up most of the play. But otherwise this is a fairly low mileage car. The bushings at each end are nearly perfect with no radial play at all. By the way, the shim didnt help my slow start/stalled starter condition. If I test for voltage drop from the stater post on the solenoid to ground on the starter case i get 3.0volt drop. But this is with the starter stalled since it will not turn the motor over anymore. I get acceptable voltage drop thru pos and neg batt cables. And i even welded nuts to the frame to create multiple ground points. Can the magnets go bad or get weak?

It is a delco remy 734z20171002_202520.thumb.jpg.6dd5f0bcb49a47bea55a3e0c512f5d1d.jpg

 

Thanks

James C

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OOPS no text.

The original spacer on my '38 Buick coupe seems to be phenolic and it is hard.

The starter coils can be bad if the insulation is shot from cranking too long. However most of the time the cables are not for 6 volt cars - these engines draw a lot of current.  I ran my ground strap directly to the starter mount bolt.

How is the strap between the solenoid and starter body terminal?

In the photo, you commutator looks good. Did you turn and undercut it?

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There are no permanent magnets. The magnetic field is made by the current flowing through the field coils. If the coils short internally, the magnetism will be weak.

 

You get 3 volts from the starter solenoid terminal to ground? That is not drop, that is the voltage the starter has to operate. Drop would be what is lost in the cables. What is the voltage drop across each cable when the starter is locked up?

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I doubt endplay is a big deal. The armature will go where the magnetic and mechanical forces pull it. Tightening it up wont change this, and might even make it drag a little more. I don't have the manual handy. What does Buick say about endplay?

 

DonMicheletti's photo in post #7 shows what the correct commutator-end thrust washer looks like, It is some kind of phenolic or maybe even leather. I think it acts as a brake when the starter disengages.

 

I enlarged the picture in post #6 and it looks like your armature is undercut. This means that the insulation between the copper segments on the commutator is cut lower than the copper so that only the copper touches the brushes. This is the right thing to do to most electric motors, but not starters. You would have to look in the manual to see if Buick undercut it, but even if they did, it probably shouldn't be undercut now. If you have some brushes with a lot of copper in them, like the ones shown in DonMicheletti's post #7, the copper will just fill up the grooves and short out the armature. The starter will draw loads of current and barely turn. If yours is like this, clean the copper out of the grooves and it will probably start working again.

 

If that isn't it,  have a good look at the copper bolts that form the terminals on the back of the solenoid. Look where the copper disc contacts them. How burned up are they? In normal operation, the solenoid bottoms out, knocking a pin that moves the copper disc. The pin is spring loaded, so the disc and bolts can wear/burn quite a bit and still work. When it gets bad enough, the disc wont quite touch the bolt anymore. It will sort of bounce and spark, never quite connecting good enough to work properly. The starter will turn slow, if it turns at all.

 

If the solenoid, when pulled all the way in, can push that disc all the way to the copper bolts, and compress the spring on the pin even a tiny bit, then the copper bolts are not the problem.

 

If it isn't that either, the solenoid might have a burned out coil. There are two coils in one of these solenoids, a pull in coil and a hold in coil. I once saw a solenoid that had one of the two coils burned out. The solenoid would pull in, and the copper disc would bounce on the copper bolts just like the bolts were burned up and shot, but they were not. The starter ran super slow. This was on a 37 Buick.

 

There is a diagram in the shop manual, either the main wiring diagram, or maybe in the starter section, that shows you the wiring inside the solenoid if you look close. With everything disconnected from the solenoid I was able to check both coils with an ohmmeter. One was open.

 

Lastly, there is an adjustment for how far the solenoid pushes the starter drive out. If this is wrong, the gear could drag on the starter housing, or maybe the copper washers and bolts might not get fully engaged. There is a specification in the manual. I believe you hold the solenoid plunger all the way in mechanically (or electrically by engaging it on the bench with the starter motor disconnected from the solenoid). Do not hold the linkage in, only the large part of the plunger. Measure from the tip of the starter drive gear to the flat to the flat spot inside the starter nose by the bushing. The manual has the spec. It might have been 1/8 inch. To adjust, disconnect the linkage to the fork. The center part of the plunger is threaded, and you can adjust it in or out while the linkage is unhooked.

 

Battery cables need to be pretty large on a 6v car. 00 gauge is perfect. 2 gauge will work. The ones from the parts store might work, but probably wont. Also, both the frame and the block need to be grounded. If your negative cable goes to the frame (I'm guessing it does), there needs to be a big heavy strap (or another battery cable) from the frame to the block or transmission. Make sure it's there and connections are clean.

 

Let us know what you find out.

 

 

Edited by Bloo (see edit history)
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Thanks everyone. Ive been through the starter once and cleaned everything and i must have lost that phenolic spacer. I dont remember seeing it, but there is definitely evidence this starter has been opened up before. Anyone got any sources for said spacer? I will hopefully have some time to work on more diagnosis tonight.

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There are lots of sources for phenolic sheet material.

You could try shops that rebuild generators and starter motors.

There are many on-line companies that sell phenolic washers that may have a size/thickness that works, such as this one. http://plasticwashers.newprocess.com/product/custom-washers/phenolic-washers

And companies that will custom make a washer. 

You can buy phenolic sheet material  on-line and make a washer on a lathe, or drill press.

 

Paul

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So i found the problem (probably). The terminal to the field coils had become un-soldered. So with much frustration i got them soldered back. But unfortunately now the starter doesnt spin at all. Perhaps the coils got too hot and shorted? I dont think the coils are grounded to frame, but they do give a reading in the kilo-ohms from field terminal to ground. The resistance thru the field coils is 0. Is that too low? Field shorted? Pretty frustrated at this point

 

EDIT: the coils actually have both .02ohm resistance!

Edited by 70sWagoneers (see edit history)
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0 (zero) ohms means no resistance. As in a really good connection between the two measured points.

 

An open is high resistance, also known as infinite resistance. As in no connection between the two measured points.

 

The starter sitting on the ground will not spin when the solenoid is engaged, but draws a lot of current?

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I edited my last post about the field coils having no resistance. They both actually have .02ohms. And they are not grounded to frame. They are fine.

 

So in the course of tearing apart, testing, and rebuilding this starter probably 10 times... the starter now works!! It works perfect! except the solenoid doesn't work...

 

My two main problems were the field coil terminal unsoldered and shorting to the frame and then the jumper cables I was using to bench test with over the last few days wasn't carrying enough juice to spin the starter. I removed the field terminal and fabricated insulation out of nylon sleeves, nylon washers, and a rubber washer and then resoldered the field coils. That was the cause of my slow start all along! The bunk jumper cables would deliver a big spark and fire the half of the solenoid that works, but literally wouldn't budge the starter at all. So I thought the starter was bad for the last two days. On a hunch I tried a different pair of cables and the starter spun fine. Lesson learned.

 

But now the solenoid wont fire. Before I put it back in the car, on the bench, the solenoid fired and worked correctly. I put the starter in the car, pressed the start button and everything worked perfectly. I let it fast idle and warm up while I picked up some tools. Shut her down, hit the started button again.... and nothing. Ran a jumper wire from POS battery source to the S-terminal; got a big spark but no movement. The starter turns over fine still.

 

So, anyone have any guesses on how to open up the solenoid can to get at the pull in and hold in coil???

 

Thanks everyone, I've learned a lot here.

James C.

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Some you can take and some you can't.

On those you can you will most likely find the copper contacts have arced to the point they can't make a good connection and need filing.

I prefer to fix what I can because my success with "new" rebuilt stuff has been less than stellar....... :angry:

 

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I doubt you can repair the coils inside the solenoid. If they are bad, you will need to find another solenoid.

 

I don't remember which terminal is the "s" terminal. you are going to have to show me.

 

Here's how to test the coils in the solenoid: Disconnect the strap from the solenoid to the starter motor. Disconnect the little relay on top from the solenoid coil as well.

 

Note from the graphic that the pull in coil and the hold in coil are connected together at the end that normally connects to the little relay. At the other end, the hold in coil is connected to ground, but the pull in coil is connected to the copper bolt that normally connects to the starter motor.

 

Test resistance from the terminal that normally connects to the little relay to a bare spot on the solenoid case (ground). There should be very little resistance, a few ohms at the most.

 

Now test resistance from the same terminal (that normally connects to the little relay) , but this time to the copper bolt that would normally connect to the strap to the starter motor. There should be very little resistance here also, only a few ohms.

 

If both of these test good the solenoid coils are ok.

 

Speaking of the little relay, is it clicking down when you try to start the car?

 

You say the solenoid "wont fire", does that mean the solenoid is pulling in but not turning on the starter motor, or is it just not pulling in at all?

 

 

IMG_20171005_010851.jpg

Edited by Bloo (see edit history)
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It isnt labeled as the "s" terminal but i was searching for common terminalogy. The s-terminal small lead on the positive side of the solenoid relay that gets power from start button or switch.

 

For a while, before this rebuild, when you hit the start button (yes ive got a start button) the small relay on the solenoid would click but the plunger wouldnt move. As of now, nothing happens in the solenoid or its relay when I put power to s-terminal. Nothing but a big spark so power is going thru it so im guessing its grounded somehow. I will hopefully have time tonight to work on it.

Thanks

James C

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Bloo, what is to the right of the starter in your picture?  I would like to know what the two wires off the top relay connect to.

 

On a later GM solenoid (12 volt style) the S terminal is what the start function of the ignition switch connects to (gives 12 + volts to). The R terminal is the resistor connection. I know, we are talking 6 volt system here, so there is no need for an R terminal or resistor in the ignition coil lead.  So I am guessing the  two wires off the relay connect to the carburetor starting switch circuit, with neither acting just like the S terminal in a later GM solenoid as originally wired.

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Yes, if it is sparking, it might be shorted somehow.

 

Here is how it is supposed to work: 6v comes from the autostart stuff (carb switch and vacuum switch) to the little relay. the current flows through the coil on the little relay, out the terminal on the other side, and to ground through a terminal in the original 5-terminal voltage regulator.

 

I bring this up because to pull in, the little relay needs not only 6v on the "s" terminal, but also a ground on another terminal. If the car still has an original 5-terminal voltage regulator, a dirty ground contact in the regulator would could cause the relay not to pull down.

 

Since the relay needs both terminals ("s" and ground) connected to pull down, It is possible for the starter button to be in the ground side instead of the positive side.

 

When the little relay pulls in, the points close, connecting a copper bolt (the one with the battery cable on it) to the pull in coil and the hold in coil. The pull in coil "finds" its ground through the starter windings. The hold in coil is permanently grounded. Both pull. This pulls the solenoid plunger in, engaging the starter drive.

 

When the plunger pulls in, it knocks the little pin in the back, pushing the copper disc back, and shorting the two copper bolts together. This does 2 things, it turns the starter motor on, cranking the engine, and it shorts out the pull in coil by connecting both ends of it together. The hold in coil continues to work.

 

The car continues to crank until either 6v ("s") or ground is removed from the little relay.

 

 

 

 

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30 minutes ago, Frank DuVal said:

Bloo, what is to the right of the starter in your picture?  I would like to know what the two wires off the top relay connect to.

 

On a later GM solenoid (12 volt style) the S terminal is what the start function of the ignition switch connects to (gives 12 + volts to). The R terminal is the resistor connection. I know, we are talking 6 volt system here, so there is no need for an R terminal or resistor in the ignition coil lead.  So I am guessing the  two wires off the relay connect to the carburetor starting switch circuit, with neither acting just like the S terminal in a later GM solenoid as originally wired.

 

Yes, That is exactly it.

 

On a newer style GM solenoid, you only need to send battery voltage to one terminal. I had forgotten that it is labeled "S". That terminal goes directly to the solenoid windings, and there is no small relay.

 

An equivalent to the "I" terminal does not exist here.

 

On this system they have added a small relay to kick the solenoid windings. and both ends of the coil have terminals. To get one of them to behave like an "S" terminal, you have to ground the other one.

 

Buick's original autostart (vacuum switch and carb switch and so on) sent battery voltage to one side of the small relay coil. The other side of the small relay coil connected to the "ground" terminal on the 5 terminal voltage regulator. The "ground" terminal is actually a set of points in the regulator that grounds only when the car is not running. It prevents the starter from engaging if the car is already running.

Edited by Bloo (see edit history)
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Thanks for the explanation Bloo, I've been staring at these electrics for days, but I get so lost in all the ways things can ground out that I get lost sometimes!

 

But alas, once again it was something fairly simple... Got home. Hit start.... Nothing. Engaged plunger manually... Started! Shut her down. Hit start... Nothing. Jumpered from POS batt to s-terminal... Nothing. Took box cover off solenoid relay, engaged small relay contacts manually... Started up again! Put cover back on, went and hit start button.... Nothing! This is when dad comes out and wonders what wrong. I jokingly say "it seems like it works when i take the cover off and doesnt work with the cover on". He says "maybe the cover is shorting it out". Eureka! And this is from my dad who has no idea about anything automotive! He even admitted he didnt know what he was saying, but whatever, he was right! The small relay cover was pressing into the s-terminal and grounding it out. So in the end, ive got an all original, rebuilt and cleaned starter, a cache of new unused starter rebuild parts, redundant heavy duty ground system, and a thorough understanding of my starter. So next is the generator which intermittently charges!

Thanks everyone.

James C20171005_193928.thumb.jpg.3065fe2430e3eecf3df1cd52e220b3bc.jpg

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