1934 50 series starter?

[Frank Wilkie]

I pulled my starter on my 1934 50 series. It would crank good and start but after driving and warming up, on a restart it will sometimes slowly crank over like it was dragging. I would again crank it and then it started right up.. We have taken it apart but nothing is showing up.. So we are doing a cleaning and everything looks good..  I question the numbers on the starter.. There is no tag on the starter body but on the starter switch mounted on top there is a Delco tag..  #1513 15 725..   I couldn't find the 50 series starter motor serial number in the Master Parts Book listed..  Would the 40 series be used on my 1934 50 series motor?

[Robert Engle]

What size battery cables are you using?  I always suggest going to heavier cables as you will get more amperage to the starter. 

 

Bob Engle 

[32buick67]

54 minutes ago, Robert Engle said:

What size battery cables are you using?  I always suggest going to heavier cables as you will get more amperage to the starter. 

 

Bob Engle 

Frank,

 

I agree with Bob and I highly recommend installing a larger 2/0 wire gauge minimum on 6v systems if you haven't already done so.

I recently rewired my car, and I now use 3/0 wire gauge for the ground and positive wires.

I also meticulously cleaned all contact points for the ground and positive connections, and it made a big improvement to starting.

 

My battery is about 6.3v open circuit when not in use, and during cranking it only drops to about 5.9x volts.

When I start my 32 Buick 272cuin engine, it rapidly rotates and fires almost instantly whether cold or warm, even with an original mechanical fuel pump.

 

I have original gray cast iron pistons which weigh over 26oz each, which albeit original, but extremely massive, and my rotational mass is far higher than most folks today who use modern aluminum pistons.

Even with the greater mass, my starter rotates very quickly, primarily due to the oversized 3/0 wire gauge.

I am an electrical guy by nature, and I have done much testing and research for 6v cars, and I have found that 2/0 wire gauge is the minimum size for a reliable ground and starter conductor size.

 

Auto-electricians manual shows 170-185 amps at 4.1 volts for a 1934-50 series starter, ref attached pic.

 

While its possible your issue isn't related to wire gauge, amps, etc.....put voltmeter on the starter terminal while cranking the engine to see if the voltage is too low.

 

With DC motors (starters), the voltage is directly proportional to rpm, so if you have low/sluggish rpm on a starter motor, then the issue is 99.44% of the time related to low voltage.

Increasing starter motor voltage can be accomplished by increasing battery voltage (bad idea), or decreasing wire resistance by using a very large wire gauge (lowest cost and best initial idea).

 

0.56% of the time the issue can be due to starter internal issues which are more complex and require additional troubleshooting.

Most of the time the starter will go as far as to try to melt itself by trying to please the operator by applying torque when the correct 6.x battery terminal voltage is applied during a starting sequence.

Avoid this mode.

As you already know, don't overcrank a starter, let it rest and cool between cranking: 200amps X 6volts = 1200watts..........cranking for 10 seconds is 12kw-sec which is a lot of heat to dissipate in the copper and iron.

 

Hope this helps,

Mario

 

[Frank Wilkie]

10 hours ago, Robert Engle said:

What size battery cables are you using?  I always suggest going to heavier cables as you will get more amperage to the starter. 

 

Bob Engle 

I've got 3 /0 wire ground .. in fact I have two grounds.  One to frame and other to starter bolt. 

[Frank Wilkie]

I still would like to know the correct Delco ID number for the starting motor itself. 

[32buick67]

Take a look at the Delco numbers in the screenshot I posted to see if they are any help, and I might be able to get more info late tonight about the starter if you need, as well as 40 vs 50 series parts.

I have another Delco electrical book with part numbers of individual distributors and generators, but I have to see if it includes starters.

 

What is the terminal voltage on the starter when sitting idle cold and when cranking?

[Frank Wilkie]

7 hours ago, 32buick67 said:

Take a look at the Delco numbers in the screenshot I posted to see if they are any help, and I might be able to get more info late tonight about the starter if you need, as well as 40 vs 50 series parts.

I have another Delco electrical book with part numbers of individual distributors and generators, but I have to see if it includes starters.

 

What is the terminal voltage on the starter when sitting idle cold and when cranking?

Ok,   I've found the Delco number for the starting motor #727 G model / 12897..  The Solenoid # 1513  15725 ..  Now I'm needing a wiring schematic for the solenoid.. The guy working on it made a quick note of the wiring but now now sure.. we activated the solenoid and it kicked in the starter on the bench but wiring it up to the car he's not sure.. He's getting a short out from one of the two 3/8 copper studs on the solenoid due to a steel bushing that sleeved over one of studs. It has insinuator washers but the steel sleeve makes contact with the metal bracket..  There again a good diagram of this area would be very helpful..   sorry it's a lot to ask... 

[32buick67]

Frank,

I am going to post what I can find now in segments as I do the research...hopefully there is something helpful for you.

Post the starter terminal voltage when you get a chance so we can see where things are at with regards to what the starter motor is seeing.

 

[32buick67]

[32buick67]

Turns out we have the same starter armature unit on our cars, #823881

[32buick67]

[32buick67]

 

[32buick67]

[32buick67]

[32buick67]

[32buick67]

[32buick67]

1934 series 40 info as a reference:

 

[32buick67]

34-40, 734-Z

 

[32buick67]

[32buick67]

That's all I can find tonight Frank with my tired eyes, been a long work week...

Hope this helps...

 

Mario

[Frank Wilkie]

Thank you very much for your time and consideration....   the mechanic that took the starter apart is good but old school (shade tree).  He didn't make a sketch of how it came apart on the solenoid and now he's getting a ground on one of the copper studs.  I was looking for another solenoid working or not to take apart and see what's missing or exactly how it goes back together..  

[Grimy]

See the FIBER bushings mentioned in the parts lists--and even a fiber stud. 

[Frank Wilkie]

ok, we spent 4 hrs back on the starter today..  no luck.. so I'm done..  Looking to buy a used solenoid or maybe a new old stock one.  I would also consider buying a complete starter with solenoid.  just call me 618-889-6855....  Delco starter # 727G..   Solenoid # 1513

[32buick67]

Frank,

This diagram of a 1933 is similar to 1934, maybe there are some clues to help with the troubleshooting:

[Rock10]

Solenoids are pretty simple. Used to build them at Delco in the 70's.

Just a big switch between the battery and starter.

Big electromagnet that moves a plunger to make the electrical contact and engage the pinon in the flywheel.

Sometimes the contact (a big washer) gets brunt or corroded.

According to the diagram above one big terminal goes to the battery. The other big terminal is fastened to the starter coils. The small terminal energizes the magnet to make the contact.

Is this how yours looks?

[Bloo]

On 4/29/2022 at 4:54 PM, Frank Wilkie said:

He's getting a short out from one of the two 3/8 copper studs on the solenoid due to a steel bushing that sleeved over one of studs. It has insinuator washers but the steel sleeve makes contact with the metal bracket..  There again a good diagram of this area would be very helpful..

 

Neither copper bolt can make contact with the steel frame. Can you please clarify if your Buick has Autostart or not, as solenoids for both kinds have been posted in this thread. Electrically there is no difference in the solenoid itself, but the Autostart one has a relay on the back, making the "normal" solenoid terminal inaccessible, and that causes confusion.

 

The copper bolts cannot contact the steel frame in any way, and if there was a steel sleeve, then there must have also been shouldered fiber washers, or at least a shouldered fiber washer on one side, or a fiber sleeve over the steel one, to prevent contact to the steel frame.

 

You should read continuity to ground though with it all assembled. The diagram below is one I posted in a 1936-37 thread, and it shows why. There are 2 windings in a solenoid, a pull-in coil and a hold-in coil. You can see them more clearly in this diagram. Both begin at the relay terminal in the picture (or at the solenoid terminal on a car with no Autostart). One coil ends at ground, the other ends at a copper bolt, specifically the copper bolt that will be connected to the starter windings when the solenoid is installed.

 

 

As you can see, there is a path from one of the copper bolts, through the pull-in winding to the relay contact, and from there through the hold-in coil to ground. I would have checked them separately. Whatever way you check them both windings must be good, and there will be a continuity path from one of those copper bolts to ground. There can not, however, be a short from a copper bolt to the steel frame.

 

Things to pay attention to on a 30s Buick solenoid:

 

1. The copper bolts. This is the most common problem by far. Bolt head erosion causes the copper disc to no longer reach the bolt heads. You can sometimes turn a worn bolt around backwards to get a new piece of bolt head. More often than not, someone already did that and used up the other side. Then you need new bolts. Don't neglect this. "Rebuild Kits" show up on Ebay now and then if you cant get the bolts anywhere else. The 1970s GM copper bolts might even be adapted, but as I recall they are an extremely poor fit, probably requiring a bunch of ingenuity. The bolt head must stick up to the original height.

 

2) The plunger adjustment. It has to be checked with the boot off if there's a boot. There are threads at the plunger, marked "adj. stud linkage" on the diagram above. The gap is measured as shown at the far left. 1/8" is correct for some later Buicks, but would need to be checked with the manual in your case. To check, you need to hold the solenoid plunger all the way in. This means ONLY the outer part of the plunger, not the center threaded part sticking out, and not any part of the linkage.

 

3) The windings, as already mentioned above, need to have continuity. There should be continuity through the hold-in coil from the relay contact to the solenoid case (ground). There should be continuity from the relay contact to the copper bolt that will connect to the starter windings. Both windings must be good, and if not, you need a different solenoid. I have seen an open hold-in coil on a 37 Buick 80 series. Among other problems, It cranked extremely slow because the copper disc just buzzed on the copper bolts, never making good contact.

 

Good luck, and let us know how it turns out.

 

Edited May 2, 2022 by Bloo (see edit history)

[Frank Wilkie]

We are up and running today..    but I still would like to purchase a second spare starter and or solenoid.. I just like back up..

[EmTee]

Glad to hear -- so, what was the breakthrough...?

[Frank Wilkie]

the mechanic said he took it all apart again and reassembled. checked for any grounding to the frame (none found). Put in car. He called me and said he couldn't get it started.. It was flooding. So I went over and sat in the car , pushed the clutch in , hit the starter button, and started up right away.  Go figure!..   I suspect that he pumped the gas feed and it flooded.. We let it run a while to heat up and dissipate the gas on the outside of the carburetor.  Shut it off and then hit the starter again and it started right up...   As you may suspect the foot gas pedal start was eliminated  before I had the car..  A dash button was installed..   Keep me in mind if you run across another starter/solenoid. I like having back ups..   I've been asked several times if this car was for sale since I have been looking for a starter..   The answer was ," I don't have it up for sale but if someone wanted it more than I do it would take a hefty offer".  I have owned many old Buicks in the past and enjoyed driving them..    

[Frank Wilkie]

I just drove it home..  Arm out the window and a big smile... 

[EmTee]

I'll say it again; that's a beautiful coupe! 

[Frank Wilkie]

Update on starting problem.:   Now it's starting good but the mechanic forgot which terminal to connect the wire coming from the generator over to the starter.   Could anyone help me with this ..  I don't want to guess..  

 

[60FlatTop]

On 4/28/2022 at 7:26 PM, Frank Wilkie said:

It would crank good and start but after driving and warming up, on a restart it will sometimes slowly crank over like it was dragging.

While you are working on it check the action of the ignition advance plate the points are mounted on. It should snap right back quickly if you turn it and release. Some have a cork lubrication pad that they ride on and it dries out over the years. If it is sticky it will creep back over time. If you do a quick warm restart it may still be giving you too much advance and give that dragging feeling. A couple drops of oil in the lube pipe may not do the job.

[EmTee]

If like my '38, the mechanical advance weights are located out-of-sight below the breaker plate.  When I removed the breaker plate I discovered the entire mechanical advance assembly covered with surface rust.  I disassembled everything, cleaned off the pieces and lubricated it for reassembly.  If the weights are frozen in a partially advanced state that could cause a hot start issue.

[Bloo]

4 hours ago, Frank Wilkie said:

Update on starting problem.:   Now it's starting good but the mechanic forgot which terminal to connect the wire coming from the generator over to the starter.   Could anyone help me with this ..  I don't want to guess..  

 

 

Is there a little relay hanging off the back of your solenoid (behind the copper bolts) with 2 little terminals on it?

 

If so, the 2 small screw terminals are the relay coil. It floats, so it does not matter which terminal is which. You mentioned your car has been converted to a starter button, so that makes it harder to guess what to do.

 

On a Buick with Autostart, one of the 2 little wires goes to the autostart stuff to provide 6v to start, and the other goes to the charging system somehow to provide a ground, but only when the car is not running. To make the car crank, one of the little terminals must be grounded, and the other must have 6 volts.

 

Be sure the relay cover has not been clobbered, and is not shorting to either terminal. It comes close. If you don't have the little relay, ignore all of this post.

 

[Frank Wilkie]

on one of the (2 small screw terminals) I have one wire coming from the installed starter button under the dash. This wire relays the power to kick the starter in.. There is no other wire attached to the other (terminal).  So I guess I'll connect the wire coming from the generator to thas terminal..  We noticed that the coil under the cover had a burned out end to it with no connection.. so there was no purpose now since the original equipment of gas pedal starting was taken out.