Repeated jolts to starter with 12V?

[keithb7]

Previous owner found an old non-running car. He puts a couple new 12V battery cables on it. A new 6V battery. Still won’t turn over worth a darn. However a 12V boost does it very well!  Has the car up for sale. So he’s showing it a fair bit. Starting it up fairly often to perspective buyers.  When I arrived to view the car the technique was mastered. 12V with booster cables, right on to the 6V  battery....I cringed. 

 

I Pulled the starter apart today to look around and learn. I found the armature windings badly damaged. Would  multiple 12V boosts cause this damage? I already have another starter  to replace this one. Just curious. I like learning.  Thx. 

Edited June 7, 2019 by keithb7

[Don Coatney]

Others here have had good results Pushing 12 volts through  6 volt starter. I did not. What I discovered was not only does the starter motor spin at twice the speed but the engagement gear also engages at twice the speed into the starter ring gear jamming and locking in to the flywheel ring gear. I went to a 12 volt starter motor and had no more issues.

 

Your solder melt down may have come from extended starter motor run time. I always use short 4-7 second  blasts with a 10-12 second cool down time between.

[kencombs]

I think I've told this tale here before but:  Dad and I had a 54 chevy tow truck in 60-63 in his salvage.  Later 235 but with the original 6v starter, 12v battery.  Never had a problem.

 

What I think could cause an issue is running a starter, 6 or 12 with the starter drive not engaged with the flywheel.  The rpm is just unbelievable.  Centrifugal may be even worse on a 6v since they have heavier windings in the armature.  The one you show seems to have the windings thrown out of the core.  I can't tell if the soldered connections are just torn or melted.

 

A bad starter drive or someone not using the manual engagement type correctly would be my first suspicion.

[keithb7]

In a manual I have seen where they suggest testing the starter by pressung the push button on the starter. Not pushing the foot rod. Therefore not engaging the starter drive clutch. To learn if the starter will spin, without engaging the flywheel. Maybe someone did this too many times? Like mentioned,  it spins awfully fast like this.  The armature windings seem to have been yanked out of their tracks. Then crushed and smeared between the armature and the field windings. The clearance between the two is tight.  Either way, its done. 

[Adam H P15 D30]

Running my 6v starter on 12v for years now without issue, I would say that starter was wasted long before he started jumping it with 12v.

[hkestes41]

I also ran a stock 6V starter with 12V conversion for about 4-5 years with no problems. 

[desoto1939]

12v battery cables should be changed to 6v   00 or 0 gugage battery cables so that you carry enough voltage to the starter.  This is a mistake that most people replace the battery cable with modern cable and when the car is hot then the engine willnot turnover.

 

Rich Hartung

Desoto1939@aol.com

[keithb7]

Thanks folks. Good feedback for a rookie. Yes, It’s quite likely that my starter has been tearing itself apart for some time. 

 

To learn more, I took the windings out too. There were chunks of the copper armature floating around in there. The windings were just starting to see some damage. 

 

If anyone is interested this is what the windings look like inside your starter. They are supposed to be fully wrapped with no coils exposed. The wrap seems to be some type of paper fiber wrap.  The two ends of the coils meet and connect to a brass tab that is directly under the starter switch.  You manually make the connection with your foot, pushing a rod in my 1938 example. 6 volts right off the battery goes thru the switch and directly through these windings seen here. Making a heck of strong magnetic force. 

 

I’m enjoying learning this stuff! It still is amazing to me that they had all this figured out so long ago. 

 

 

Edited June 8, 2019 by keithb7

[keithb7]

My next trick to own a functioning starter from the used one I located. Thanks to a fellow member here, in my area of the world, I have a close match. 

Thanks @dpollo

 

The replacement starter does not have the rear pivot mount for the foot push-rod. The linkage is slightly different but it seems everything can easily be swapped over. 

 

I have a decision to make. Carefully drill and tap mount holes in the replacement starter housing and move the shaft pivot mount over. Or, drop both starters off at the local starter shop and have them swap my housing over. While it’s there test and do any possible repairs on the replacement used starter. 

 

I have access to a milling head with digital controls. I could drill to the exact depth of the starter housing. Staying clear of the windings, still in place. I guess I’d need a bottoming tap to cut threads....Delicate stuff. 

 

 

[maok]

It's not hard to swap the housing bodies over, the most difficult part is removing the field coil screws, the large screws in the housing.

[keithb7]

Thanks Mac. Yes I got two out when I pulled the field coil out. A little propane heat helped along with an impact type screw driver with a large slot bit. That did the trick. 

Edited June 8, 2019 by keithb7

[sser2]

Running 6V starter off 12V battery may be acceptable if engine starts flawlessly. Difficult starts will quickly overheat field coils/armature and cause starter failure. Another concern is excessive arching in starter switch and commutator causing their erosion. 6V starter has parallel connection of windings, which, with little ingenuity, can be modified to series connection for 12V operation.

[DJ194950]

18 hours ago, keithb7 said:

Or, drop both starters off at the local starter shop and have them swap my housing over. While it’s there test and do any possible repairs on the replacement used starter. 

 

 

This is what I would do to get a good dependable starter done up. And get a guaranty!

 

My opinion only.

DJ

[Andydodge]

Also sometimes its good to have someone elses backside that can be kicked rather than trying to land a size 12 on your own backside..............but there are times when its also better to do the job yourself, thats assuming that we know what to do, of course.............lol...........andyd