1951 case SC wiring

[TheNamelessHomestead]

Recently acquired a 1951 Case SC, and as expected, it needs some love. Starts and drives, sometimes does. We have cleaned the fuel lines, carburetor, and sediment bowl. This post however is actually about the wiring. We changed out the gauges thinking perhaps the ammeter was faulty as the tractor currently does start and run, but shows no voltage to battery. After replacing, the new one shows nothing as well. During this work noticed the positive cable is hooked to the ground, and the negative leads to the starter, distributor cap and generator. I know that some older tractors are hooked up for positive ground, but all references say this should be negative ground from the factory. Ok so first question.

Am I in any danger(low,med,high) of damaging items from simply switching the battery around to test it?

Next question
How do I track down/determine if this was altered to be positive ground?

Final question
Is it possible to run hooked up incorrectly and if so would it run good one way and just run better the other?

Thank you in advance!

 

[old]

Recently acquired a 1951 Case SC, and as expected, it needs some love. Starts and drives, sometimes does. We have cleaned the fuel lines, carburetor, and sediment bowl. This post however is actually about the wiring. We changed out the gauges thinking perhaps the ammeter was faulty as the tractor currently does start and run, but shows no voltage to battery. After replacing, the new one shows nothing as well. During this work noticed the positive cable is hooked to the ground, and the negative leads to the starter, distributor cap and generator. I know that some older tractors are hooked up for positive ground, but all references say this should be negative ground from the factory. Ok so first question.

Am I in any danger(low,med,high) of damaging items from simply switching the battery around to test it?

Next question
How do I track down/determine if this was altered to be positive ground?

Final question
Is it possible to run hooked up incorrectly and if so would it run good one way and just run better the other?

Thank you in advance!

I do believe the 1951 Case would have been positive ground when new. As for switching the wires hard to say on some it would cause problems and on others no big problem. As for run be it positive or negative ground the ignition system for the most part doesn't care.
From what you have said sounds like you may have bad connections at the battery or where the cables hook to ground and switch. One can also hot wire it and see if it then runs then go from there to repair the real problems

 

[J Hamilton]

Is your tractor still 6 volt or has it been switched to 12 volt? Originally it would have been 6 volt NEGATIVE ground when it came from the factory. This era of Case tractors built in Racine were negative ground, and the Case tractors built in Rock Island were positive ground. The SC was a Racine built tractor. But, it's anyone's guess what may have been done to the wiring over the years. And yes, "most" 6 volt systems were positive ground, but not always.

 

[casecollectorsc]

I do believe the 1951 Case would have been positive ground when new. As for switching the wires hard to say on some it would cause problems and on others no big problem. As for run be it positive or negative ground the ignition system for the most part doesn't care.
From what you have said sounds like you may have bad connections at the battery or where the cables hook to ground and switch. One can also hot wire it and see if it then runs then go from there to repair the real problems

6 volt negative ground from the factory.

 

[StanIowa]

All Racine built Case tractors were negative ground.. casecollector and J Hamilton are 100 percent correct

 

[TheNamelessHomestead]

Update, after much deliberation I swapped the cables. As hypothesized it fired up and runs fine(fine is a relative term if course). Tested the battery with multimeter. When off the reading came in at 6.5v, while running low idle varied between 6.6 and 6.9. Ammeter still is not showing a reading, possibly hooked up backward? Or bad connection to it?

 

[TheNamelessHomestead]

Is your tractor still 6 volt or has it been switched to 12 volt? Originally it would have been 6 volt NEGATIVE ground when it came from the factory. This era of Case tractors built in Racine were negative ground, and the Case tractors built in Rock Island were positive ground. The SC was a Racine built tractor. But, it's anyone's guess what may have been done to the wiring over the years. And yes, "most" 6 volt systems were positive ground, but not always.

It is still a 6v. I assume the mechanic that installed the battery made the assumption it was supposed to be positive ground, which is not surprising given the “polarity” I have seen on the topic.

 

[old]

Update, after much deliberation I swapped the cables. As hypothesized it fired up and runs fine(fine is a relative term if course). Tested the battery with multimeter. When off the reading came in at 6.5v, while running low idle varied between 6.6 and 6.9. Ammeter still is not showing a reading, possibly hooked up backward? Or bad connection to it?

At an idle the 6.9 shows a slow charge but a charge. At say half throttle you should have around 7-8 volts

 

[TheNamelessHomestead]

Thank you everyone! In the midst of resealing the hydraulic cylinders at the moment so will not be able the test the electrical again til I get that finished, but I will post again when I have it sorted!