1951 WD voltage question

I recently bought an Allis Chalmers WD and the guy I bought it from thought it was a 12v system. I bought a new 12v battery for it and fired it up. It runs great but after several times using it the battery went dead. I tried checking amp draw, voltage at battery while running etc...and it appears the Generator may need to be polarized cause it is discharging possibly. My question is with no amp meter, no marks on the voltage regulator how do I determine if the Generator is truly 12 volts? The starter and Distributor have the Delco-Remy tags on them but nothing stamped in the middle. The only marking on the Generator is a 12V stamped on the top near the pulley end. Your thoughts?

Bob, it is + ground sir. I'll take a look, any thoughts on determining the generator voltage?

Now another question, how do I convert to - ground?

Thanks for the help sir!

To flash the Generator what do I need to do?

Gerald you've been awesome. Thanks so much

Mike56073 wrote:    Are you sure it's a 12V generator?  It would be odd to have that on a WD, most of the time they were converted over to Alternators if they went to 12V.

 No he's not sure, that is why he asked: My question is with no amp meter, no marks on the voltage regulator how do I determine if the Generator is truly 12 volts?

Many so called 6 volt generators have operated for years on a 12 volt system.

Mike56073 wrote:    Well, if he doesn't know what he has, then why are you having him check everything with a 12 volt battery installed?  Sorry, but in my line of work the smart(er) thing to do is make sure you have the correct components installed before you even make the connections.................

 He already bought the 12 volt battery and was asking what to do to make it work and check it out. If the generator is original it won't hurt a thing to hook it all up and run it. And like I said many original 6 volt generators have run for years working fine on a 12 volt system.
 If he doesn't hook it up and check it out, he will never know if the third brush has been bumped up to put out higher voltage or if the pulley was changed to make it run a little faster. If it works he's good to go. If it doesn't charge the battery, he has many options. He can leave it the way it is and charge the battery on a charger a couple times a year. He can tweak the system to get it to charge enough to work OK, he can have the generator rebuilt as a 12 volt or he can switch to an alternator. He still is out nothing to hook it up and try it the way it is. How smart is that?


Edited by CTuckerNWIL - 30 Apr 2012 at 6:45pm

   Sorry, my bad. I missed the part where he said he had 12V stamped on the genny.

Again the guy I bought this from told me it was a 12 Volt system but I don't think he knew Jack Sh#t about it. So I am trying to educate myself.

Edited by Geppy - 30 Apr 2012 at 7:52pm

Geppy wrote:

That looks like one of the external resistors used on a 12 volt system with a "6 volt" coil.

Looks like it is a 12V gen from the step down in the field frame.

I'm getting in on this late but, if the Gennie says 12V stamped into it, its probably a 12V unit. Also, a lot of your 12V versions have the step down chassis as Coke mentioned. A good thing to do is loose that resistor, and install a 3.0 ohm internal resisted coil. This will eliminate missing, hard starting etc that comes with those external ballast resistors. You need to establish 2.7-3.3 ohms of resistance in the Ignition circuit running 12V's with a 4 cylinder engine. The 3.0 ohm unit sticks you right dead center. What I would do is have a local rebuilder check the operation and output of the Generator. Determine whether or not the Gennie is working properly and its total amperage output is. Once that is established, have your rebuilder mate a new VR to the Generator via max output recorded. Now you have the two units that will work together as a team. Make sure your wiring and connections are good, and wire either PG or NG. After you decide which way you want to run the system, polarize the system. You should be good to go from there!  HTH
Steve@B&B

If you have problems finding a coil, we have lots of em' in stock...
Steve@B&B

No. The difference in coil resistance takes care of that.