Thinking about 6V to 12V conversion

   #1  

flusher

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I'm getting around to the point in the restoration effort on my 1951 Minneapolis Moline BF tractor

http://www.tractorbynet.com/forums/...eapolis-moline-bf-restoration-continuing.html

where I need to get serious about the electrical system. Been wondering if I should convert from 6V generator-style to 12V alternator type. It's an easy conversion.

However, my concern is with the starter-- it's a 6 volt Delco Remy 1109609. I understand that you can run a 6V starter on 12V provided you limit the time you crank the thing. The concern is with the Bendix operating at 12V. From what I read, the Bendix will move faster at 12V than at 6V and might slap the ring gear on the flywheel hard enough to damage it.

Am I worried about nothing? Or is it a potential problem?
 
   #2  

Soundguy

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yes it's a potential problem, and yes.. many do it.

there are alotta 12v fords out there with 6v starters, solenoids and oem bendix.. ya pays yer money and takes yer chances. If it busts.. get a new one.. it might have busted anyway.

soundguy
 
   #3  

Travelover

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Not sure if it is practical here, but back in the day when they put 12V Corvair engines into 6V Bugs, they used two 6 volt batteries in series, with a center tap between them, so you could run some circuits (the starter in your case) at 6V and other circuits (lights, etc) at 12 volts.

The trick is to have room for two batteries.
 
   #4  

Retired Iron Peddler

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I have my father's 1950 Avery R converted to a MM BF. I have used it to mow about 5 acres for about 15 years. I use a 12-volt battery and have converted the coil to 12-volts. I haven't changed the generator to 12-volts. The old 6-volt generator is still in place and I disconnected the 6-volt cut-out. After using the tractor, I re-charge the battery with a battery charger. So far I haven't had any problems continuing to use the 6-volt solenoid on the starter or the 6-volt starter. I don't stay on the starter very long when cranking the tractor.

Bill
 
  
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flusher

flusher

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Not sure if it is practical here, but back in the day when they put 12V Corvair engines into 6V Bugs, they used two 6 volt batteries in series, with a center tap between them, so you could run some circuits (the starter in your case) at 6V and other circuits (lights, etc) at 12 volts.

The trick is to have room for two batteries.

Thanks for the heads up.
Cool idea. Space for two batteries is no problem on the BF. I should be able to mount them in-line end-to-end. Just have to weld up a new battery tray.

DSCF0029 (Small).JPG

DSCF0069 (Small).JPG
 
  
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flusher

flusher

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I have my father's 1950 Avery R converted to a MM BF. I have used it to mow about 5 acres for about 15 years. I use a 12-volt battery and have converted the coil to 12-volts. I haven't changed the generator to 12-volts. The old 6-volt generator is still in place and I disconnected the 6-volt cut-out. After using the tractor, I re-charge the battery with a battery charger. So far I haven't had any problems continuing to use the 6-volt solenoid on the starter or the 6-volt starter. I don't stay on the starter very long when cranking the tractor.

Bill

That's encouraging news. Thanks for the input.
 
   #7  

Soundguy

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Thanks for the heads up.
Cool idea. Space for two batteries is no problem on the BF. I should be able to mount them in-line end-to-end. Just have to weld up a new battery tray.

View attachment 140751

View attachment 140752

you can get commercial 12v start/6v run kits as well.. and I remember you used to be able to get 12v batteries with a center electrodes for 6v taps.. not sure if they still make them..

soundguy
 
   #8  

Soundguy

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forgot to mention.. you can usually get a 6v gen reworked as 12v as well... then just need a new regulator and lamps.. etc. and battery.

soudnguy
 
   #9  

Retired Iron Peddler

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forgot to mention.. you can usually get a 6v gen reworked as 12v as well... then just need a new regulator and lamps.. etc. and battery.

soudnguy

Yep, that's what I plan to do on my Avery R/MM-BF. It's always cranked very slowly on 6-volts. My father had the starter overhauled, but finally installed an 8-volt battery and used them on the tractor for years before they became impossible to find. After he passed away and I got the tractor, I started using the 12-volt battery to start the tractor.

The only thing I haven't figured out is how to work the cut out and the resistor on the light switch that controls the generator charge rate. I'll probalby install a voltage regulator in place of the cut out and disconnect the resistor. Some of the MM-BFs and the later model MM-BG had a voltage regulator mounted on the 12-volt generator since there isn't much room under the hood at the cut out location next to the ignition coil. I want to keep everything looking original as much as possible.

Bill
 

Soundguy

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If you rebuild the gen as 12v vs 6v.. the I would for sure go with a regulator.. as the resistor/tickle setup with the lamp switch won't be calibrated to provide the correct field curent for the new gen.. ( would likely make it overcharge.. )

soundguy
 
 
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