6 to 12 volt with no parts

A friend well known for making most anything work with almost no money spent, casually mentioned that several years ago he had changed his N to 12 volts. Captured my attention since we had been talking about generators. With a few pointed questions his comment was " The generator does not know what voltage it is producing." "I did put the voltmeter on the regulator and adjusted the cutout voltage and the other relay until I thought it was about right."

After thinking about the changes I do not see any technical reason that the change to 12 volts this way would not work just fine. Maybe guessing at the regulator adjustments isn't the best idea.

Anyone else converted to 12 volts this way? Seems like in the worst case one would only need to buy a 12 volt regulator.

Thanks.

Bill Stanley(NC)

When making such a mod via the voltage regulator it is important to change the generator pulley so the generator turns faster otherwise there won't be charging at reasonable engine speeds.

Readjusting the voltage regulator is probably asking for trouble in the long run because the power dissipated in the shunt coils will quadruple. There will be a resistance rise but no where near enough to compensate for the voltage change. Voltage regulator lifetime under this abuse will depend on how conservative the original design. You don't really want the coils to heat enough to change resistance because that will change the voltage calibration.

I've run a 6 volt generator at 24 volts just fine by turning it faster even with 24 volts on the field.

The field core will saturate probably not far above 6 volts so that increasing the field voltage beyond that will have almost no effect on the generator output voltage. It would reduce field heat and voltage regulator point wear to connect a fixed resistor in series with the field coils, value equal that of the 6 volt field coils. That is simpler than rewinding, though rewinding would cut the field current in half and further preserve the voltage regulator.

The simple modification without parts will probably need a new voltage regulator sooner than later. Then it would be good to use a 12 volt regulator as the replacement.

Brushes are not a problem, similar brushes are operated at 120 volts with about the same number of commutator bars.

However, I have a fundamental problem with conversion to 12 volts. I figure that with care the machinery ran 40 or 50 years with 6 volts, why change it now? The main problem comes from replacing battery cables and buying the economy size made for Toyota cars, not the heavy duty ones REQUIRED for 6 volts. Those fat battery cables (no smaller than #2, preferably #1 gauge), and maintenance of the connections and starter made my 8N crank just fine, even outside in the middle of Iowa winters. Its important to realize that old starters are often worn, and respond well to new bearings, brushes, and bendix drives. I KNOW that helped my 8N immensely. Applying 12 volts to a worn starter just guarantees it will be destroyed sooner.

Gerald J.

I had 1950 8N and in the early 70's the engine was pretty tired. It plowed and disked gardens in the spring and the rear blade moved lots of snow in the winter.

On six volts in the warm weather it cranked and fired up just fine. In cold weather it was endless jumpering, starter overhauls, etc.

As is said in another post, 12 volts is a solution waiting for people to admit to a problem... I remember the confusion when people swapped Ford car starters in the latter fifties. Bolt a '54 or '55 six volt starter on the later 12 volt system and the thing was running before you could let go of the key! Put a later 12 volt starter on a 6 volt system and they went up in smoke fast.

Back to my 8N... Somewhere around '71 or '72 I installed a used 60's era Delcotron and mechanical regulator and 12 volt battery. Yes, I replaced with 12 volt bulbs and installed a '58 Ford type ignition ballast resistor.

When I hit that starter button, no matter how cold it was, the thing was running before I could get off the button. The at least annually rebuilt and Bendix replacement routine ended.

A year or so after that I re-built the engine, using thin sleeves and high dome pistons from an NOS flathead hop up kit. Only difference was that I needed premium fuel for heavy pulling tasks. I also replaced a chewed up flywheel ring gear removed a pile of broken starter bendix parts from the flywheel housing.

Other than approximately a 3 year battery replacement schedule, a quickie alternator brush replacement one day, and a fan belt someplace in the approximately 15 years, the whole system ran without problems for me 'till I sold it in the mid 80's. Far as I know it's still whirring along someplace in Southern Iowa.

My point is that them 6 volt starters are wound with heavy windings and generally built "heavy duty". Twelve volts allowed the designers to down size the wiring and generally lighten up the mechanicals. Stay with them 6 volt starters and power 'em with 12 volts!

Do so and you've turned the starter equivalent of a wimpy monkey trying to crank start an engine into an 800# gorilla that sends a message to start immediately or have your flywheel ripped off!

Yes, bad ingition and/or fuel problems will still inhibit cold starting.

But, with 12 volts the thing is running in an eye blink and the total stress on the system is proportantely lower than the seconds, and sometimes minutes, of high stress grinding away on a 6 volt system.

We all know "what". The technical matters have been worked out for many years. It's up to each person to decide "when". If you're a purist, then paint it pretty and run it in nice weather.

On the other hand, if you want an all weather, never fail you type 8N, quit screwing around abusing a fine N series machine and get with the 12 volt program!

p.s.- The same trick has worked just wonderfully since ??? (way before I got it) on my '57 Farmall 450... IHank

By the way I am not suggesting others follow my friends route from 6 to 12 volts but simply reporting an case that I found interesting. Many would get in trouble. But many also butcher an alternator conversion. I didn't inquire about the changes made to the ignition.

My friend is in his 70's, straight as an arrow and previously a service technician and supervisor for Borroughs. He make the conversion several years ago and has been using the tractor without problems.

I also wondered about the field current but doubt if the difference between 7 ohm (12 volt system) and whatever it would be for 6 volts makes much difference. Conceptually from a power standpoint the total energy to service the battery is about the same in either case. In other words the generator heat shouldn't be much different but the regulator might cycle more often.

Shunt windings, don't know. Your comment caused me to think about the shunt again in a different light. From it's appearance I'm betting its resistance goes up with temperature. Thanks for your earlier help and comments on a charging problem.

Bill Stanley(NC)