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What all is involved in a 6 to 12 volt conversion on a machine with a magneto? starter? gauges, for sure.

See Gazer's thread on this forum, on his OC46 12 volt conversion.
But it is possible to internally convert a 6volt generator to a 12volt generator - then you know it will fit
I am having my Oliver 70 converted now. But its a lot cheaper to get a 12 volt alternator like Gazer's set-up.
Yes to new gauges, but the starter and magneto, in my experience, will be fine. Some say the 6volt starter will have a shortened life from going twice as fast, but since a well-tuned system starts very quickly, this is a moot point. And some say the magneto can spin so fast that it does not 'click', as the weights inside are set for 6volt turnover ( I am sure there's a better way of saying that!). I have never had that problem yet.
Otherwise, I say 12 volt is the way to go. I get really cheesed-off trying to start a 6 volt OC3 loader with all that cold fluid drag of engine and hydraulics in the Winter months (it gets to below zero regularly up here [with exception of last year])....I just jump it from my car which can be dangerous, so don't take that as a recommendation.
Or most most of my machines I just have a 12 volt battery and disconnect the generator.

Sorry, that Hotratz's thread:

Easy Alternator Conversion
viewtopic.php?t=2227 (http://www.cletrac.org/newbb/viewtopic.php?t=2227)

According to this, these replacement gauges can be used with 12v or 6v. Its what I have on my 70
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWAX:IT (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360196189577&ssPageName=STRK:MEWAX:IT)

regarding the magneto issue about turning over too fast.......that is what the inpulse coupling does in a magneto, it makes it snap fast to produce a hot spark. if mag is turning fast enough to override impulse coupler than it is turning fast enough to make a hot spark. the issue regarding a 6 volt starter being spun on 12 shortening it's life....i am no expert but it seems like i heard that when you double the votage the amperage is cut in half , sooo, if a 6 volt starter is designed to handle the increased amperage of the low voltage 6 volt system, running it on twice (12)the volts would be twice as easy on the starter. military vehicles use 24 volts to reduce the amperage even more wich results in less starting problems due to bad or corroded connections etc. I don't think the starter spins fast enough to hurt it's self on 12 volts. we had a conversion on a wc allis that has had the same 6 v starter in it for 20 years and is still going strong.

A little clarification on motors and dual voltage:

If a motor is only wound for 6 volts and you apply 12 volts the amperage and RPM will be higher. If you have a dual voltage motor in which you can change the winding configuration by re-arranging the hook-up with the external winding leads you will control the RPM and current at the higher voltage to it's design spec. Unfortunately this dual voltage option is more common with AC motors than DC starter motors so you can expect higher RPM and current with 12 volts.
I've run many 6 volt starters on 12 volts in more than a couple types of vehicles with no problems.

I have an OC-3 that was converted from 6 to 12 volt. The hardest parts was making the bracket for the alternator. When I first got the machine the magnetto had never worked right and it was rigged with a coil. I later took a distributor off of a Farmall H and hooked it up with the 12 volt system. The machine runs great and starts great. The starter has been rebuilt but the 12volts do not seem to bother it and the engine fires right up since it has been rebuilt and tuned in nicely. You can see it in the picture before we put everything back together. We did however end up moving the coil since the wires were not fitting very well right there.

I've converted 3 6 volt units to 12 v (2 OC-3's and a continental F140), with no starter problems after 20 odd years.

I put 37 amp delco alternators on, and they didn't seem to bother the 30 amp ammeters. The alts were converted by a shop to a self-energizing single wire configuration. Doing it again, I'd use a smaller imported alt on the 3, because the Delco sticks out a fair bit. I had to get wider pulleys (stock at alternator shop) to take the wide OC-3 fan belt.

The only other change on the 3's was light bulbs - I shifted all to 12 v, and put sealed beams on the fronts. The 4" (?) ones clamped right in with the ring on the original holders.

It dramatically improved starting, especially in sub-zero temps.

6V starters on 12V are a non-issue.  Between our old tractors,  and friends with old tractors and cars,  I'll bet I've seen a dozen that had 6V starters on 12V with no issues.

Generally:

On rigs with a starter solenoid, you should change to a 12V solenoid.   Starter is fine as is

Ignition:   If coil,   you'll need a 12V coil, and if needed,  a matching resistor.    Because resistor equipped 12V coils are designed to have the resistor bypassed on start--for a hot spark on start--you'll need to device a bypass, depending on the car/ truck/ tractor



Electric gauges:   Ammeters don't care,  so long as the terminals are reversed if the ground is changed  (6v pos ground to 12V neg ground, example)  Some ammeters are very tolerant of high charge rates, as when going to an alternator.   S/W  30A  units routinely put up with 60A  !!!pegged!!!   alternators.

Other electric gauges should NOT be run "on a resistor."   These simple "volt drop" resistors sold in car parts joints are designed for a specific load  (Ohm's Law)   or for  "non critical junk like wiper and heater motors.    electric gauges should use a "regulated"  source.   One made for the job is called a "Runtz", Google it.   Another way is to use the instrument panel regulators used on Ford and Chrysler in the 60's -70's.      Some gauges  do not care as to polarity, some do.

Lights:  Obvious.  Change 'em

Generators:   It has been reported that some 6V generators will work as is--with a 12V regulator, on 12V,  and in some cases you can change the fields.     If you swap to a 12V generator,  it can be off most anything.  You can polarize a generator for either ground.  The thing that can be damaged on a generator system with polarity is the regulator.   Some generator regulators  (OEM)   had contact alloy  that would be damaged with reversed ground  (arcing.)    Many OEM  regulators were designed for EITHER ground polarity to reduce inventory.   You should run 12V systems ONLY at negative ground in my opinion,  simply because that is the current accepted norm.   Use a regulator that "matches the generator."   This is very important,  not only to get the correct field circuit,  but most generator systems have a "three relay"  regulator,  one of which is the "current limiter"  which   protects the generator from charging too much current.

 I'm an alternator fan,  myself.   The age old standard is the internal -regulated- Delco, used since the mid '70's.   If you must,   you can get  a "one wire"  regulator---the component that determines this.   I prefer  the old "three wire"  units.    On our old A/C  M,   there was a pulley on the mag drive, which  because of it's location,  necessitated mounting the alternator facing aft,  and so it rotated CCW.    While you can obtain  "backwards"   cooling fans for Delco alternators,  ours worked OK  this way for years.

Roadrunner. Why do you prefer the 3 wire alternator units??
I am sick of 6volts, so I am going to convert a bunch of OC3s and maybe my OC4 soon...I will use a small unit like Hotratz's OC46 conversion.
Anyone want to buy some 6volt batteries  

Well don't forget you can use two 6V battieries on 12V!

So far as the "one wire"  "three wire"  deal,  REALLY    it's  "two wire"/  "three wire"  so it's ONLY  one more wire.  Maybe it's me, maybe problems from the past, I don't know.  Some of the "one wire" units have/ used to have certain  excitation issues, you had to wind up the engine to get them to charge, specially if they've been sitting.  If you didn't happen to notice this,  you could run the tractor 1/2 a day and run the battery low.

"Three wire"  are only one more wire  than  "one wire"  which are really  "two wire."     On the Delcos,  you jumper no2 to the battery connection   so that's the second wire.   The no1 connection goes through an indicator  (idiot lamp)  in series to switched 12V,  or through  a rectifier diode  for  isolation.

I realize that on a "mag"  engine this can be problematic, but there are several ways around the problem.   The biggest, of course, is on a "rig"  with a mag and a key ignition,  instead of the "key"  controlling 12V on/off, it controlls a ground to the mag.  One easy solution is to use an oil pressure switch to run the field excitation.

Do the two 6volt batteries need to be identical, or can they be of different sizes/specs, so long as they are 6v.
I could easily do this on my OC4 since it has two boxes/armrests.
Not so easy to fit 2 batteries on my OC3-31! I already have one strapped on the drawbar shelf. The other one would have to be on my head

Quote from: "oliverchris"Do the two 6volt batteries need to be identical, or can they be of different sizes/specs, so long as they are 6v.
I could easily do this on my OC4 since it has two boxes/armrests.

As long as the batteries are in good condition,  I don't see why they need to be identical,  "up to a point."    Let's say you had a  bizzare situation,  something like a small garden tractor  with a very small  "motorcycle class"  battery,  in series  with a very large (group 2)  6V.    In that case,  the smallest battery  would not be designed for the charge rate  that the large battery  was.  


I would think  that some difference in size would be OK  so long as the cells are in good shape

You're setting yourself up for problems unless both batteries are close to the same size and age. Simplify matters with one 12 volt battery.

I would tend to agree with Hotratz about simplification with a 12 volt battery, but I would not throw away two perfectly good 6volts to go out & buy a 12 volt. I would charge both 6 volts to full charge, check the voltage on each cell. Let them set for several days, in cold weather if possible. Then check them again. If you have a battery tester that loads the battery, I would then load test them & check volts again. If all the cells hold to within 3/4 of a volt of all the others I'd use them till they wouldn't hold a charge, then i would buy a 12 volt. But that's just me.
  Scott R.