My stealth 12V 8N

TheOldHokie

Well-known Member
Location
Myersville, MD
It's official - my 1950 8N is now a stealth 12V conversion. One of the reasons I even bother with an 8N is because I like their classic old school look and an alternator hanging off the side offends my aesthetic senses. So after a lot of debate and research I took my OEM generator in to a local electrical shop on Monday and told them I wanted them to make it look purty, work good, and charge a 12V battery :roll:

I picked it up a couple hours ago and they did all of that and did it well right down to a discreetly stamped 12V just above the Ford logo on the barrel. Now even Bruce won't be able to tell I did the 12V nasty without counting the number of cells in the battery ;-) The essentials for those that care:

8N-10001 - Ford OEM generator
262-14004 - J&N Auto Electric 12V field coils
231-14005 - J&N Auto Electric 12V B-circuit voltage regulator

Bench test results: Charges 14.5 VDC @ 1500 generator RPM, full fields @17 VDC

Now all I need to do is get the tractor back together and give it some field (no pun intended) testing....

TOH

IMG_2139.jpg
 
Looking good!

Of course, you could get one of those new batteries w/o caps & all of us Luddites would never be the wiser. ;)
 
very nice!

I had always said the biggest reason I would not convert to 12 volts is I simply did not like the alternator hanging out there. thought it looks really ugly.

looks like it set you back just over 200? Did that include the Voltage regulator and you supplying the genny for conversion?
 
(quoted from post at 15:54:07 02/20/15) very nice!

I had always said the biggest reason I would not convert to 12 volts is I simply did not like the alternator hanging out there. thought it looks really ugly.

looks like it set you back just over 200? Did that include the Voltage regulator and you supplying the genny for conversion?

The $209 included field coils @ $56.70. regulator @ $59.16, labor @ $78.00, with the rest in small parts and sales tax. I supplied the working 6V generator off my tractor.

TOH
 
(quoted from post at 15:37:24 02/20/15) It's official - my 1950 8N is now a stealth 12V conversion. One of the reasons I even bother with an 8N is because I like their classic old school look and an alternator hanging off the side offends my aesthetic senses. So after a lot of debate and research I took my OEM generator in to a local electrical shop on Monday and told them I wanted them to make it look purty, work good, and charge a 12V battery :roll:

I picked it up a couple hours ago and they did all of that and did it well right down to a discreetly stamped 12V just above the Ford logo on the barrel. Now even Bruce won't be able to tell I did the 12V nasty without counting the number of cells in the battery ;-) The essentials for those that care:

8N-10001 - Ford OEM generator
262-14004 - J&N Auto Electric 12V field coils
231-14005 - J&N Auto Electric 12V B-circuit voltage regulator

Bench test results: Charges 14.5 VDC @ 1500 generator RPM, full fields @17 VDC

Now all I need to do is get the tractor back together and give it some field (no pun intended) testing....

TOH

IMG_2139.jpg
ught to work out real nice. Looks good. 20A?
 
(quoted from post at 16:08:53 02/20/15) Ought to work out real nice. Looks good. 20A?

That info I did not get. I asked but they did not do a max output test. But I will when I get a chance. I imagine it will be a bitlower but hopefully not too low. I am not planning on powering any big motors or Klieg lights with it ;-)

TOH
 
If you don't do lots of night driving, should be fine for bat
recharge.

I have an old JD tractor, and its 6v Genny is single digit amps..
:)
 
Had a '63 Econoline van back in the late 70's. Had a 12v Generator and high output versions were available back then. Could be an option.
 
I like it TOH! Are the 12V regulators any more robust than their
6V counterparts? They always seemed to be the weak link to me
on the 6V tractors.
 
(quoted from post at 20:00:05 02/20/15) I like it TOH! Are the 12V regulators any more robust than their
6V counterparts? They always seemed to be the weak link to me
on the 6V tractors.

That was very much an issue in my planning and I certainly hope so. For what it's worth this one is marked Made in the USA but I think the 6V ones are as well. Got to run to TSC tomorrow and get one of their Exide batteries - seems to be the best price in town by a lot AND I have a gift card. How convenient ;-)

TOH
 
Got one on the shelf that came with a '51 8N I bought a few years ago. Did not charge when I got it so started checking it out. Pulled the end cap and found it wired incorrectly for a 6V 8N and changed the internal wiring and put a known working 6V regulator on it. Worked OK but anytime it sat for a few days I would have to repolarize it. Dawned on me that the genny was indeed a different breed of cat. Took it to an old auto electric shop and gave them the info I had. They put it on a test bench and it put out enough current I think one could weld with it. They then soon concluded it had been converted to 12V. Since it came to me with the 6V reg installed. We re-wired it back as it was and with a 12V reg it checked out fine. I had a NOS 8N rebuild so it was used as the tractor was fine with 6V starting, lites, battery etc. I have in the past used a 101 series Ford Diesel Tractor genny and reg for a 12V 8N conversion which really worked out swell.
 
(quoted from post at 20:13:15 02/20/15)
(quoted from post at 20:00:05 02/20/15) I like it TOH! Are the 12V regulators any more robust than their
6V counterparts? They always seemed to be the weak link to me
on the 6V tractors.

That was very much an issue in my planning and I certainly hope so. For what it's worth this one is marked Made in the USA but I think the 6V ones are as well. Got to run to TSC tomorrow and get one of their Exide batteries - seems to be the best price in town by a lot AND I have a gift card. How convenient ;-)

TOH

Dan I envy that you followed through with what I wanted to do this past summer when my generator died.
I also wanted to convert to 12 V but just can't stand the sight of the alternator hanging off the side of the tractor.
I researched as much as I could to try and locate the proper components to convert over to 12 volts but my rebuild shop has a bunch of youngsters that had no idea about the generator I brought in as a 6 Volt unit let alone converting it for me.

I looked through the Lester catalogs and found the components I thought I needed but was unsure if the Armature had to be replaced also. I see that you did not which means it probably wasn't needed?
I know that Standard Parts makes many different types of voltage regulators both in 6and 12 V A and B circuits. If you get on the standard ignition website and just begin typing in the part numbers beginning with VR it will then list out all the regulators that they have.
I have a few generate is here and I think I will continue following through with the conversion.
 
(quoted from post at 00:47:20 02/21/15)
(quoted from post at 20:13:15 02/20/15)
(quoted from post at 20:00:05 02/20/15) I like it TOH! Are the 12V regulators any more robust than their
6V counterparts? They always seemed to be the weak link to me
on the 6V tractors.

That was very much an issue in my planning and I certainly hope so. For what it's worth this one is marked Made in the USA but I think the 6V ones are as well. Got to run to TSC tomorrow and get one of their Exide batteries - seems to be the best price in town by a lot AND I have a gift card. How convenient ;-)

TOH

<snip>

I looked through the Lester catalogs and found the components I thought I needed but was unsure if the Armature had to be replaced also. I see that you did not which means it probably wasn't needed?

<snip>

Question knowing what your capabilities are why didn't you just convert the generator yourself.

The only reason the armature wasn't replaced is we could not find a 12V version. I likely lost some output capacity as a result which is what Jesse was asking about. If you have a Lester or any other part number for one I would appreciate it.

For $78 I was more than happy to let a professional shop with a shot blast cabinet and the proper tools tackle the crud, rust, and aggravation. I will however re-paint it the "proper" red before it goes back on - wouldn't want the originality police to think I was misbehaving ;-)

TOH
 
I'm eager to hear how this works out for you. My 6V battery is over three years old now and I don't plan on replacing it with another 6V when the time comes. Options are nice and I'd like to keep the original look.
 
Now that's the way to do it! They use to sell 12v generators for the old tractors. There probably are a few of them setting in the alternator/starter shop junk barrels around the world. My mentor Roger, long retired Ford Tractor mechanic has two NOS ones on his shop shelf. I told him to put them in his will to me...

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Dan from what I have been able to come up with you will lose ~ 85% from what you potentially would have had if converted to a 12 v armature. (JMOR ) please correct me if I am wrong. Something about the commutator having less copper strips in its windings.
So about 15amps is still a good output.

Let me find that catalog and will forward on the info.
 
(quoted from post at 10:05:20 02/21/15) Dan from what I have been able to come up with you will lose ~ 85% from what you potentially would have had if converted to a 12 v armature. (JMOR ) please correct me if I am wrong. Something about the commutator having less copper strips in its windings.
So about 15amps is still a good output.

Let me find that catalog and will forward on the info.

Assuming you meant I will LOSE 15% that is the general value I have heard. JMOR and I beat this around before I pulled the trigger. It seems to vary depending on eth actual construction of the individual generator and nobody seems to KNOW what the effect will be on an 8N-10001. That is what we are going to find out ;-)

I also seriously considered using the generator off of a 49-Ford flathead V8. Very similar in appearance and size. I had one all lined up already converted with 12V field and armature:

[u:8fa6cf4905]12V Flathead V8 generator[/u:8fa6cf4905]

But what fun would that have been ;-)

TOH
 
My 12 volt generator, came off a JD 45 combine. Make was "delco-remy" put a wider pulley for 2N. Bought a "Tristar" voltage regulator specifically for DR. I guess I could stamp "FO MO CO" to fool the experts as it looks exactly like a 6V Ford.
Good part "Its still positive ground" which mean all the ignition work like original.
I also went with the 6 volt coil, with the required dropping resistor and ballast. That's 12 volt to coil at start up. 4th cyclinder up (full choke, foot on clutch), at minus temp and its running. Points now 3year old.
Charles Krammin SW MI
 
A noble experiment! I would love to get rid of my nasty
alternator and put back in a nice black generator that would
have the good manners to fit in underneath the hood. The big
question is whether or not it can, without having a 12v armature,
provide enough watts at low revs.

I spent a lot of time some years ago playing around with various
methods to convert old dynamo-equipped British motorcycles to
12V, including rewinding just the fields like you did, and with
electronic converters that did pretty much the same by
regulating the output to 12v while limiting the fields to 6V.

The problem with all such methods that don't include armature
wound for 12v is that, to get 12v out of the 6V armature, you
have to spin it just about twice as fast. This makes the balance
speed for any given load much higher than it would be for the
same machine at 6v. This is usually not a problem on fast reving
machines but is potentially a dealbuster on old tractors which
will spend much time at or near idle.

In the end I gave up and reverted to the original 6v finding that
in real life keeping the cut-in and balance speed low were much
more important than hypothetical output at peak revs. But your
*n generator makes has a lot more watts to spare than the little
Lucas dynamos I was working with, so there is a good chance
you will get away with it as long as you are modest in your
demands.

If you aren't happy with the results, a good auto electric shop,
preferably one which can do rewinding on the premises, should
be able to rewind you a 12v armature.
 
(quoted from post at 00:10:30 02/23/15) A noble experiment! I would love to get rid of my nasty
alternator and put back in a nice black generator that would
have the good manners to fit in underneath the hood. The big
question is whether or not it can, without having a 12v armature,
provide enough watts at low revs.

I spent a lot of time some years ago playing around with various
methods to convert old dynamo-equipped British motorcycles to
12V, including rewinding just the fields like you did, and with
electronic converters that did pretty much the same by
regulating the output to 12v while limiting the fields to 6V.

The problem with all such methods that don't include armature
wound for 12v is that, to get 12v out of the 6V armature, you
have to spin it just about twice as fast. This makes the balance
speed for any given load much higher than it would be for the
same machine at 6v. This is usually not a problem on fast reving
machines but is potentially a dealbuster on old tractors which
will spend much time at or near idle.

In the end I gave up and reverted to the original 6v finding that
in real life keeping the cut-in and balance speed low were much
more important than hypothetical output at peak revs. But your
*n generator makes has a lot more watts to spare than the little
Lucas dynamos I was working with, so there is a good chance
you will get away with it as long as you are modest in your
demands.

If you aren't happy with the results, a good auto electric shop,
preferably one which can do rewinding on the premises, should
be able to rewind you a 12v armature.

Not my area of expertise but maybe JMOR will chime in and help us out (hint).

I think your 2X RPM number neglects the change attributable to the increase in the number of field coil windings. I already know this generator produces ~14 VDC @ 1500 armature RPM. The belt drive is about 1.5:1 step-up so that is about 1000 engine RPM. It will charge a 12V battery at that engine speed - so the real question is how fast ;-)

I spent a lot of time reading about "dynamos" and 12V conversions including old British motorcycles and cars before I decided to go the route I did. Based on what I read there and other places I expect to see a rated current output loss of roughly 15%-20% - e.g. my 20A generator is now a 16A-17A generator.

To put that in perspective the Lucas C40 dynamo on my 1960 TR4 is rated 22A @ 2000-2500 armature RPM and a load of .61 ohms. It powers my rather electrically spartan TR4 just fine even while idling in rush hour traffic with all the lights and wipers on and the Smiths heater motor on HIGH .

Using that as a baseline I figure that a 17A generator is enough to power a few lights and the ignition on my tractor. I don't anticipate needing anything other than those electrical accessories and I also don't expect to spend a lot of time stuck at idle in rush hour traffic ;-)

But I do thank you for the armature rewinding idea. If the analysis above proves faulty there is an old school electric motor shop that could rewind it just a few doors up from the place that rebuilt the generator. Or I could just put one of my spare Lucas C40's on the tractor. Wouldn't that be a bit of bother for the N-series correctness police :twisted:

TOH
 
Converting (or designing) a generator like this is always a matter of tradeoffs. If you go with 12V fields and 6V armature your cut-in/balance speed doubles, but so does the number of watts you can safely take off it at speed. If you rewind the armature for 12 then you lower the balance to back where it should be, but limit safe output to the same number of watts as it the generator could safely produce at 6v in its original form. So it makes good sense to try the cheaper option first.

Oh, for those who would prefer to DIY it, the the tricky part is doing generator work is getting the pole pieces that hold the coils back in place (better always to not disturb them if at all possible). They must fit absolutely flat and in place as they are made to fit very close fit to the armature if they are to be effective, and must be fitted perfectly in the body when they are tightened, which usually requires some sort of press to hold them snug against the outer body. Old english manuals suggest a "tapered round wedge turned from oak to be driven in", but I have found one of those import bargain tool store tail pipe expanders, the kind that expands as you turn the nut, does the job very nicely for about $6.



Not my area of expertise but maybe JMOR will chime in and help us out (hint).

I think your 2X RPM number neglects the change attributable to the increase in the number of field coil windings. I already know this generator produces ~14 VDC @ 1500 armature RPM. The belt drive is about 1.5:1 step-up so that is about 1000 engine RPM. It will charge a 12V battery at that engine speed - so the real question is how fast ;-)

I spent a lot of time reading about "dynamos" and 12V conversions including old British motorcycles and cars before I decided to go the route I did. Based on what I read there and other places I expect to see a rated current output loss of roughly 15%-20% - e.g. my 20A generator is now a 16A-17A generator.

To put that in perspective the Lucas C40 dynamo on my 1960 TR4 is rated 22A @ 2000-2500 armature RPM and a load of .61 ohms. It powers my rather electrically spartan TR4 just fine even while idling in rush hour traffic with all the lights and wipers on and the Smiths heater motor on HIGH .

Using that as a baseline I figure that a 17A generator is enough to power a few lights and the ignition on my tractor. I don't anticipate needing anything other than those electrical accessories and I also don't expect to spend a lot of time stuck at idle in rush hour traffic ;-)

But I do thank you for the armature rewinding idea. If the analysis above proves faulty there is an old school electric motor shop that could rewind it just a few doors up from the place that rebuilt the generator. Or I could just put one of my spare Lucas C40's on the tractor. Wouldn't that be a bit of bother for the N-series correctness police :twisted:

TOH
 
Thats a good looking setup. 20 amps is pretty much the maximum you want to put out on a totally enclosed generator like that. If it puts out more than that for long periods of time, things get kinda warm. If you need to rewind the armature theres a place in Chicago called Major Armature that did custom rewinds. I haven't been a rebuilder for 15 years but they did good work back then. Good luck with the setup! Mike
 
Hey TOH, I bet that's going to look good,I've been thinking of doing the same sorta deal using my old generator of my 1969 Harley Davidson.i use a 3 wire solid state voltage regulator and would need to figure how to mount, try looking up this company,it may help(?) Cycle Electric
 

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