8N - 12 Volt

[Alan Davis]

I recently purchased a 1952 8N. It had been converted to 12 volt.

Can someone please tell me:

How I know if I have a 1 wire alternator?
How to tell if I have a 12 volt coil?
Best way to tell if the alternator is charging when Ammeter does not work.

Thanks,
Alan

 

[Putter]

-A 1 wire alternator has the voltage regulator inside the unit so no bundle of wires running to a regulator.
-Is there no identifying marks like a mfg data plate on your coil?
-You will need a volt meter. Measure battery voltage before you start and after it is running. Should rise from around 12V to about 13.5V running.

 

[Jerry/MT]

I recently purchased a 1952 8N. It had been converted to 12 volt.

Can someone please tell me:

How I know if I have a 1 wire alternator?
How to tell if I have a 12 volt coil?
Best way to tell if the alternator is charging when Ammeter does not work.

Thanks,
Alan

Why do you think they call it a "one wire alternator"?

For a side mount distributor on the 8N, if you have a VOM , set it to the lowest resisitance scale. A true twelve volt coil will have ~ 3.2 ohm primary coil resisitance and a true 6 volt coil will have ~1.6 ohms resisitance.( You meaasure it across the coil terminal connections.) If the electrical system mod was done correctly and a 6V coil was used, you'll find a resistor in series with the coil. Finally, some coils ar emarked "12V" or "12V with resistor required".
If you have a front mount distributor, I can't tell you what the coil resistance should be because I understand they vary all over the place and asIi understand it, they run with a resisitor in series at 6V. Try Yesterday's tractors Ford N forums.

If you have a voltmeter and the engine is running you should see a consistan 13+ V at the battery terminals. if you don't have a volt meter just wait a few days of operating and the battery will run down. Ammeters for these tractors are cheap so i's advise you to replace you non-functional one. make sure that it's hooked up correctly before you change it out. if your tractor was modified by some one else, it just may not be connected correctly. Again See Yesterdays tractors forum for wiring diagrams etc.

 

[barbqranch]

When measuring resistance with an ohm meter, it is always a good idea to short the leads together first and make sure it is reading 0 or close to that. It isn't unusual for the plugs on the leads to make a poor connection and you have to twist them around to bring down the resistance.

 

[Soundguy]

ditto what jerry said.

also.. follow the wire from/to the coil, look for a resistor inline.

if you want / need a side mount 12v coil.. a napa IC14SB is a 16$ replacement.

a 6v coil on a front mount will likely read between .8 and 1.25 ohm.. and a 12v coil can read anywhere from 1.3 to 2.5, .. they are all over the place. the new 12 square coils need to be run in series with the oem dash resistor for 12v just like the oem square 6v coils need the dash resistor for 6v.. etc.

ont he alt.. if a gm/delco 10/12 SI model.. there is a plug with 2 spade lugs marked 1 and 2.. usually these are capped on a 1 wire model, thent he charge stud on the back.

the volt meter on the idea is a good one. 12.6 before start and 13.2-14.7 afterwards. note.. some 1 wire units need to be run up to mid high rpm to excitebefore they start charging.. but will then charge down to as low as 600 rpm or so..

soundguy

 

[Alan Davis]

Why do you think they call it a "one wire alternator"?

I knew I would get this.

I thought maybe I had a 1-wire after looking at some on line diagrams, however besides the 1 terminal marked Battery on the alternator there are of course 2 more wires inside a plastic clip plugged into the alternator. These wires have been cut off at about 3 inches.

Thanks everyone for this helpful information!

Here's what happened to start my questions about the alternator.
First of all the tractor had been starting good. I hooked up a 5' finish mower for the first time using the PTO since my purchase and after installing a new PTO shaft (change to 1-3/8) and Over Running Coupling.
When I started through some taller grass and put a load on the 8N it started acting like it was running out of gas and finally stopped. While trying to re-start the battery was drained. I seemed to me to be fuel related so I drained the gas out of the carb and tank. It had lots of trash, rust. I then pulled the carb, took it apart and cleaned it out. It had trash it it also. I then installed a new Fuel Valve and Sediment Bulb assembly. With the battery dead I had to jump start it. Started to try to use the finish mower again and the same thing happened again. Took the carb off again cleaned it out again and reinstalled. Jump started adjusted carb and it purred like a kitten and ran better than ever.

During all this fuel issue my battery ran down and just seemed to not receiving a charge. Got me wondering about the alternator and coil and the 6 volt to 12 volt conversion that a previous owner had done. There was a resistor mounted on the tractor but was not hooked up. I took the coil off and found it marked 12 volt but it had printed on it something like "To be used with an external resistor". That kinda threw me but I did not hook up the resistor.
I took off every connection in the charging system cleaned, filed and shined them up. Jump started again ran up and down the road for a few minutes, turned the tractor off and it re-started with out a jump and the battery sounded very strong. i feel somewhere in the line there was bad connections keeping the battery from charging. Anyway as of late yesterday my 8N is starting and running great!

This morning I am going to start on hooking up the lights. All bulbs
are still 6 volt and are not wired up. Anyone know what volt bulbs I need to get?

Long post but maybe my experience will help someone else.

Thanks again!
Alan

 

[Soundguy]

well.. if it's 12v.. you need to get a 12v bulb. TSC and napa have 12v bulbs to fit most popular lamp shells. take an old one with you as a reference. I don't have the sylv / ge aprt number with me.

use a vom to see if the alternator is exciting and charging.. bat should be 12.6v before start and 13.2-14.7 after running.

if there were wires cut to the plug it likely was a 3 wire alt wired as 1.. many work that way but you can get more reliable excitation by hooking back up as 3.. if it is truly a 1 wire regulator in there, hooking up as 3 wire will NOT damage it.

spade #2 jump to charge stud.. spade #1 run thru a 194 marker lamp ( insulated casing of course ), to the same wire that feeds the resistor / coil coming off the key switch.

key on, lamp should lite up.. once running over 400-600 rpm, lamp should go out indicating charge. standard 'idiot lamp' concept.

soundguy

 

[rrrkkk]

After the bulbs you need to put a solid state in the distributor. I did my NAA several years ago it made a new tractor out of it. It will idle at 300 yes 300RPM and will start in any weather after sitting for weeks.

 

[Soundguy]

?need? he may WANT to.. but for sure doesn't 'NEED' to.

besides.. with a good carb tuning it can idle at 450rpm.. alternator rpm usually needs to be around 400-450 to even turn on , and then only if a 3 wire... so being bale to idle at 300 rpm isn't very usefull.. you aren't generating electricity, oil pump volume is diminished.. which can be something to think about on an old machine.. especially an N that don't start with much OP anyway, plus hyd pump volume and / or pto hp will be negligible at 300 rpm.. so again... pretty useless to idle at 300 rpm... unless you just want to brag that your machine can idle at 300 rpm.. ??

soundguy

 

[rrrkkk]

?need? he may WANT to.. but for sure doesn't 'NEED' to.

besides.. with a good carb tuning it can idle at 450rpm.. alternator rpm usually needs to be around 400-450 to even turn on , and then only if a 3 wire... so being bale to idle at 300 rpm isn't very usefull.. you aren't generating electricity, oil pump volume is diminished.. which can be something to think about on an old machine.. especially an N that don't start with much OP anyway, plus hyd pump volume and / or pto hp will be negligible at 300 rpm.. so again... pretty useless to idle at 300 rpm... unless you just want to brag that your machine can idle at 300 rpm.. ??

soundguy

Yes i said need the 300 rpm idle isn't the reason to change, you must like hard starting and changing points and condenser I don't. I can see you must be an expert as you have over 29,000 posts.