Ford Hundred Series 12V Conversion (very long)

Well since I do have a life other than the computer it took me longer than I thought to get it together. But it is finally done so here it is.

Hope this helps you under stand how this is done and makes for a easier conversion.

So you have decided to convert your Ford hundred series tractor to 12v for whatever the reason. Their are many ways of converting but this is a step by step guide of how I would do it using a Delco 10SI alternator. This guide is set up for the 601/801 with a dash light but I will try to adapt it to the 600/800 model also for those that need that setup. I will also try to add some testing procedures so you can check your system if you should ever have any problems.

Lets all get on the same page by me starting with the fact that this is not for everyone. Whether or not you leave your tractor 6v or convert to 12v is a personal decision. Whether you use a new 12v regulator with your old 6v generator or use these steps is also a personal decision. Converting from 6v to 12v can be the best thing you ever did for your tractor or your worst nightmare depending on how you do it. All parts are available at part stores or over the internet and just bolt on. While it cost more some may want to buy a ready to install kit to do this conversion. These kits save a lot of leg work trying to find all the correct parts. I have seen these kits available from many places but I must warn you some of these kits are put together the cheapest way. I have even seen some that will cause problems down the road just because they do not have the correct parts to do it properly. At the very least I think you should read through these pages so you can get a idea on how this system works. It should give you the info you need to help you decide what path is best for you and tell you how to install it correctly. If you are interested in a conversion kit this site (YTMAG) sells a kit. You can see it Here

While I have never bought one of these kits it may be right for you. The question I would ask is if the alternator is a 3 wire set up or a true 1 wire setup. You can not tell them apart by looking at them. The only difference is the internal regulator. If it is not a true 1 wire; is some form of diode included in the wiring harness to prevent feed back through the #1 or F wire to the coil. Another thing to look at is does it come with a 12v to 6v resistor or a 12v coil and does the coil need a resistor.
The 3 wire alternator was used in cars and I think it is best for a tractor. You can get a 3 wire alternator from any parts store. My AutoZone store has them for $23.99. The true 1 wire alternators were originally used on marine engines. They are more expensive. J.C. Whitney has the marine alternator for $129.99 plus $16.99 in shipping. They also have a 3 wire car alternator that has had the regulator replaced with the 1 wire regulator. It goes for $79.99 plus $13.99 in shipping. That is $93.98 I do not feel this alternator is worth $69.99 more than the AutoZone alternator but that is your choice.
The thing you need to watch for is some will sell you a 3 wire alternator and tell you to wire it with only 2 wires leaving the 3rd wire that hooks to the #1 or field terminal on the alternator off. This will work but requires you to rev the cold engine all the way up to get the alternator to start charging. Not a good idea in my mind.

If you are trying to crunch the numbers to see if you want to do this or whether you want to buy a kit or get the parts at a local parts house lets go over what you need. Remember all these parts will not be in the kit and some will have to be bought locally.

Delco 10SI alternator
5/8” alternator belt pulley
Delco wire adapter for spade plugs on the alternator
Alternator bracket
A 12V to 6V coil resistor OR a 12V coil
Miscellaneous wire and wire ends
12V battery
Dash charging indicator light or one way diode
A simple $20.00 volt/ohm meter from Wal-Mart is also good to have for testing.

That is all you will need to get the tractor running but you will eventually need to replace all your light bulbs and gauges that use electricity such as the fuel and amp or volt gauge.

So now lets look at every part in the system 1 by 1 and see what you need new and what can stay.

Testing; You can test your battery to see if it is charged with a volt meter. Use the meter and do not guess at it by looking at how bright the lights are. To truly test the battery though you will need to take it to a shop or parts store and have a load test done on it. Remember with your new 12V system it will be negative ground and positive to the starter relay.

Testing; The 4 post relay used on the 601/801 works like this. The battery gets hooked to one of the large studs and the starter to the other. The small I terminal gets hooked to the terminal block so it has power only with the key on. The power goes through windings in the relay and out the small S terminal which gets hooked to the starter button on the transmission. You should have power at both small terminals and the starter button with the key on. When you push the start button it grounds this power causing the windings in the relay to magnetize and move a plunger that connects the two large terminals sending power to the starter.
The 3 post relay on the 600/800 works the same way except it does not have the small I terminal. It gets its power internally from the big battery terminal and not from the key. If you do not have power at the small terminal with the battery hooked up your relay is bad OR you have the battery hooked to the wrong big terminal. The bad part about this relay is it has power to crank the motor all the time. All you need to do is push down on the starter button where as the 4 post relay can only crank with the key on. This is probably one of the main reasons Ford changed to the 4 post relay in the 601/801. They offered diesel motors and if it were to crank it could start as you do not need any power for a coil.

Testing;
You can remove the starter and use a set of jumper cables to test it. One cable goes to the starter case and the other to the starter post. It should run like this. For a better test take it to a shop or parts store and have a draw test done on it. This shows how many amps it takes to run the starter.

Testing;
The battery terminal on the back of the alternator gets hook to the large battery post on the starter relay. So it has power all the time. This is the wire that charges the battery.
The #2 or S (stator) spade was originally hooked to power in the wiring harness to compensate for voltage drop in the wiring. With a tractors small wiring you can just connect it to the battery post on the back of the alternator via a short jumper wire. This wire tells the alternator when the charge is enough and shuts the regulator down as not to over charge the battery.
The #1 or F (field) spade gets hooked to the terminal block with power only with the key on. It energizes the alternator on start up so it will start charging. This wire is the dreaded night mare of the conversion so lets look at it in detail.
A lot of people do not understand how it works so they try all kinds of stuff to correct problems it can create. In fact many just leave this wire off and only hook up the above two wires. It will work like this; but as I said before you need to rev the cold motor all the way up to get the regulator to leak enough energy to start the alternator to charging. Some have even tried to put a smaller pulley on the alternator so it will spin faster at lower rpm’s. The 1 wire alternator uses a different regulator so it will leak enough energy at a lower rpm and only uses the wire that connects to the battery terminal; but like I also said I do not feel it is worth $70.00 just so you can leave these two wires off.
The problem lies in the fact that this #2 wire gets hooked to the terminal block in the same spot as the coil. Once the alternator starts to charge it will back feed power back through this wire. When you turn the key off to kill the motor it will not shut down since the coil is being fed from this power. So we need to find some way to send power to the alternator through this wire on start up but break the back feed of power to the ignition system. So how can we do this?
Well since you only need to supply the power to the alternator for a few seconds to get it to start charging I have seen some people that put a toggle switch or a starter/horn button in this wire. You would start the tractor and hit the button for a few seconds to start the alternator to charging then let it go. The alternator will continue to work as long as the tractor is running and when you shut it off the button is the break in the wire you need to shut down the motor. Problem is you need to remember to push the button every time you start the tractor. NOT LIKELY….
So we could go to Radio Shack and get a POWER diode. This allows power to go one way but not the other and works automatically. No buttons or switches to remember about. Ask for part # 1N4003. I think these diodes sell for about $1.00. While part # 1N4001 is a smaller one I have heard that people have been using this one also with no problems. The diode must be hooked up the correct way. The cathode end goes toward the alternator. This end is usually marked in some way such as a white band. You can test it by hooking it up and turning on the key with the motor off. If you have power on both sides it is hooked up correctly. If not turn it around.
But wait the 601/801 has a dash warning light and that is the way GM set this system up to work in the first place. See if we put a small 2 wire 12V light bulb in this wire it will work like it was originally set up to work. Power goes from the terminal block to the light and then out the second wire to the alternator. This makes the light come on but leaves enough power to energize the alternator so it will start charging. Once the alternator starts to charge it back feeds power to the light. Since the power is the same on both sides of the light it goes out and lets us know the alternator is charging. When we turn off the key this light bulb comes back on because it has power coming from the alternator but not the key. This happens so fast you may not even see it but it is enough to stop the back feed of power to the ignition system allowing the coil to stop firing and in turn shutting down the motor. If you do not have a 601/801 and do not want to drill a hole in your dash for the warning light but would like one that is possible also. All you need is a small trailer clearance light that does not ground through the case but grounds through a second wire. You can mount this any where under the dash. You may not be able to see it from the seat but it does its job of preventing back feed and if you suspect it is not charging a quick look at the light will tell you.

Like I stated before you need some kind of diode or light in the #1 wire to prevent back feed of power to the coil. This way uses a car ignition key available at Auto Zone for about $14.

On the back of the key switch you will see 4 post.

Battery; This is where the power wire coming from your terminal block will be hooked. (battery side)

Start; leave this plug empty because it is not used in our application

Run; This is where the wire the other wire bringing power back to the terminal block will be hooked.

Acc; This is where we are going to hook the #1 or F wire coming from the alternator. Do not run the #1 wire to the terminal block as the wiring diagram shows but hook it to this Acc. post instead. Remember in this set up you do NOT need any type of diode or warning light in this wire to make it work.

Hope this new way will help.

I did try this on a recent conversion I helped a friend with so I will add this update.

Take the old generator bracket off and flip it end for end then rebolt it to the block using the same holes.
You will need a piece of all thread rod to fit the alternator mounting hole about a foot long and 4 nuts and washers. Install the all thread rod in the bracket and let it run long toward the front. You will want to have put nuts and washers to hold this rod in place in the bracket and put the alternator on the piece of rod that is running long to the front of the bracket.
It will look like this when you have it installed properly.
From the front..... ..... ..
Nut; Washer; Alternator; Front ear of bracket; Washer; Nut;..... ..... . Nut; Washer; Rear ear of bracket; Washer; Nut.
This set up should put your belt in the correct alignment. The top adjusting bar fit right up to the alternator adjusting bolt it is just on the rear side. No problem.... install the bolt from the rear through the adjusting bar and into the alternator.

Hope all this makes sense. If not some one let me know and I will try to explain it better or get a picture of what it looks like.

The first type and the most common one is with a external resistor. They put the resistor on the out side of the coil so they can bypass it and give the coil a full 12V shot while cranking for easier starting. That point is really mute on these tractors because we do not use the starter relay needed to do this. Remember I told you the starter relay from the car parts store does not work on these tractors with a grounding starter switch. While these coils are easy to use; work very well; and may cost less; I try not to recommend them because of the added resistor needed in the wire. If you do not have the resistor that goes with your coil it will not work properly and you will be replacing coils because they over heat and burn out or do not get enough power. This is why I recommend you use a coil with the internal resistor. It is just easier on me to tell you how to wire the internal resistor coil. If you get a coil that needs a external resistor and get the proper resistor to go with that coil you just need to wire the resistor in the wire from the terminal block to the coil so it cuts the power to the coil. This resistor will get very hot during use so mount it so it does not burn any wire coating or such.

The second type is a 12V coil with a internal resistance caused by extra wiring in the coil. It will be marked “No External Resistor Required” or something similar. If it is not marked it is NOT a internal resistance coil and will require a external resistor. This point is very important if you are buying a kit that has a coil included. My AutoZone store did not have this coil in stock. It is not a very common coil because like I said auto manufactures like to use the external resistor coil so they can bypass it during start up. I did find some at my local NAPA store. The cheaper (notice I did not say cheap as in inferior) brand had a part # of IC14-SB $13.99. If they do not have this one you could get the Echlin brand part # IC14 but it cost more.

So now we have all our parts installed on the tractor and it is time to wire every thing together.
Print out this wiring diagram so you can follow along.

While we will wait till last to install and hook up the battery lets start with the biggest wires first.

Battery cables;
Battery negative post to a good engine ground
Battery positive post to the left side of starter relay
Right side of relay to starter

10 Gauge wire;
Alternator battery post to the left (battery) side of relay. You can put your amp gauge in this wire if you are going to use one. If you hook it up wrong and it reads backwards just remove and install the wires on the opposite post of the gauge.
Left (battery) side of relay to the hot side of the terminal block.

All the rest of the wires are 12 gauge. While you may be able to use 14 gauge wire I always use 12 gauge wire as it does not cost much more;

Hot side of terminal block to……..
Key
Inline fuse and then to light switch and lights.

Power only with key on side of terminal block to…..
Other side of key
Positive side of coil. This is the wire you need a resistor in if you are using the 6v coil or the 12v with external resistor.
I post on starter relay (Note; if you have the 3 post starter relay just leave this wire off)
#1 of F post on alternator. This is the wire you need a warning light or a one way diode. Some way to break back feed from alternator.
Volt gauge if you are using one.
Inline fuse and then to fuel gauge

Almost done. Now we need a 12 gauge wire from…….
The #2 or S post on the alternator to the battery post on the alternator
Fuel gauge to the fuel sender
Negative side of coil to distributor points
S post on starter relay to starter switch on the transmission

Now you can hook up the battery and start it up. Check to see that the fan belt is running correctly. Take a volt meter and set it on 20 volts DC. Put the red lead on the positive battery post and the black lead on the negative battery post. You should have a reading of 14 volts give or take 0.5 volts. If so you are charging and it now time to set back and enjoy you new 12v system.

John in Louisiana

Thanks for the effort, I am sure it will help numerous old iron users in the future. This write-up is now saved as a file and will be printed out and put into the binder for the old girl. In fact, I am going to e-mail to a friend of mine with an old Allis AC that has a butchered wiring harness that needs to be straightened out before it lights off and burns something up.

For the less inclined types the complete conversion sets are probably the easiest way to accomplish the goal. After piecing several conversions together over the years from whatever was to hand at the time this write-up really ties it all together. My hat is off to you for the effort.

Now go out and hop on a tractor and take a ride, you deserve it..... ...

thanks,

Mark

It will save the entire post to you computer.

Now..... ..
I did think about sending this to kim so it can be added to the articles.

On second thought after typing what I was going to say I think it is best to do it this way.

Send me a e-mail at
jpfmcf at yahoo dot com

I can tell you some things I am thinking about as to posting this and you can give me some feed back.

John

You do good work dude.

This ought to get published and added to the "Manuals" section so that it doesn't get lost in the archives. This will be useful for lots of folks for lots of years.

Mark