TO30 12v - 6v hybrid electrical system

Hi guys,

Its been a while since I"ve posted anything - like 5-6 years. And the last time it was all about a TO20 with a #2 exhaust valve issue and a PTO shaft that wouldn"t come out. The TO20 is still the same and runs good with all that.

I now have a TO30 I bought this spring that has been working just great. With my ability to create excitement I decided to run it out of gas and cranked on the starter because I just did not believe it was out of gas. Those of you that know anything about 6v starters on a 12v charging system know what happened - yep I fried the starter that came from the factory with the tractor. Got a new one and put it on. Problem solved - it started just like always. Decided on a 6v now that I know not to just keep cranking on it.

Well now the new challenge. It ran for 2-3 minutes and then died. Wouldn"t start. Waited 20-30 minutes and it starts and does the same thing. This is all stationary - no movement and no load. After reviewing all of the info on the forum about this situation I figured I would start with the 6v coil. So far I have replaced the 6v coil, 12v-6v ballast resistor, condenser, reworked all the wiring to make sense of it being sure to terminate it all just like it was just shorter runs and fewer points of connection. Also made sure all the connections are cleaned and all that stuff. Now it won"t start.

There is this thing that looks like a small voltage regulator that is between the alternator and the ballast resistor. It is old - like original type old. It has what I think are 2 different sizes of resistors on the back and inside the removeable housing is a magnetic solenoid that apparently switches between what resistors are used. The input is from the FLD connection on the alternator and the output is to the 12v-6v ballast resistor and to the key switch 6:00 position. I have checked all the rest of the wiring.

The system is a 12v charge with negative ground. 6v coil - is going to distributor and coil + is to the ballast resistor. The alternator is a Delco-Remy #1100704 37A 8020 12VNEG It has markings for BAT, GRD, R, & F. It has 2 wires; 1 from the BAT to - ammeter and the other from the F to the FLD on the strange little black box. The - ammeter is also connected to the key switch and the + ammeter is connected to the + battery cable. The key switch has 4 positions CW from 12:00 - 3:00; Off-12:00, Ignition-1:00, Ignition & Lights-2:00, Lights Only-3:00. Looking at the back of the key switch there are 3 connections CCW from 12:00-6:00; lights-12;00, - ammeter-9:00, little black box-6:00. This little black box connection is the same as the one to the ballast resistor.

With everything connected and the key set on "Ignition" the points have a lot of fire and spark when touched by a screw driver. However, when I engage the starter the point spark really drops off or goes to nothing. I have checked gas going to carb - yes. And I did have to pull distributor to put in the new longer starter. Used the old thumb on #1 to get it back in the ball park. And I know not to "CRANK" on the starter.

I am wondering if the black box is some sort of cut-out switch or some sort of selectable voltage regulator that is activated when the alternator is turning and sending voltage through the FLD.

I posted a picture. The connection to the black box in the upper right is from the "F" on the alternator and is stamped "FLD". the output is on the upper right and goes to the ballast resistor and the 6:00 position on the back of the key switch. The green wire coming from the right of the ballast resistor goes to the + 6v coil. I have several other pictures of all of this that I can post if needed.

Thanks for any ideas you may have.

Stan

The black box you describe is the Voltage Regulator that was part of the original generator charging system.

Let me get this straight: You have a 12 volt two wire alternator; A 12 volt battery; 6 volt starter motor; 6 volt coil and a resister to drop the ignition voltage to 6 volts? I don't understand why you want the benefit of a 12 volt system, then halve the ignition voltage?

"With everything connected and the key set on "Ignition" the points have a lot of fire and spark when touched by a screw driver. However, when I engage the starter the point spark really drops off or goes to nothing."

Click to expand...

Obviously not fuel. Either the starter motor is pulling excessive current or you have a short in the starting circuit? Is the battery OK or reaching it's "use by" date?

First, the alternator... The alternator is an early Delco that requires an external regulator. Someone has substituted what looks like a Chrysler regulator. Need to get it running before diagnosing anything further on the charging system.

You'll want to start with a fully charged battery, like slow charged overnight at 5 to 10 amps. Get everything ready and put an analog volt meter between the + terminal and ground. With the points closed, switch on, the voltage should be around 6 volts. Next, ground the - terminal with a jumper wire, and take a voltage reading while cranking. The needle will bounce with each compression stroke, but if it's falling below 2 to 3 volts, there probably won't be enough to fire the plugs.

If I were going to make a change, I would replace the 6v coil with a 12v 3 ohm coil (Napa IC14), no resistor needed.

That should provide sufficient spark during cranking. Also be sure the rest of the ignition system is right, so the spark gets delivered to the plugs, not just coming out of the coil.

Once it's running, go back to the alternator.

Before starting the engine, check for battery voltage at the "Bat" terminal on back of the alternator, and check the belt for tightness and wear.

Start the engine, and with the engine at fast idle, (1000+RPM), check the voltage across the battery. It should be 14 to 16 volts.

If it's over charging the regulator can be adjusted by bending the spring tab under the cover.

If it's not charging, jump the "F" terminal to the "Bat" terminal. The voltage should go up, the alternator will whine and slow the engine. If not, the alternator is bad.

Or, replace the old style alternator and regulator with a 10SI internally regulated alternator. It will take some wiring modification, but it's an easy fix, simple and neat.

Hey Bob,

That"s the way it came to me. Why someone only takes the conversion halfway is beyond me. It looks like all I need to do is get me a 6v generator and I have it back original.

Battery is good. Since I brought it home the last of March it has started the first time every time with no effort - even with 3-4 weeks between usage. On my 20 I pull the battery ground to make sure the battery stays charged. I have never done that with this one. Battery appears to be a year old.

I take your word for the VR. All the ones I have seen or read about are twice as big and have 3-4 terminals.

Just me thinking aloud about this - If that is the original regulator for the 6v system then it is restricting the alternator output to 6-8 volts then it goes through the ballast resistor that has no smarts and basically gets cut in half. Surely something is wrong with my logic!?!?!?

Steve,

Thanks for the details. Your info on the alt/VR corresponds to some of the research I found - older style alternator with an external VR required. I have to work on another project tomorrow. I will charge up the battery and take it through the steps early next week and let you know what I find.

Stan

Why has a fuel problem been eliminated ? Sounds a lot like fuel starvation of sorts .

I would drop in a 12V coil with an internal resistor and run a file past the points...
By now the engine has been cranked to death and cold cold compression might be low. Pull the plugs, squirt in some oil, cover the holes and crank over blowing out excess. Reinstall plugs and give it a shot of ether. I do not have time to waste trying to start it on gas and build oil pressure to the dry bearings. I need it running at the first crank. 1/3-1/2 throttle to get past the stumble of a slow idle and oiled down cylinders.

"I don't understand why you want the benefit of a 12 volt system, then halve the ignition voltage?"

Because he is using the original 6 volt coil.

If the 6 volt coil is operated direct from 12 volts it will pass excessive current which will damage coil and points.

To prevent this over current in a 12 volt conversion you can either change to a direct 12 volt (no external resistor required coil) or add a resistor to drop the coil voltage to 6 volts.

A coil is a transformer with one side of the primary and one side of secondary tied together.

A 6 volt and direct 12 volt coil (not one marked 12 volts external resistor required)are wound with different primary/secondary turns ratios. There is no extra resistor packed into the 6 volt coil can. The design of the two coils allows them to operate at different input voltages, but output the same high voltage to the plugs.

Agree!

Finally a resolution to this item after only eleven months - the things that interrupt working on our tractors.

Those of you that are looking to buy a well running older tractor - take note.

After doing all the following:
completely redoing and replacing the essential wiring,
replacing the starter I screwed up,
other replaced parts include;
ballast resistor, coil, condenser, points, rotor,
ammeter, oil pressure gauge,
sediment bowl fuel filter,
exhaust pipe clamps and reworking the adapter for said item so the clamps work correctly,
adding a temperature gauge
and almost completely cleaning out the after-market Cyclone Air Cleaner so air can get to the carb

the old well running TO-30 I bought early last summer is running like it was when I bought it.

Oh yeah - forgot about having to retime it because I screwed that up when I replaced the starter amd removed the distributor without marking it.

Now I just touch the starter and it roars - or more accurately purrs to life. What a feeling!

Thanks so much for all the help and encouragement. There is so much detailed and accurate information on this forum. And of course a full set of manuals helps too.

Charles in Aus,

I could not get your question out of my head. After I got it starting again I went where your question sent me. Replaced the sediment bowl fuel filter - don't know how gas was getting to the carb the screen was completely coated with corrosion. Also cleaned what turned out to be an aftermarket Cyclone Air Cleaner so the the carb could get a lot more air. Those two things really made a huge difference in how it runs.

Please keep asking the obvious questions - It really helped me get this thing running the way it should.

See the topic:
TO-30 Air Cleaner - What is it?
for the rest of the story.

It was started on July 8 or 9, 2015.

Thanks for the feedback Stan , it's always good to know when your instincts have proven correct .
I find that there is one cardinal rule for determining whether a problem is due to fuel or electrics . When the running sounds rough and if you feel like the engine is dying pull out the choke , if the engine recovers , even for a moment then the problem is most likely fuel , otherwise it is down to the nasty ' Electrickery ' .