TE-20 negative charge?

[Brad Bliven]

Hey guys, first time posting to the forum so forgive how green I am...

I have a TE-20 which my father purchased in 1970 and I am trying to restore. The first thing I noticed was that someone converted it to a Negative ground 6v system. Everything else is pretty much original.

I have been working on getting the starter to actually start the tractor instead of hand cranking. So far with a new battery and starter switch I can get it to barely crank over. With patience I can get it to start the tractor. Is this normal? I have not replaced or had the starter checked yet. It cranks a quarter turn and stops, then I try again and another quarter turn then it stops, after several tries it might pop off and run.

Also I am not sure if the generator is charging or not. When running the ameter moves like it should but at a normal RPM it displays -10 instead of a positive number. Is this normal for a Negative ground conversion or is my Ameter wired wrong or is there an issue with my generator? Any insight is appreciated.

 

[Jeff-oh]

Welcome to the board.

1) The systems were normally Positive to ground. How do you know it has been converted, as opposed to just putting the battery in backwards.

Check the polorarity on the ignition coil. Which side of the coil is connected to the distributer? + or -. That will tell you what should be ground.

2) If truly neg. to ground, was the generator field properly polorized? I could see this being an issue. Do an archive search on polorizing a generator the procedure has been posted many times.

3) 1st thing I would do is dis-coonect every wire (one at a time) in the circuit and clean/polish every connection. Re-assemble and coat with a di-electric grease. Bright and Tight should be the rule. 90% of slow starter turns with a 6V system can be traced to dirty connections and resistance.

As a test you can breifly jump a 12V battery to the system. Connect 3 of the clamps then touch the 4th clamp to the 6V battery as you engage the starter... Probally pop to life. This a good indication of dirty connections.

Visit www.FergusonTractors.org and under the resources tab are the electrical diagrams.

I would convert to the proper 6V Positive ground to avoid confusion in the future.

Again, welcome to the group.
FENA

 

[wisbaker]

Be careful hooking a 12V battery to a six volt system at the battery, good way to smoke points/condenser and mess up your voltage regulators way of thinking. Might better jump directly to the starter, less of a chance of messing something up. I agree with the other guy- dirty connections and corrosion inside your battery cables OR over the years someone installed cables for a 12V system, that are not big enough to carry the load in 6 volts.

 

[wisbaker]

Another idea go to the 8N board on this site and search for 50 tips for a N series owner, a lot of what they advise applies to your Fergie

 

[John(UK)]

Make sure that all the wiring terminals are clean and bright, especially the Battery Cables. do not use emery paper to do this or you will remove the metal coating. Move the Ground lead from the back of the Dash panel to one of the bolts close to the starter. Check that the battery cables are the very heavy gauge cables not the thin type that you use on a car or small truck. It won't be converted to negative ground...it will be someone has just fitted the battery the wrong way around, it often happens. The ammeter reading the wrong way should be fixed when you turn the battery around, if it does still read the wrong way, just reverse the wires on the back of the ammeter.If you still have problems with the starter not wanting to turn the Engine it could be the Starter needs cleaning, or the brushes changing because they are worn. If you remove the inspection band around the Starter you should see if it is sparking a lot when you try to start, if it sparking then it does need cleaning.It can also be the Starter switch on top of the Clutch housing may need adjusting, slacken off the four screws that hold it to the top of the housing and slide the switch gently for-wards, this will make the contacts touch harder, but don't force it forward or it could break the switch when you press the Gear lever hard. To check the Generator and if it is charging it will show on the ammeter and you say that you are getting a reading although it is the wrong way around, so it appears that it is charging, but to check it for sure, run the engine at half throttle and remove one of the battery leads and the engine should keep running if the Generator is charging. If you want the information about cleaning and checking the Starter, email ...John(UK)[email protected]

 

[Brad Bliven]

Thanks for the advice. I will clean and replace all wiring needed. I know I have problems with old wires and one battery cable is for automotive use. I bet that takes care of the hard starting.

Regarding the negative ground wiring. I thought I had ran accross a negative ground wiring diagram once which led me to believe it was an option. The positive terminal from the coil runs to the distributor so I figured the negative ground was oky since this was switched as well.

From what I read here I should change everything back to original and replace the old wiring and terminals before I try again.

Thanks to all.

 

[John(UK)]

Actually the wiring is the same on a Negative Ground and a Positive Ground, but the exceptions to that is anything that is polarity sensitive.
The battery cables need to be very heavy because of the amperage used by the Starter on a 6 volt system, the thin cables are just not heavy enough, especially in colder weather. You should change everything back as you say. You MAY need to re-polarize the generator again, maybe not, some work some don't, possibly better if you do though.
The feed wire to the coil from the ignition switch should be attached to the opposite terminal to which the Ground wire is attached to the battery. If there is doubt about this, just test the spark and then reverse the low tension leads on the Coil and use the configuration that gives you the best spark. Set the points to .012" and the Plugs to .025-.028" Champion 7 or equivalent. The ignition is set to fire number 1 at TDC if it has a Lucas Distributor.
John(UK)[email protected]

 

[Jeff-oh]

Positive Coil terminal to distributer is standard for a positive to ground system. As manufactured there.

Jeff

 

[Grits]

Hi Brad. 6V systems work just fine when they are right. Mine is converted to negative ground and it works just fine that way. So don"t blame those things.

At 6V a little resistance on any contacts eats up a lot of the zing so you have to keep electricals clean and good. Ditto what others have said about battery cables, terminals, etc. DO check the starter brushes - my TO-20 cranked poorly when I got it and the brushes weren"t moving freely and were at a considerable angle and not contacting all across the commutator; make sure they are long enough, free-floating and good contact all across the face and that the commutator is smooth, not deeply scored in some places, burned, etc.

I converted mine to neg ground since I use some various electronics I"ve built and most conventional electronics these days expect neg ground. There was no particular reason to keep it pos ground. While some DC motors are reversible with polarity, the starter on these is NOT. A couple of days ago someone was insisting that the voltage regs are not compatible for neg ground, but the old "coil and contacts" regulators don"t care a thing about polarity.

 

[lee thomas]

If you have a TE 20 you will have a lucas starter the bushing in the starter are probably worn and the armature dragging .
This will keep the starter from turning as fast as it should to start.

 

[ShadetreeRet]

With all due respect to someone down the line, but you ain't gonna catch ME connecting a 12 volt battery directly to a 6 volt battery, even briefly! I connect the jumpers to the 12 volt, ground one jumper and touch the other to the starter terminal where the cable attaches to the starter. This will spin 'er over without shooting 12 volts through the entire electrical system.

 

[Anonymous-0]

If the negative is to earth, then the negative side of coil should be to the distributor otherwise you have a minus to minus ignition system. This may also fix the ammeter. or change it to what it was + earth + coil to distributor.providing the previous owner has not done some other funnies.

 

[Brad Bliven]

All, again the vast knowledge on this forum has proven very valuable. I switched my 48 TE20 back to Positive Ground at the battery and replaced a #4 automotive battery cable with a #1 cable and bam!! The old girl starts like a champ and the Ammeter is showing positive. I can't believe how good it starts and the lights are now brighter than a candle!! Thanks to everyone who contributed.