Ford 8N - Electrical problem. No juice and ammeter buried into negative side.

[tmac196]

This tractor is a 6V system. 1951. New armature in generator and new battery (before the gennie was found to be at fault) and a new voltage regulator 8 weeks ago. Today I received the dreaded text while at work from my spouse, "The 8N is dead, again". This is the second most valuable piece of hardware on our spread as it pulls the manure spreader.



Upon my return home, I find the ammeter needle buried to the left (negative side) which is most unusual (It's always been zeroed) and no needle movement when the ignition switch is keyed on (also unusual-it typically deflects to the negative side a tad).



The is no juice to the electrical system and , indeed, the tractor is "dead" as my wife suggested. I have no hygrometer to test the new battery and an inspection of the wires and harness reveals no obvious causes. I put the charger on the battery, but the charger gauge needle reads that it is not receiving much charge.



I do not have a voltmeter. Any ideas as to the cause of my problem and the next steps I need to take to correct it will be most welcome.

tmac

 

[murphy1244]

something is draining your battery.

 

[MIKE R]

Check that your regulator is not screw up and tryin to run the geny like the DC motor it is. If it hot without being used theres your problem. Battery back feeding to geny. Cut out points in the regulator fused together.

 

[94BULLITT]

I agree with Mike it could be the regulator.

 

[CobyRupert]

I have nothing to offer, but am wondering: Are these positive ground 6V systems?

 

[94BULLITT]

I have nothing to offer, but am wondering: Are these positive ground 6V systems?

Yes:tractor:

 

[tmac196]

Hmmm...I just went out and put the charger back on the battery and stood there and watched. The charger needle pegs up at the 0% charge range as soon as I connect it to the battery and hums loudly (as if charging hard) for a minute or two. Shortly after this the charger gives off a loud click and the needle drops off into the 100% fully charged range. After a few seconds of this the cycle repeats itself as if there is a short and the internal mechanism of the charger is cycling to prevent it from overheating. The charger and the battery alligator clips do become warm during this process.

I will obtain a new voltage regulator and temporarily disconnect and charge the battery and report back.

Why would a new voltage regulator suddenly fuse it's points? Because it is junk?

tmac

 

[tmac196]

Update:

I disconnected the battery cables and it was drained of all charge. I put it on the charger and disconnected and removed the voltage regulator. The voltage regulator, when shaken, makes a noise as if a tiny piece is loose within the steel housing. I was able to easily start the tractor once the battery was sufficiently charged. The ammeter remained buried to the left during this process.

Next, I installed a new voltage regulator (Borg-Warner) whose housing is too big too fit on the firewall so it must be returned. The engine fired up again and I ran it for 15-20 seconds watching the ammeter remain buried in the negative the whole time. When I attempted to remove the voltage regulator after this brief use, I scalded my fingers on the hot ARM and FLD terminals much to my surprise. The BAT terminal was not particularly affected. I admit that in my haste I forgot to polarize the regulator, but should that matter and should it cause the regulator to heat up so quickly and significantly?

Have I installed the wrong wires on the wrong terminals and burned up my old voltage regulator in the process? If the VR gets this hot with simple use, wouldn't it have taken less than seven weeks to fail? Should a VR ever be so hot?

I will take the old possibly broken VR back to the place where I purchased it tomorrow and have it tested. More to come.

Any and all discussion would be welcome.

tmac

 

[Soundguy]

wow.. wish i had seen this post sooner before everyone started buying parts and burning things up without doing ANY testing.

1, with battery disconnected.. if ammeter stays pegged. it needs repalcing. if nothing else.. it's useless. it also COULD be/have been the souce of the problem. IE.. a short to ground AT the ammeter.

2, if the battery will charge up, you can remove the wires from the genny and the vreg and should be able to start her by taking a wire from the batter and putting it to the side of the key switch not connected to a resistor or running to the dizzy. disconnect that wire that normally runs tot he key to isolate the rest of the system.

that should make her start and run.

next.

get a new ammeter if your old one is pegged with battery out.

once you get the new ammeter installed. we can troubleshoot the genny and vreg. even if you don't have a vom or volt meter. we can do it using the ammeter and a test lamp. which you could make if needed.

you can actually make a genny charge without a vreg, running a full field test.

same deal.. you can motor a genny to test it.


PS.. you do not polarize vregs. you polarize generators.

you only have to pol' them if you change polarity..or change out the field pieces. or drop them alot. or have not run her in a long, long, long time.

if you accidentally ground the field on a 8n genny.. it will charge max and burn up and make wires hot. or if there is a short at that old ammeter.. it will make some wires hot.

either way. if the ammeter stays deflected when bat out. replace it and we can troubleshoot it. ammeters today are really a shunt voltmeter anyway. ie.. vdrop across a shunt... etc.

 

[94BULLITT]

Are you sure you hooked the regulator up right?