55 TBird not charging

[Shoovel]

I’m helping out a friend who has a 55 TBird and it’s not charging.
It is a 6 volt + ground system. Unfortunately he does not have to much past info on the car. It has a fairly new looking generator and regulator and a new battery. I polorized the field, still no charge. It’s been a long long time since I worked on a generator system. I took the cover off of the regulator, no rust or corrosion. The generator puzzles me. It has a (F) terminal & (G) terminal on the side and then a larger wire on the back of the generator. I know the F is for field, what is the G terminal? What’s the best way to test the generator and regulator?
Thanks
Tom

[Crankster]

The shop manual would be best, because it's important to follow the connections and step procedures (for a Ford generator) in order to determine which is at fault, and to avoid damage to the regulator.

I think you might find some shop manual scans here, I was looking at some stuff the other day.

http://www.vintagethunderbirdclub.ne...912590ad27d68f

There are some quick things to look for. The brushes sometimes will get hung up in the holders and lose good contact with the commutator, even if they are not worn.

[dmsfrr]

Originally Posted by Shoovel

. . . The generator puzzles me. It has a (F) terminal & (G) terminal on the side and then a larger wire on the back of the generator. I know the F is for field, what is the G terminal? . . .

G is for Ground. The large terminal on the back is for the Armature / output. Double check that it hasn't been arching to the head. If the generator has been replaced the Armature stud can be very close to the head. (photo 2)
The original generator on a '55/'57 T-Bird has the Armature terminal on the lower half of the rear plate, not the upper half like the more usual generators. There is a kit available to relocate the terminal stud to the safer lower position.

Another potential problem if the generator was replaced... the pulley on the front is T-Bird specific. The groove for the belt is closer to the body of the generator, so the belt lines up with the crank & water pump pulleys. Photo 3 = 'full-sized' car, photo 4 = T-Bird

To polarize the charging system...
... before you start the engine, remove the Field wire from the voltage regulator and brush the end of it across the Battery terminal of the voltage regulator, then reconnect the Field wire to it’s position on the voltage regulator.

[rotorwrench]

Most electric shops would check the battery condition first since that is an easy check. Check all connections between the generator and the regulator for condition and security. Check the generator and it's drive belt for condition and security. If no problems are found then an output test would be next to see if the generator still functions. It should put out it's rated amperage limit if functional. If its working then the generator control unit (VR) is next item. Most of the later VRs are not repairable to a large degree. Only the old ones are really designed to be repaired but it takes all the necessary test equipment to check and adjust them after repairs are completed. The information for repairs and tests can be found in manufacturer's repair manuals or Ford specific manuals that cover the make and model affected.

[Shoovel]

I was able to do more testing today.
1) Disconnected the connectors off the gen. Disconnected the wires on the regulator. The Field wire and the Arm wire have continuity with the corresponding Field and Arm wire on the regulator.
2) The Ground wire on the generator has no continuity with the ground bolt on the regulator. (After I polorized the gen, I ran a jumper wire from the Ground wire on the gen (hooked up) to the ground bolt on the regulator. Still no charge)
3) New battery 6.1V
4) I disconnected the Field wire from the gen, fired it up and applied power to the Field terminal. No charge.
5) I disconnected the Field and Arm wire from the generator and disconnected the belt. I put a jumper wire from the Arm to Field terminal and applied power to the jumper wire. It became a motor and spun.
Makes me believe the generator is ok, but should it have charged when I put power to the Field terminal?
Any other thoughts.
Thanks

[Crankster]

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One reason I recommend using a shop manual or equivalent is because 1. Generators are not commonly used anymore, and what I mean by that is they are "pretty reliable", meaning in practice they seem to work just long enough to where you've (Or at least me anyway) forgotten all those fine details about testing and troubleshooting. And those details are important, while the generator as a species is pretty dang tough, it's easy to roast or burn the voltage regulator windings or contact points. Your Uncle might "remember" how to test a generator - but he had a Chrysler, which uses a different method of grounding the field.

I can ASSUME that troubleshooting a 6 volt Ford generator charging system is virtually identical to the 12 volt Ford generator ... but I don't know that, thus my previous admonishment to "RTFM!!".

The fact that the generator wants to motor when you've jumpered the ARM and FLD and apply voltage is a "good" sign. But ... it isn't definitive. The first step in my '64 shop manual for generator or charging system testing is the "output test". Current, not voltage. The idea is split the charging system down the middle - is it the generator, or is the regulator at fault? (or the wiring itself).

Similar to what you did, it says to jumper the ARM and FLD terminals (after removing all the regulator wiring at the generator itself). Connect the ammeter + POS connector to the jumper wire at the generator, and the - NEG ammeter connector to the + POS battery terminal. Start the engine. The current (amperes) should spool up to at least the rated output of the generator. Only perform this test long enough to see if the generator is providing current. The generator "should" be OK.

I will say a couple years ago, the generator on my truck passed this test, with burnt brushes, they had never been sanded to fit the commutator when installed. I noticed the voltage output sagging under load on a long roadtrip. Eventually, the GEN light illuminated. I had to cut short the road trip and return home for other reasons, but by mileage I later determined I would have had the GEN light most likely somewhere in rural SE Wyoming (in a blizzard, as it happens). I'm really glad that didn't happen.

Back home in my garage, it would also "motor" fairly well on the bench. It was only upon removing the generator backing plate to inspect that it was obvious what the problem was. I learned something - can't really trust a "rebuild", even from a shop. "Trust - but verify".

[rotorwrench]

I've had to attach abrasive paper on the commutator in order to seat brushes on aircraft starter/generators when replacing brushes. It works but getting the paper to stay on can be tricky. I cut the paper to fit the circumference and 2 X the width. Fold the width in half then apply tape inside the fold to hold it on to the commutator. Turn it for a seating effect. If it needs more then turn the abrasive paper over and turn it some more.

The mica may need to be under cut between the segments on the commutator. If the insulation there touches the brushes it will prematurely wear on the new brushes.

[Shoovel]

So today.
I also watch Moss Motors on YouTube.
I disconnected all connections on the generator. I put a jumper wire from the Arm terminal and the Field terminal and connected a volt meter to the jumper lead. Fired up the car and it showed 12+ Volts and climbed rapidly as I accelerated the engine. This leads me to believe the generator is ok. I’m leaning now towards the regulator. I tried cleaning the points (3) but no change.

[Crankster]

Try putting at least some kind of load on it when you run that test, maybe a spare headlight, say. In this case maybe a 12 volt headlight. Does it light up nice? Remember, the output test - numero uno in the book, is testing for current, not voltage. I agree too the generator is "probably" OK, but the shop manual procedures are very good about their step procedures. I think it's setup this way because voltage & charging isn't the whole story, it has to be able to supply enough current, or charging won't happen regardless of indicated voltage.

A voltmeter alone won't load it down? On the other hand, I've no idea how the ammeter knows everything is copacetic during an output test either. Somebody here care to 'splain that? I'm just barely dumb enough to follow instructions, sometimes.

[rotorwrench]

Light bulbs are made for specific voltages. If the system voltage goes too far above that, the bulbs tend to burn out pretty quick. A good meter tells all a tech needs to know.

The modern reproductions are disappointing when compared to old NOS parts. Even old aftermarket parts are better made but will they still function properly? It's all a crap shoot now days. It's good to know how to test and have the equipment to test this stuff but not everyone wants to. Having an auto electric shop nearby is great but there aren't as many out there now as there used to be.

[Crankster]

Originally Posted by rotorwrench

A good meter tells all a tech needs to know.

Well sure, but even the finest voltmeter ever made can't measure the current output in this earliest step of the troubleshooting. I think the generator output test is setup by way of a logical process of elimination, "go/no go", first thing out of the gate by determining if the generator itself can provide sufficient current, or not. If it can't, there's no point in continuing further. If it passes this test, then the voltage will by necessarily follow, and both current and voltage are handled by the regulator anyway.

[rotorwrench]

Yes, they are both regulated or at least you hope they are. It takes better equipment to test the current regulator and properly adjust it and the voltage output. A volt meter only tells part of the story but if that's all a person needs to know then it did its job.

The resistors can go bad. The pole coils can go bad. All this stuff can be tested if a person knows the specs. Most folks just replace the unit and hope the new one does the trick. My old Lincoln Mercury Overhaul manual for the 49 thru 51 cars has the procedures using the old Sun test equipment to run a full diagnostic. This stuff is not as commonly available as it once was.

[KULTULZ]

I hate to get into this first stage of a food fight, but ...

Your first consideration is the state of the BAT. You read the V with engine off. Does it read @ spec? If not, correct. The BAT is the heart of the system. If it will not take and hold a charge, it puts strain on the GEN/ALT leading to possible failure.

Start engine and read V again. If increased V, then the CHARGING SYSTEM is functioning but further diagnostics (following WSM or other certified repair info) may be needed to confirm correct operation.

You also have to take into consideration VOLTAGE DROP and STARTER DRAW.

Jumping around is not going to solve the problem(s). A TECH cannot afford to go about it in this fashion, as he/she/it/mutant is on flat-rate.

rotorwrench's POST #4 pretty well summed it up (IMO).

DISCLAIMER - The above is IOM ... ...er ... dyslexic ... IMO and your mileage may vary.

In a GALAXIE far, far away and many time warps ago, this was the first step in a proper engine tune-up. She ain't gonna run with no electrons, neutrons and morons ...

[KULTULZ]

Originally Posted by dmsfrr

G is for Ground. The large terminal on the back is for the Armature / output. Double check that it hasn't been arching to the head. If the generator has been replaced the Armature stud can be very close to the head. (photo 2)

The original generator on a '55/'57 T-Bird has the Armature terminal on the lower half of the rear plate, not the upper half like the more usual generators. There is a kit available to relocate the terminal stud to the safer lower position.

Another potential problem if the generator was replaced... the pulley on the front is T-Bird specific. The groove for the belt is closer to the body of the generator, so the belt lines up with the crank & water pump pulleys. Photo 3 = 'full-sized' car, photo 4 = T-Bird

THANX! for the BIRD SPECIFIC factoids ...

[Crankster]

Originally Posted by KULTULZ

I hate to get into this first stage of a food fight, but

Your first consideration is the state of the BAT.

?? "Food fight"? Nah. Seems like an excellent discussion to be had by all to me, it should be obvious from the answers provided everyone here is on board with using the shop manual and by necessity checking the battery from the git go. It's also a brand new battery.

I agree generally speaking it is difficult to lead people to the "one true path" of troubleshooting righteousness*, and actually read the g@&$amn manual, but, that's not news. Good Luck with that, you should know better than that by now!

* "voice crying in the wilderness" maybe?

[KULTULZ]

"voice crying in the wilderness" maybe?

That would most likely be me being sexually molested by BIGFOOT ...

[dmsfrr]

I'd like to offer some shortcut tricks to trouble shooting the generator and voltage regulator, but the 12v converted '55 I have was charging well when I got it.
It hasn't crapped out on me yet (knock on wood) and I haven't been forced to look into it.