Wrong Alternator?

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domdart

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I have a 68 Dart that came with a slant six. I put a 340 in it from a 72 Duster. I got a V8 electronic ignition engine harness when I did the switch. My alternator quit charging last year on the way to Carlisle. I got a used one at the show and made it home. I put a new reman in it when I got home and it just stopped charging during the first ride of the year today. How do I know if I am using the correct alternator? The first pic shows the type I have been using.
The second pic shows the type that comes up when I search for a 72 Duster 340. Which one is correct? Thanks FABO.

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Depends, LOL. You must determine what type VR you have. The ORIGINAL OEM regulator for 69// earlier used a single field terminal alternator. The later one you pictured will work if you ground either field terminal and hook the rest up normally

If you have converted to the 70/ later "flat" electronic VR then you MUST have an isolated field alternator, sometimes INcorrectly called "dual field." (2 field terminals.)

The second type called a squareback is BETTER because those type normally charge better at low RPM. Again, you can ground one field terminal and hook it right up
 
Your first pic is a "one" field wire "round back" alt that typically is regulated by a voltage regulator that looks like this (mechanical or electronic)
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Your second one is a "two" field wire "square back" alternator that typically uses a voltage regulator like this

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The wiring for each is unique.

So it really depends on the harness you have.
 
If the car has the regulator for the one on the left, then you can use either. Ground the second field terminal.
If the car has the regulator with the triangular connector, you must use an alternator with two insulated terminals (like the one on the right).
 
I bought one the other day and came up with the same situation. Since it was going on a restoration, I decided to take the original and have it rebuilt locally. I did notice On the newer square back that they had clipped one of the field wire spades off so that you cannot plug anything on it. I kept it to use on another car that will need a alternator in a few weeks. It uses the older style VR and is a 2 wire car.
 
I have the voltage regulator for the round alternator, so they match. My harness has the ring connector and the single green wire. I searched the forum and learned that others have gone thru a few reman alternators.
 
It's easy to test enough to at least get an idea of the trouble. Start by taking a jumper wire and remove the green field wire. Check with a multimeter to ground and make sure there is continuity. Hook your jumper wire / alligator clip lead to the battery, and touch it to the alternator field terminal. In subdued light you should be able to see a small spark.

Next connect that terminal to the battery with jumper. Start car, slowly bring up RPM. Ammeter should start to show a charge. Best to also monitor battery voltage
 
I have the voltage regulator for the round alternator, so they match. My harness has the ring connector and the single green wire. I searched the forum and learned that others have gone thru a few reman alternators.
The only way to use the one on the right (with two insulated field terminals) with the voltage regulator and wiring on your '68 is to connect one of the two terminals to ground. That's how the circuit through the rotor is completed.
There were also roundback versions with two insulated terminals (1970-71). I bought one from a junkyard when the bearing siezed on the one in the car.
Did this at a friends house using what her dad had on hand. It still works fine. Its on my shelf as a backup.
upload_2020-6-15_21-54-32.png
 
You can also unscrew the spade connector, remove the insulator and spade then re install the screw. In essence you are grounding it to the alternator body without wires.
Its a clean look.
Screenshot_20200615-224015_Gallery.jpg
 
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Thats why I just rebuilt my original style round back and Run the older style regulator Like shown in the first pic of post #3, it is the newer solid state version however.

Every alternator I tried to buy either was a reject square back or had a dual pulley and dual fields. Got fed up With the crap sent to me. I returned it all and bought the parts to rebuild the original style myself. I had the tools to do so, so why not!

For a stock rebuild that is all that is needed. My car requires nothing more than it came with.
 
Agreed. I had "no charge" issue in Carlisle last year. Ran back and forth to Napa since I thought the spade on their rebuild was "broken". Lol
I finally got it straightened out at home with a lot of help from knowledgable Fabo members.
 
Wow with Carlisle issues last year!

I did not have any electrical issues but lost a left rear wheel cylinder on the trip north.
 
Dont mean to hi jack this thread but That must have been a mess.
I got alot of help in the showfield from Some guy from Ohio, I think, was very helpful he came over and tested everything. The problem was getting a Voltage regultor beleive it or not. He had a real sweet green, 340 Dart, original owner. Pic below. If anybody recognizes, let me know
I forgot his name, but hope to thank him again. He bailed me out at Carlisle.
Then you, Mattax and the Fabo members here finally got it properly charging since I developed a wiring problem.Thanks
Screenshot_20200615-234910_Gallery.jpg
 
This morning I tested the battery and the alternator. Both were good, so I did the "jiggle the wires test". When I jiggled the wires my wife said the altmeter was bouncing. It turns out the green wire's female connector was loose. The wire came loose from the connector when I tried to remove it. Also, the small bolt holding the male connector to the alternator was loose.
 
This morning I tested the battery and the alternator. Both were good, so I did the "jiggle the wires test". When I jiggled the wires my wife said the altmeter was bouncing. It turns out the green wire's female connector was loose. The wire came loose from the connector when I tried to remove it. Also, the small bolt holding the male connector to the alternator was loose.


Not surprised! I can not preach enough how old these cars are and their wiring. One day someone Will pay attention before it is worse, like a fire!

Glad you found your issue and look deeper!
 
This morning I tested the battery and the alternator. Both were good, so I did the "jiggle the wires test". When I jiggled the wires my wife said the altmeter was bouncing. It turns out the green wire's female connector was loose. The wire came loose from the connector when I tried to remove it. Also, the small bolt holding the male connector to the alternator was loose.
OK. Lets fix both and also clarify what the meter labeled 'alternator' shows.

The meter is an ammeter. It shows current flowing into or out of the battery. Why is it labeled 'alternator'? I really can't say? Maybe that labelling was introduced when alternators were introduced.
Anyway, battery charging or discharging also lets us know whether the alternator is working or not.
If the alternator is not working, the car will be running on battery power and you will see the needle swing toward discharge all the time. In general, the needle should be close to the center. Zero is a good thing (once the battery is charged).

Loose items to fix:
The green wire provides power to the rotor. The connector housing can be removed with a bobby pin (those still around?), a cotter pin filed, or the proper tool. Insert here.
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To depress the tab or barb shown here.
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Check the wire crimp to the terminal, and if need be replace it. If its Ok. might just need to tighten the rolled sides a little.
This one was not in the best shape - nore was the wire. Its from a harness that I retired but saved for reference and parts.
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Worse case scenario, install a replacement. There is enough slack in that wire to do this if you cut the minimum.
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Now as far as the male bolt goes, are you talking about this one, where the wire with a ring terminal attaches?
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If so, if the threaded portion is loose, its best to open up the alternator and gently tighten it.
It's relatively easy to do on the squareback.
This is a critical connection, and loose can be a problem in two ways.
One is the obvious - won't get power output The other is that if it touches the housing, then it will be a short to ground. Its mounted in an insulator, so that is normally not a problem. But if the insulator is damaged, then replace it. Again on the squareback, this is an easy fix.
On the round back it is a little more difficult to access. On the roundback all the connections are soldered and the output stud also is combined with the filtering capacitor. So on that one, might want to let a shop fix it.
 
If what you meant by the small bolt holding the male tab is this one, that's the terminal for the brush.
upload_2020-6-16_22-48-0.png


It should have an insulating washer on under it.
If the insulation is damaged or washer missing, those parts are easily available and you can replace them yourself.
Here's the insulated brush holder and brushes.
upload_2020-6-16_22-50-35.png


Stepping back, when electricity flows through the rotor's windings, that creates a spinning electromagnetic field. 'Field' is short for electromagnetic field.
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If you don't mind I would chime in with a similar question? I got my car finally back on the road and did around 50 miles of test drives.

Yesterday I went for a first test drive in the night. With the head lights on, the blinkers quickly started to get very very slow and the Amperemeter was on the discharge side, but made it home. When I measure on the alternator output terminal to a ground I get around 11.45V - same reading as on the now low Battery - this test was done with the engine RPM up to around 2000rpm.

Since I did not test the alternator before, I fear that I drove all the time just using the battery as a power source. When I installed the new battery, the needle of the Amperemeter was slightly on the charge side, now the battery is almost empty and the needle is on the discharge side.

As @Mattex mentioned above, I tried then to ground the alternator (picture post #8), still the same reading on the Alternator output. The battery went now on the charger and I would like to get a new single groove pulley Alternator. Do you guys have any recommendations for a new Alternator? Here is what I found so far, but not sure about their quality and if they would work:

https://www.napaonline.com/en/p/RSE2131001?partTypeName=Alternator&keywordInput=alternator (preferred)

More Information for REMY 20160

https://www.autozone.com/batteries-...tured-alternator-dl7014/333476_478360_0_24379


I attached a few pictures of the VR and Alternator I have in the car:

Thanks, Wolfgang

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Wolfgang,
NAPA shows a squareback housing. This will work with grounding the second brush. In theory these can have a slightly better output, but in reality it depends on the components inside and how close they fit etc. The listing says its rated for '35 amps'. Usually ratings are done to indicate maximum output (higher rpm).
So if 35 amps is near maximum, then this is not the right alternator for your car.

The alternator for your car ('69 w/ air conditioning) should be capable of producing 40 amps at 15 volts when the engine is at 1250 rpm.
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In 1969 Chrysler described or rated that alternator as a 46 amp alternator, and the standard one with v-8s as 37 amps.
see here: https://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1969/69_Barracuda0021.jpg
We don't know how they came up with the ratings but the method was probably consistant across the Chrysler product line.
The next two links look more promising. However I see in the reviews that some customers received alternators that don't look like the ones pictured.


Let me go find the last thread I recall about your car's electrics.
OK here: Burned bulk head connection

Maybe we can figure out what isn't working.
Maybe the first check once the battery is charged is whether the rotor is getting power.
With key in run, check the voltage at the positive field terminal.
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It should be the same voltage as the battery.
If not, then check for voltage at the regulator's input.

[Try not to leave the key in run very long ubless the engine is running.]

If there is power at the positive field terminal, then whether the alternator works at all can be checked by supplying the field with power.
An insulated jumper from the battery to the field terminal will work.
Make sure the conductor doesn't touch ground!
Easiest place to attach to the power circuit is probably at the alternator Batt terminal.
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A few other tests can be done with the wires disconnected. On the bench is easiest.
Checks
field circuit for short to ground.
field circuit for internal open. To do this , remove the ground brush, and touch probe to the slip ring.
Visual check of the brushes, terminals and insulators.

If its none of those, then its probably diodes or an open stator.

Looking back and one thing that puzzles me is why there is a terminal tab on the second brush?

A '65 housing should only have one insulated brush holder. The other should be cast in place.
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Mattax, thank you for the quick and extensive response. You gave me quite motivation and I did not wait until the battery is fully charged. So here the outcome of the steps you suggested, hope I followed them correctly and did everything right:

I. Battery (11.72V at the moment) connected and the ignition key on - reading around 11.60 at the Alternator field connector and around 11.55 at the VR input (the VR felt somehow warm) - differences in readings may also be user error or to be blamed on my cheap multimeter.

II. Removed brushes (they look good), and checked their connection, Alternator field does not have ground to the Alternator case

III. Cleaned the contacts on the Alternator and assembled it.

IV. Run a well-insulated wire from Alternator field to Alternator batt and mounted the Alternator back on the car - the green Alternator field wire is still connected

V. Started the car and went up to approx. 2000 RPM, Battery reading is 11.72V, Alternator output reads around 11.66 or so.

VI. Checked the Alternator gauge in the car - needle even with higher RPM slightly on the discharge side


I did the wiring on the Alternator very quickly and for sure it will not win a prize, but the connections are good.

I will order one of the two alternators, or if you guys can suggest a better one - I don't mind paying for an alternator, but I want something reliable and of good quality. My whole project was aiming towards cruiser with reliability.


Thanks, Wolfgang

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Mattax, I forgot to mention - I think the previous owner had the Alternator rebuild and upgraded to 65A. But I am not really familiar with the history of this Alternator.
 
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Battery (11.72V at the moment) connected and the ignition key for on - reading around 11.60 at the Alternator field connector and around 11.55 at the VR input (the VR felt somehow warm) - differences in readings may also be user error or to be blamed on my cheap multimeter.
So that seems to indicate the power is available to flow through the rotor.

Alternator field does not have ground to the Alternator case
The top one is grounded. Screw holds it directly to the case.
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V. Started the car and went up to approx. 2000 RPM, Battery reading is 11.72V, Alternator output reads around 11.66 or so.

VI. Checked the Alternator gauge in the car - needle even with higher RPM slightly on the discharge side

I agree, as best we can then its the alternator.

As you can see, with the roundback alternators, replacing the diodes, capacitor or stator requires soldering. Replacing the rotor requires a pulley puller - that's easy - and a press - easy only if you have one.
 
Since you are willing to take it apart, might as well try to figure out what is wrong. Then you can replace whatever is needed and you'll have a good backup.
That's the Royal You. LOL It might be someone you pay to replace the part.

A. Remove the ground brush. Measure resistance between the positive terminal to ground.
There should be no continuity. In other words, infinate resistance.

B. Stick the probe to the slip ring, or take the case apart and check for continuity between the slip rings.
upload_2020-7-8_22-59-15.png

There should be very little resistance in the rotor windings. If its open, its definately no good. Otherwise its a maybe. It could have two of the three windings open. That would still show coninuity on a meter but 2/3 of the electromagnetic would be dead.


Bench checking the stator and rectifier is more difficult.
If the multimeter has a diode tester you can try to check them.
The complication is they are soldered together in sets of 3 positive and three negative.
There is a special tester but hard to find...
That's all of the easy benchtop tests I can think of off the top of my head.
 
Thanks, I really appreciate it. Regarding A. and B. bench test, I did that. The two rings are not connected, no continuity between them. Did not check the rotor windings, but ordered a new alternator. Well, a back up Alternator is definitely on my list. Where can you get quality spare parts or is there someone how does good repairs? I am sure you are the man :). I would like to keep the original Alternator.

Thanks, Wolfgang

:thankyou:
 
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