Only 12.31 volts

[drbrick]

Nice diagram Rob.I see what you are getting at.
Thanks

 

[drbrick]

No, there is no +,-. However the two field terminals in reality are just one very very long piece of wire wrapped around the armature, but insulated from it electrically.

Make sure both wires are disconnected from the field terminals, ohm's check the two field terminals together as I mentioned and then double check that, with one ohmmeter lead connected to one of the field terminals you have no continuity to the outter case! Infinate resistance is what you are looking for as far as grounding out to the case.

Well sir-0.0 ohms @ 1 FLD connection to alt case,and 3.4 ohms on the other FLD connection to alt case.
So something in the alt is fried-yes?
If so-why would the alternator still be putting out higher voltage than the battery has?
Making progress though.
I have an old alternator that i tested with the ohm meter,and it shows that the ohms are OL. I think i may slap that one on real quick and give it a whirl.
Making progress i think.

 

[Gryzynx]

Well sir-0.0 ohms @ 1 FLD connection to alt case,and 3.4 ohms on the other FLD connection to alt case.
So something in the alt is fried-yes?
If so-why would the alternator still be putting out higher voltage than the battery has?
Making progress though.
I have an old alternator that i tested with the ohm meter,and it shows that the ohms are OL. I think i may slap that one on real quick and give it a whirl.
Making progress i think.

You answered your own question here;

So something in the alt is fried-yes? NO!
If so-why would the alternator still be putting out higher voltage than the battery has? Because the alternator itself works. Your problem is with the voltage regulator and/or your regulator wiring.


Now, you proved the alternator works when you tapped the ignition feed onto the 2nd field terminal and the alternator started to charge. You also proved you do not have the 2 field alternator when you checked the resistance and found 0 ohms to the case from the 1 FLD terminal. Now, what you have to do is get an alternator and regulator matched to each other. '69 and earlier applications use the 1 field wire, but the wiring in the link I sent as well as all discussion here refers to the 2 wire connection. The difference between the 2 wire field and the single wire field is obvious when you look at the resistance to case reading. The 2 wire will read open, (OL on your digital meter), and the single wire will read a few ohms on one field terminal and 0 ohms on the other to the case. I don't know what to think about that 3 wire regulator you have. I'd suggest trashing everything and getting an alternator and regulator from the same car or truck along with the proper wiring harness. If you take a full engine harness, unwrap the tape and salvage everything from the alternator to the regulator, without cutting it up. Once you have this in hand, compare it to the wiring diagram on the conversion page and everything should start to make sense. Might also be an opportunity to add electronic ignition as well.

 

[drbrick]

You guys aint going to believe this!The old alternator works just fine!New alternator does not work!
What started this whole mess was the batt not charging-right?So i took the old alt in and had it tested-Right?Dude behind the counter tests it-tells me its no good-Right?
So i buy a new one-guess what,it dont work.Well It might have worked once,but the wires going to and from the alt were wired all wrong,so maybe that fried the alternator?
But why did it not fry the old alternator?Dont know..
Bottom line is old alternator is now wired up by the diagrams you gentlemen provided me,
and engine idling i now have 14.2v,and at half throttle it is at 14.4.
Now if the car dont burn down because of some other wiring issue.....
Any way-I would not have gotten this thing fixed with out the help of you guys.If you are ever in Nor cal-you are coming over for beer and brats!
Thanks so much Rob and Nothingbutdarts.You guys rock!:notworth:

 

[nothingbutdarts]

You guys aint going to believe this!The old alternator works just fine!New alternator does not work!
What started this whole mess was the batt not charging-right?So i took the old alt in and had it tested-Right?Dude behind the counter tests it-tells me its no good-Right?
So i buy a new one-guess what,it dont work.Well It might have worked once,but the wires going to and from the alt were wired all wrong,so maybe that fried the alternator?
But why did it not fry the old alternator?Dont know..
Bottom line is old alternator is now wired up by the diagrams you gentlemen provided me,
and engine idling i now have 14.2v,and at half throttle it is at 14.4.
Now if the car dont burn down because of some other wiring issue.....
Any way-I would not have gotten this thing fixed with out the help of you guys.If you are ever in Nor cal-you are coming over for beer and brats!
Thanks so much Rob and Nothingbutdarts.You guys rock!:notworth:

You answered you own question when you said you had 0.0 ohms from one field terminal to case (0.0 ohms means you have a solid connection to the case) It should read OL or infinate like the meter leads aren't touching anything. The other field terminal had 3.4 ohms. NEITHER feild terminals should have ANY ohms (or continunity) to the case. However if you check ohms from one field terminal to the other you will get somewhere arouind 50 ohms to 150 ohms.

Congratulations!

 

[nothingbutdarts]

OK, voltage drops with the engine running means it's not charging at all. Voltage should go up 1 to 2 volts with the engine running dependant on engine speed. Do you have any indication on your ammeter? If no, or discharge, you just confirmed what I said.

360 engine, or ballast resistor voltage does not have any effect here. Did you keep the 69 318 alternator, or did you use the alternator that came with the 360? If you replaced the alternator, did you specify the 69 318 version, or did you go with the 360 and model/year of the donor. Big difference in voltage regulators here and they are not compatible. Also check that your alternator output is making it back to the battery. Problems here can be the ammeter, or the firewall connectors.
check for +12V at the heavy red wire at the alternator with the engine not running. (It should be present). Make sure the important engine to firewall ground strap is intact.

Try this troubleshooting guide;

http://www.mymopar.com/index.php?pid=78

Here's a wiring diagram for your car;

http://www.mymopar.com/downloads/1969/69BarracudaA.jpg
http://www.mymopar.com/downloads/1969/69BarracudaB.jpg

Gryzynz,

I looked at the link @My Mopar. It's very good information however: In my factory service manual for 1979 there is no reference to the 'Field terminal +" or "Field terninal -" I as well don't see it stamped in the case anywhere. I don't believe it matters which field wire you hook on which field terminal. Just my .02. All you have is an insulated winding of wire around the rotor that's connected to the slip rings on the back of the rotor shaft. The amount of current/voltage you apply to the field increases the electro magnetic field it puts out which increases or decreases the output of the alternator.

 

[Gryzynx]

I think you are right about those field windings. After all, an alternator produces 3PH AC, which is rectified into DC by the 6 diodes. Polarity of the output post is determined by the arrangement of the diodes, (typically + to post, - to frame). Field winding is simply a coil of wire and polarity will make no difference as long as it has continuity and current is flowing. The original 1 wire field alternator used with the mechanical regulator has some sort of inherent polarity because one side of the field winding is connected to the alternator case which, in a typical vehicle, is negative, therefore the other field terminal would need to be positive. Likely the nomenclature was carried over to the 2 wire field alternator. For the purpose of the article, it does seem to be necessary to identify the terminals.

I see there are a couple other threads starting about alternator testing and electronic vs. mechanical regulators. Mabye the mods should consider a sticky?

 

[Gryzynx]

No no no... you still need the main feed to go inside the car for power for all the interior and lights (that will be the old wiring). Basically you end up with two routes, one that goes through the bulkhead, inside for your accessories (including gauges, radio, lights, etc.) and then the new loop that bypasses the interior and goes straight to the battery for charging. They both end up at the starter relay. You just relieved having ALL the power having to go through the bulkhead.

See the diagram I modified.. the red wire from the alternator is that "new" wire. Make sense?

Should note this will bypass the ammeter, it will no longer indicate charge or discharge.

 

[drbrick]

Cleaned up the wiring a bit,and added a fusible link to the extra primary wire as suggested.And it still works!
Thanks again to all who contributed to this thread,and for helping me along the way!!!

 

[nothingbutdarts]

It looks really good. I'm glad you can go out & enjoy it!

 

[skykeith]

If you have a 2 field terminal alternator and it reads approx. 4 ohms on one terminal and 0 on the other to the case, then someone has probably left off the insulating washer that isolates the brush from ground. Install that washer and you probably have a good alternator.