1971 Slant-six ballast resistor ID

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Good idea. I will check my alternator tomorrow...
:thankyou:

My 2-prong regulator :
Voltage regulator.jpg

To match, my alternator must be of isolated-field type.

alternator types.JPG
 
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If you want to figure out what each blue wire connects to, without unwraping the harness tape, make continuity checks on each one.
In other words remove them from the resistor and each other. Then check each for connection to the alternator field, regulator, and any smog era devices such as choke assist if they are present.

My guess is that one wire is the J2 from the key switch Ignition Run. It should have a white tracer on it according to the book.
And the other leads to a splice or a junction at one of the other terminals.
Something like this
upload_2020-12-23_16-16-58.png


or this
upload_2020-12-23_16-22-20.png
 
Good morning buddies..

My alternator is Chrysler made, but has been replaced by a precedent owner.
It's a more recent squaredback type.
IMG_20201224_112728.jpg

So, two field terminals.

... and connected like that :
upload_2020-12-23_10-21-23-png.png

And J2C wire (connected to the alternator field) is dark blue with a white tracer.
No white tracer on other J2x wires.
The junction of J2 and J2B dark blue wires is located onto the ballast resistor connector.
So, now, just have to restore the connectors and relocate the ballast resistor onto the firewall.

Thank you all for your efforts, you are the best...
:thankyou:
François
 
So, now, just have to restore the connectors and relocate the ballast resistor onto the firewall.
I don't have any suggestions for the firewall repair. From the photo - this car is beautiful and deserves a nice looking repair.

An advantage of the original mounting location will be the additional protection against rain or snow when the hood is opened.

For the terminals, if you want to restore to original.
The closest commerically available is a Series 58 made by Packard Electric, sometimes listed under Delphi or Aptiv.
Female terminal 2965471 is brass and 1201601 is tin plated brass specifically designed for two 14 or 16 gage wires.
A terminal for one 14 ga wire will also work. Just make sure the wires are side by side so the conductors for each get crimped properly.

This is the original from a 1967.
upload_2020-12-24_9-20-0.png


upload_2020-12-24_9-22-5.png

More pictures in this post

The original plastic insulators should work with the 58 style.
However be aware that plastic insulators made for Packard 56 series female terminals may or may not fit.
That happened to me.
Exterior differences are subtle
upload_2020-12-24_9-16-47.png


More pictures in this post

The 56 series is more common and you may find that is more practical to just use 56 terminals and housing.
Seen that on some reproduction harnesses. It would take a real expert to know the difference.
upload_2020-12-24_9-26-11.png


The above crimp isn't great - the conductors should extend out from the crimp.

The one below was even worse
upload_2020-12-24_9-24-22.png
 
For the firewall, as the hole has been damaged, I will use an threaded insert that will be invisible under the ballast resistor.

Here in Europe, finding the 56 or 58 type terminals is easy, but the rectangular black plastic insulators...no.
I spent my afternoon searching but invariably, I was redirected to american websites which ask for abusive shipping fees (something like $25.00 or more for 5 insulators, when they accept to ship internationally and it's not always the case) :realcrazy:
Finally, I found "theelectricaldepot.com" and ordered a pack of 10 serie 56 insulators + 25 serie 56 terminals + international shipping for $19.00
At last, a decent price

56 serie insulator.JPG
56 serie terminal.JPG


I really appreciate your help, Mattax and my Demon sincerely thanks you... :thumbsup:

Merry Xmas
François
 
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Today, I placed an aluminium insert into the firewall.

Ballast resistor.jpg


Insert.jpg


And the ballast resistor is back in its original location.
Ballast resistor (2).jpg


Now, I'm waiting for the rectangular terminals from the electrical depot...
 
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Didn't the original ballast resistor use spade lugs, not screw lugs?
If so, the res is not original & could be other than the original 0.5 ohm.
 
Pretty sure mother Mopar did not use AC or Delco [ GM parentage] electrical parts in their cars. They used Motorola & Autolite. Companies like Mallory made ign systems & ballast resistors & the resistance of the BR needs to be correct for the coil it is used with.
 
I don't know if it's the correct ballast resistor but I have had this Demon for several months and it starts/runs perfectly.
I will test it with an ohmmeter.
 
I tested my resistor today and I found 1.2/1.3 Ω
So, it's not the good one.
I will replace it by a 2095501 original Chrysler resistor (0.5/0.6 Ω)

About the connectors, I found this picture on internet :
Demon verte.JPG

And the owner claims that its Dart has only 10k miles. So, I suppose that the connectors are original.
 
Check the zero on your meter and probes. Rezero or subtract that number. ;)
Also note the temperature. '71 Plymouth FSM says 0.5- 0.6 Ohms at 70 to 80 deg F.
If its still far off the spec, then look for a correct replacement.
 
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