Which alternator 60A or 46A?

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DartGTDan

DartGTDan

'71 Dart GT Fan
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My '71 Dart GT (318, auto, A/C) is in need of an alternator. NAPA shows a 60 AMP or a 46 AMP available. What was the factory alternator rated at?

The car has no extra electrical additions other than AutoMeter electric gauges (water temp, oil pressure & voltage) and a tachometer.

Thoughts?
 
Go with the higher amperage. At the lower level, the radio, lights, wipers used all at once can cause dim lights on the road. If you have a high energy ignition and/or car stereo amp, the problem gets even worse. At this level, 60 amps maybe marginal with all the extra load being used at once.

LOL! Remembering the old days when I had to turn the stereo off during a rain storm just to be able to see the road. Scary days....
 
DartGTDan said:
My '71 Dart GT (318, auto, A/C) is in need of an alternator. NAPA shows a 60 AMP or a 46 AMP available. What was the factory alternator rated at?

The car has no extra electrical additions other than AutoMeter electric gauges (water temp, oil pressure & voltage) and a tachometer.

Thoughts?
Click to expand...
My old man always said "Go big or go home".
It applies here.
 
DartGTDan said:
My '71 Dart GT (318, auto, A/C) is in need of an alternator. NAPA shows a 60 AMP or a 46 AMP available. What was the factory alternator rated at?

The car has no extra electrical additions other than AutoMeter electric gauges (water temp, oil pressure & voltage) and a tachometer.

Thoughts?
Click to expand...
The factory rating system and NAPA's supplier may or may not be using the same rating system.
Go to NAPA and put whatever they have on the counter. Bring a multimeter. Make sure the rotor is isolated from ground.

If there is a round back and a first generation squareback, the squareback may be a little more capable at idle speeds.
If its a revised squareback, I'd pass for one of the others.

PS. A real geniune Chrysler '60 amp' in '71 was, as best I can tell, similar to the Leece-Neville, and had special wiring and voltage regulator.
 
DartGTDan said:
is in need of an alternator.
Click to expand...
Do you know what's wrong with it?

And let me add here that in most cases you're best off not trading it in as a core.
So if you need to do a quick swap, fine. But odds are the new one will have a crappy wrong pulley, and be missing the internal grease shield.

Bigger is not always better, especially when the battery is run down. Assuming thats the situation now since you say a new alternator is needed, put the battery on a charger.
 
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That’s true. If the battery is shot, a new one is needed before a stock or more powerful Alt. is used.
 
This now has me questioning the delco squareback 60A I got from rockauto awhile back that's set up with a single field wire. Other looks to be a case ground. I picked up a solid state VR that looks like the ole black box type. Says thats rated for up to 65A. I guess I will find out.
 
I WOULD NOT put a high output alternator on a car that has the factory ammeter wiring. WOULD NOT

Read this article. Even if you don't follow this "cure" the article gives the what and why of the problem.

"Ma" knew this. If you bought a factory car 'back in the day" with an optional 65A alternator, there was DIFFERENT MODIFIED wiring used, which has become known as "police/ fleet/ taxi" wiring.

Catalog
 
I dont intend to. Going to bypass ammeter, convert it to volts, and run alternator output to battery bypassing the bulkhead. Pic# 2 is what I will be doing

amp-ga18.jpg


Screenshot_20200604-112856_Gallery.jpg
 
DartGTDan said:
My '71 Dart GT (318, auto, A/C) is in need of an alternator. NAPA shows a 60 AMP or a 46 AMP available. What was the factory alternator rated at?

The car has no extra electrical additions other than AutoMeter electric gauges (water temp, oil pressure & voltage) and a tachometer.

Thoughts?
Click to expand...
May be a good time to up grade to a one wire alternator.
I put a Power Master 90 amp on my 340 and never looked back, it performs very well.
My car no longer has any factory wiring and does not support a factory ammeter.
Single wire is just that, one wire direct to the positive battery terminal.
Job over
 
rumblefish360 said:
What was the MOD?
Click to expand...

You askin me Rumble? It's documented in some of the service manuals. One of the ammeter wire was dead-ended, and larger wire was run through the firewall using individual grommets. Used on factory 65A optional alternators. Even back to ?? not sure ?? 72 ish the big boats like fury used the external shunt ammeter
 
Yes sir! I was askin. Do you have a diagram of the shunt set up?
 
Hit me up. I might have one? Or I could show you how to rebuild yours. You know the quality of my work.
 
rumblefish360 said:
Yes sir! I was askin. Do you have a diagram of the shunt set up?
Click to expand...
You can look it up in one of the shop manuals at MyMopar. I'm pretty sure that something like a 72 C body is external shunt. You can tell immediately by the size of the ammeter wires. Everybody who did this, GM, Ford, Mopar, used the harness as a shunt. The fords were particularly "numb." On my Rangers I've had you had to STARE at the ammeter while turning on the lights/ engine off, to see if it moved at all I actually thought about trying to implement this, until I found the "ammeter to voltmeter" old thread on here. If I were younger I might play with "this" some more
 
from 1970 Dart factory service manual:
slant six - 26 =/-3 amps
standard all other models - 34.5=/-3
heavy duty or Air Conditioning - 44.5=/-3
special equipment (fleet) - 51=/-3\

The fleet 51=/-3 amp alternator was mostly for police/emergency services vehicles and taxis - WHEN USED THE FACTORY BYPASSES THE BULKHEAD CONNECTOR AND RUNS THE MAIN WIRES (BLACK AND RED) THROUGH A GROMETTED HOLE DRILLED IN THE FIREWALL

Given this info it sounds like the 46 amp is the way to go if you are using factory wiring. I tried to use a 100 amp alternator and managed to fry the wires under the dash of my 70 Dart Custom. If you use the 60 amp unit I'd at least bypass the bulkhead connector. If you don't have a lot of added power demanding stuff, you shouldn't need more than 46 amps.
 
str12-340 said:
from 1970 Dart factory service manual:
slant six - 26 =/-3 amps
standard all other models - 34.5=/-3
heavy duty or Air Conditioning - 44.5=/-3
special equipment (fleet) - 51=/-3\
Click to expand...
These are the test amperes, which are usually, but not always, lower than the 'rating' amps for the same alternator.

str12-340 said:
The fleet 51=/-3 amp alternator was mostly for police/emergency services vehicles and taxis - WHEN USED THE FACTORY BYPASSES THE BULKHEAD CONNECTOR AND RUNS THE MAIN WIRES (BLACK AND RED) THROUGH A GROMETTED HOLE DRILLED IN THE FIREWALL
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Correct. We've posted these diagrams a number of times.
It's interesting to note that the assembly drawings for 1967-69 A-bodies illustrate the installation of the 60 and 65 special alternators. They are only listed under Fleet sales although I'm not aware of any surving examples on compacts until much later. Like on this'74.
Special Equipment alternators those years were rated 60 amp Chrsyler, and 65 amp Leece-Neville.

The later rear window defrost grid cars also came with a '60 amp' alternator. In this case it may have been a regular squareback. Still need to find an intact survivor to verify that. This option has a slightly different wiring to handle the load to the defroster. Pictures and diagrams here How rare is electric rear defrost?
 
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Stay with a stock original one. Or you could put a Chevy one in it and start some Frankenstein kinda project? Grafting on other parts from other cars. Lol.
 
Years ago I did the ammeter bypass, added a 2nd parallel path heavy gauge wire (with a fuse link) from the alternator stud to the starter relay's battery stud, put the headlamps on relays, etc...

Recently, I drove the car to work and everything was fine. Then, after work the volt gauge was sitting at just over 10V. Raising the rpms did not increase the voltage.

All of my connections are clean and tight (I like to use dielectric grease). After lots of measuring/testing (using my battery and my buddy's known good battery) I believe the alternator is toast. I performed the "full field" test (at idle and at higher rpms) and neither battery showed a voltage increase.

Has anyone seen or tried this on a non-adjustable voltage regulator?

 
DartGTDan said:
Years ago I did the ammeter bypass, added a 2nd parallel path heavy gauge wire (with a fuse link) from the alternator stud to the starter relay's battery stud, put the headlamps on relays, etc...

Recently, I drove the car to work and everything was fine. Then, after work the volt gauge was sitting at just over 10V. Raising the rpms did not increase the voltage.

All of my connections are clean and tight (I like to use dielectric grease). After lots of measuring/testing (using my battery and my buddy's known good battery) I believe the alternator is toast. I performed the "full field" test (at idle and at higher rpms) and neither battery showed a voltage increase.

Has anyone seen or tried this on a non-adjustable voltage regulator?

Click to expand...

deja vu all over again.
That video is specific to that company's adjustible regulator.
 
DartGTDan said:
Years ago I did the ammeter bypass, added a 2nd parallel path heavy gauge wire (with a fuse link) from the alternator stud to the starter relay's battery stud, put the headlamps on relays, etc...

Recently, I drove the car to work and everything was fine. Then, after work the volt gauge was sitting at just over 10V. Raising the rpms did not increase the voltage.

]
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Must be something in the air around here. Took the car out to breakfast this morning and had the same thing happen. Haven’t dug into it yet. Last time something like this happened the insulating washer on the alt’s battery terminal had disintegrated and shorted out the charge wire( I have a 100 amp breaker inline)so I was running off the battery til it went dead.
 
DartGTDan said:
My '71 Dart GT (318, auto, A/C) is in need of an alternator. NAPA shows a 60 AMP or a 46 AMP available. What was the factory alternator rated at?

The car has no extra electrical additions other than AutoMeter electric gauges (water temp, oil pressure & voltage) and a tachometer.

Thoughts?
Click to expand...
I have a use chrome square back 60amp I would let go $ cheap if you need it.
 
I'll make my pitch here for ammeters. IMHO if all you have is a volt gauge then you are missing a key piece of diagnostic equipment on your dash. If the alternator fails or the voltage regulator starts to go, you often have advanced warning on your ammeter in the form of inappropriate charge/discharge or erratic readings, whereas your volt gauge only informs you that the system has failed and you hope you are lucky enough to make it home or the parts store. The parallel, though even worse is the oil warning light as opposed to an oil pressure gauge.

Yes there are weaknesses with the original systems (especially when they are 50 plus years old). My solution is to use a modern ammeter in a gauge cluster under the dash, and to replace and maintain wiring long past it's expiration date.
 
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