1974 Duster slant w/ac. Did this come with a 60amp Alternator? Or, could it have been stronger from the factory being that I have a/c ect. It might have a light package because it has the map light ect.
Alternator?
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According to the dealer sales book, '50 amp' was standard with A/C, and '65 amp' was standard with electric window defroster grid.
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The 1970 Hamtramck Registry - 1974 Plymouth Dealership Data Book - Valiant/Duster
If it came with rear defrost and 65 amp alternator, it would also have been equiped with the matching wire harness. So these things would be pretty obvious. A guy posted some photos of a rear window defroster and harness from a '73 within the past year.
p. 16
The 1970 Hamtramck Registry - 1974 Plymouth Dealership Data Book - Valiant/Duster
If it came with rear defrost and 65 amp alternator, it would also have been equiped with the matching wire harness. So these things would be pretty obvious. A guy posted some photos of a rear window defroster and harness from a '73 within the past year.
Mattax, there is a 50amp green tag on my Alternator, so your right. Do you think I can switch to a 60 amp with my factory wiring? I do have a small stereo amp connected to my Battery. Don't want to change any factory wiring though
Geez! If the car still has the original alternator, that's probably the most reliable one available!
Anything new or from a rebuilder these days is a crapshoot.
At some point, check the brushes and check for play in the bearings.
How many amps maximum can the stereo draw? and how many amps are you actually using?
Get the first from the stereo or amplifier. It will be on the label and the instructions, etc.
To know how many amps it draws when you are playing it, you can check it with the car's ammeter.
a. After starting the car, drive around with the stero off until the ammeter shows the battery has finished charging.
b. Then turn the stereo on to the typical volume you use. Observe how far the ammeter deflects from zero toward charge.
If you hardly see it move, then its drawing just a couple amps and nothing to be concerned about.
If it shows 5 or more amps, then its worth thinking about some minor modifications to the wiring.
(The ammeter scale 40 amps to 40 amps, zero in the center. )
Car being put back together, so what do you guys think. Is a 60 amp safe on my 74 Duster w/ A/C light package, 80's stereo with small amp, factory electronic ignition. Don't want to touch any factory wiring. It came with a 50amp
Honestly I don't know why you would change alternators if the factory one is still in good condition.
If you want to have a replacement one on hand, OK. Although a replacement isn't so rare that a parts store can't get one in that day, at most within two or three.
Since things are apart right now, you can do some basic checks of the alternator on the bench. Then when everything is together, you can check the stereo draw - but you're saying its pretty small unit.
One problem with replacement vs. factory is they aren't measured and rated the same way.
The only way to know the tuth about max output will be if/when someone tests an original at different rpms and loads.
That is also true for any 'replacement' unit, and we could measure it holding the same voltage as the factory unit tested.
Occassionaly a test sheet will show up in the box with a replacement unit. I think this was the general practice of a particular big rebuilder maybe 10-20 years ago. These things sit on the shelf in a warehouse so once in a while show up.
Here is themax output plot from the only mopar one I've seen.
This is was in box with '78amp' revised squareback.
The rpm is Alternator rpm, not crank rpm.
Notice at the top it says the test was done at 13.2 Volts.
The factory service manual test is done at 15 Volts.
If this replacement alternator had been tested at 15 Volts, the Amps out at all rpms would probably be less.
But the main point is that the 'rating' doesn't tell us alot unless we were comparing all from the same manufacturer.
A few years ago A/C Delco or delco-remy had output graphs for some of their GM alternators. Notice that sometimes a higher rated alternator has worse performance at low rpm.
We don't have this type of info for the Chrysler roundbacks and squarebacks alternators so its all a big maybe when we buy replacement. On top of this, we can't be sure the parts between different alternators weren't mixed, or that any new parts installed had any sort of quality control.
If you want to have a replacement one on hand, OK. Although a replacement isn't so rare that a parts store can't get one in that day, at most within two or three.
Since things are apart right now, you can do some basic checks of the alternator on the bench. Then when everything is together, you can check the stereo draw - but you're saying its pretty small unit.
One problem with replacement vs. factory is they aren't measured and rated the same way.
The only way to know the tuth about max output will be if/when someone tests an original at different rpms and loads.
That is also true for any 'replacement' unit, and we could measure it holding the same voltage as the factory unit tested.
Occassionaly a test sheet will show up in the box with a replacement unit. I think this was the general practice of a particular big rebuilder maybe 10-20 years ago. These things sit on the shelf in a warehouse so once in a while show up.
Here is themax output plot from the only mopar one I've seen.
This is was in box with '78amp' revised squareback.
The rpm is Alternator rpm, not crank rpm.
Notice at the top it says the test was done at 13.2 Volts.
The factory service manual test is done at 15 Volts.
If this replacement alternator had been tested at 15 Volts, the Amps out at all rpms would probably be less.
But the main point is that the 'rating' doesn't tell us alot unless we were comparing all from the same manufacturer.
A few years ago A/C Delco or delco-remy had output graphs for some of their GM alternators. Notice that sometimes a higher rated alternator has worse performance at low rpm.
We don't have this type of info for the Chrysler roundbacks and squarebacks alternators so its all a big maybe when we buy replacement. On top of this, we can't be sure the parts between different alternators weren't mixed, or that any new parts installed had any sort of quality control.
Check for shorts beween output and housing (ground), and input (field) and housing.
Check for open field circuit. (continuity between fiueld terminals).
Carefully remove the brushes. Check for wear, and any damage to the insulators and insulating washers. Replace any if needed.
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