I know, i know, its been answered before. But there have been several different answers to the same wonderful question. But the question is: what is a good, not too terribly expensive replacement for my aging alternator?

I've read that NipponDenso makes a good replacement, but I've also read that Chrysler's 120 amp is good as well.

Reason I ask: I've been having some problems with the car at idle with the headlights on, sometimes it stalls out, so i figured I'd give all the connections a good looking over, cleaning and retightening as necessary, but I'd also like to upgrade as well. It'd be nice for my headlights to not dim when I'm not moving.

Hmmm, when I'm cleaning the connections, would the application of some di-electric(?) grease be worthwhile, or am i talking out my bum again?

Another question: if I purchase an alternator that is internally regulated to I have to remove the Electronic regulator that's already there, or can i leave that as it is?

Hmmm, I'm sure I've forgotten something, but sleep deprivation will do that.

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The old white brick

You can with reasonable ease install any of the '89-up RWD Mopar 40/90A alternators (the rating means 40A max at idle, 90A max overall). These were made by Chrysler, Bosch and Nippondenso. All of them are about equally good in terms of performance and reliability. The Nippondenso is the smallest and lightest, therefore easiest to adapt. The Chrysler is the largest and heaviest, therefore the hardest to adapt. All of them fit the same bracket, but none of them will fit correctly on your stock '71 brackets without bracket modification. Or, you can use the 2-piece stamped steel bottom bracket from a late-'70s F-body with slant-6, and the upper slider bracket from an '89 M-body (Diplomat ,Gran Fury, Fifth Avenue) with 318. Can probably also get away cheaper and easier with one of those universal chrome curved upper slider brackets.

Any of these alternators will hook up just the same as your present alternator, only difference being that the newer alternators use small-diameter threaded studs for the two field connections, instead of 1/4" blade terminals. Not hard to work around.

But, really, a properly-working original-type alternator won't exhibit the problems you mention, either.

Internally-regulated? I don't like this yucky GM idea. Lose a voltage regulator, and you're screwed until you can find time to pull the alternator all apart OR swap the whole alternator. I'll take my voltage regulators bolted to the firewall where God intended, thank you.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thank you Dan, most informative as always. Time to go look in Car-part and see what's available for the picking.

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The old white brick

Internal regulared, nope. My 89 Diplomat had the 50-120 alternator
(looks identical to the 40/90 with a higher rating. Still had typical VR on firewall. Cummins powered trucks used this setup til at least 97. This alt was also used on many mid 80s FWD cars except RWDs had a double V belt pulley and the wrong wheel drives had serpentine. The one on my Dip went bad and I got a replacement from a Turbo LeBaron and only had to swap pulleys. Bolt on, takes a 15/16" socket and an impact. These were regulated in the computer on the wrong wheel drives and the Dakotas too, NOT internally in the alt.

Whee, even more choices, its like an addition to the candy store.

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The old white brick

If you put in a 50/120A unit, bypass the ammeter.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Okay, too much for the meter? or the wiring?

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The old white brick

Yes. (Both)

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

If I put a 75 amp unit in my car which currently has a 60 amp unit (I think, is it wrote on the alternator somewhere?), will I have any ammeter troubles?

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

You'll never have ammeter trouble with any alternator under normal circumstances. It's abnormal circumstances you have to watch out for, when that alternator starts crankin' out more amps than the ammeter was designed to handle. Let your battery die, get a jump start, and immediately your alternator will crank out max amps, burying the ammeter needle on the right and easily overloading the A1A main feed wires and the ammeter itself. Extensive damage is possible.

You probably won't have too much risk of trouble with a 75A unit.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Okay, so how much should i be looking to pay for a junkyard piece through Car-part? Or should I look for a new replacement? I've seen them on carpart for as little as $50. Good deal?

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The old white brick

Kind of depends on exactly what it is that you want. Once you nail that down, it gets easier to make recommendations for sources and pricing advice.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

...is for my car to not stall out during morning commute, which is all of 20 minutes. As for parts. Would a 40/90A unit for a diplomat be correct? When i searched on Car-part for it, it showed alternatives. Maybe I'm just too tired to think straight at this point. Let me know if my muddled brain is correct and I check in the morning.


PS. I didn't know you couldn't add HTML code to subject lines.

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The old white brick

Mmm. Usually paying attention to the alternator won't fix that. Stalling is generally addressed by paying attention to the fuel and ignition systems.
Sure, that'll work, but the results don't differentiate among the Bosch, Nippondenso and Chrysler units. (Try 1989 Dodge Truck D150 instead). Prices look kinda high...you may want to look to eBay instead. That way you get to see the alternator you're thinking of buying.

I'mmmm.....pretty sure you can't. Maybe you can. H'm...

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

You can get a "stock" Mopar alternator all the way from 37 amps to 78 amps, in the same case, no bracket swaps needed. Most newer ones that use this alt (mid '80s) were either a 65 or a 78 amp. You know, the normal Mopar alternator that they used forever that weve all seen a million of....