Another alternator problem

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Craig Burriss

Craig Burriss

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Hey guys, some of you may remember a month or so ago my one wire power master alternator was draining the battery on my 70 Duster so I sent it in for repairs, they sent it back and it was working fine until the other day.
It doesn’t drain the battery now but it doesn’t charge it either. It actually puts out 0 voltage.
Even though it’s directly up against the bare metal cylinder head, I thought it may have been a ground issue like everything else on my car, so I took a jumper cable and grounded the case directly to the battery ground.
It’s a one wire alternator with a 10 gauge wire going from the output stud of the alt to the power stud on the starter relay over by the battery. I emailed them a couple of weeks ago and they never responded. Am I forgetting something?
(Yes I put the belt back on when testing it lol)
274C2A4D-AEB5-4B3F-82B9-A2DB9163ED9B.jpeg


Thanks guys.
Merry Christmas and happy New Year
 
One wire is pretty simple. IF it is actually hooked to the battery and IF it is getting spun fast enough it should charge. otherwise, something wrong internally

So double triple check belt tension

Put a meter on the output stud. If it won't "come up" rev it up smartly and see if the output comes up to 14-15V. or more then you have an open between the output terminal and the battery

I'm not familiar with these. Is this the one with the little rectangular VR bolted to the outside? If so make sure it is tight, and has not been damaged.
 
Make sure it is not now spinning backwards. If you spin them in reverse they pop the diodes and then thy suck the battery dry. But worse is everything runs in reverse polarity Most of the equipment is resistant to this abuse, but not the radio. You can tell right away when this has happened because your clock will be running backwards, and all the music sounds freaky in reverse. Don't panic. This effect only lasts as long as it took to read this far.
Merry Christmas
 
67Dart273 said:
One wire is pretty simple. IF it is actually hooked to the battery and IF it is getting spun fast enough it should charge. otherwise, something wrong internally

So double triple check belt tension

Put a meter on the output stud. If it won't "come up" rev it up smartly and see if the output comes up to 14-15V. or more then you have an open between the output terminal and the battery

I'm not familiar with these. Is this the one with the little rectangular VR bolted to the outside? If so make sure it is tight, and has not been damaged.
Click to expand...
I had the multi meter on the output stud at varying rpm but nothing showed.
Here’s what it looks like. I don’t think anything is loose on it but I’ll check next time I have a chance.
EA38679B-0460-40A1-BB2B-55555EF1FEAD.jpeg
 
AJ/FormS said:
Make sure it is not now spinning backwards. If you spin them in reverse they pop the diodes and then thy suck the battery dry. But worse is everything runs in reverse polarity Most of the equipment is resistant to this abuse, but not the radio. You can tell right away when this has happened because your clock will be running backwards, and all the music sounds freaky in reverse. Don't panic. This effect only lasts as long as it took to read this far.
Merry Christmas
Click to expand...

For just a second there I thought "Shirley, you are not serious". But then...........

 
AJ/FormS said:
Make sure it is not now spinning backwards. If you spin them in reverse they pop the diodes and then thy suck the battery dry. But worse is everything runs in reverse polarity Most of the equipment is resistant to this abuse, but not the radio. You can tell right away when this has happened because your clock will be running backwards, and all the music sounds freaky in reverse. Don't panic. This effect only lasts as long as it took to read this far.
Merry Christmas
Click to expand...
So that’s how flux capacitors work
 
Nothing is loose in or on the alternator. I put it back on the car and tested it again to see if something changed somehow.
When the car is at idle and my multimeter is hooked to the output stud of the alternator, the voltage sits at about 11.87 volts and slowly drops about .01 volt every 10 seconds. At about 4Krpm the voltage slowly rises about .01 volt every second.
I’m going to call Powermaster when they open back up tomorrow.
 
I called them and the tech guy said they dyno test everything before they ship it out and said to check the grounds and raise the rpm some. I did all of that for a third time and still no change, so I sent it back in to them with a note explaining it’s issue. Let’s hope it works when it gets back. I’ve had this car for 3.5 years and have only driven it about a mile. This alternator is the only thing holding it back now so this is really frustrating.
So far PowerMaster has been very understanding of everything and I am not blaming them at all.
 
Does the green wire on the back run to ground? I'm of no use electrically or much else for that matter.
I wonder if it's another issue faulting out your alternator?
 
4spdragtop said:
Does the green wire on the back run to ground? I'm of no use electrically or much else for that matter.
I wonder if it's another issue faulting out your alternator?
Click to expand...
That wire is attached to one of the brushes and goes down into the alternator guts
 
Unfortunately, the design of those stock style case alternators whether they are OEM or aftermarket is total garbage.

You will be a lot better served by converting to a Delco or Denso style alternator. Not sure what works well on a big block for fitment, but I 12SI alternator swapped my Duster, just a basic parts store one in 2011 and it has been flawless. I always had trouble with the Mopar alternators and regulators. If I was on the road and had a failure I would be able to grab one anywhere for under $100.
 
goldduster318 said:
Unfortunately, the design of those stock style case alternators whether they are OEM or aftermarket is total garbage.

You will be a lot better served by converting to a Delco or Denso style alternator. Not sure what works well on a big block for fitment, but I 12SI alternator swapped my Duster, just a basic parts store one in 2011 and it has been flawless. I always had trouble with the Mopar alternators and regulators. If I was on the road and had a failure I would be able to grab one anywhere for under $100.
Click to expand...

On the other hand there's been millions of those on cars and trucks that went untold miles. I agree, there are better designs, which has nothing to do with the current problem
 
67Dart273 said:
On the other hand there's been millions of those on cars and trucks that went untold miles. I agree, there are better designs, which has nothing to do with the current problem
Click to expand...

I wouldn't be surprised if even powermaster uses old cases from rebuilders, and questionable reman parts on this model in any way. Considering it's a re-occurring problem, going a different direction might be just the ticket. Everyone I know personally that had the original style alternators that weren't actually OEM has had an issue. I just have doubts about component quality because I'm sure powermaster has to buy from suppliers like anyone else. Compound that with the one wire system addon and you're probably at a loss for field troubleshooting, unless you can put 12V on one side and ground the other to full field like an OE design.

My friend got his 71 Demon on the road, the OE alternator didn't last long after sitting for so long, and the reman didn't make 3 months. Slung a 12SI on there and it's been 3 years already where it's flawless. I personally went through 2 mopar alternators, one aftermarket regulator, and one mopar regulator in about a 6 year span. I'd rather fix my car once and be done with it, but that's my two cents.
 
Maybe the odds are better or maybe you have just been lucky. I've been through a few 12SI in my wagoneer. Feb 2019 made the last hour and a half back into town on battery alone thanks to the junk output stud insulator and lack of QC - from a AC Delco with GM numbers on the box. All rebuilds, remans, etc are a crap shoot.
Years ago I rarely used electrical stuff from a junkyard. Now, if its original and in OK condition, its my first choice.
shake_head-gif.gif


Here's the insulator. That's not loose! Junk.
upload_2020-1-7_20-8-0.png


upload_2020-1-7_20-16-12.png


This was exchanged for an older AC Delco 'rebuild' which did not have that issue. Yes I opened up and checked it out. Had to clock it anyway.
 
Mattax said:
Maybe the odds are better or maybe you have just been lucky. I've been through a few 12SI in my wagoneer. Feb 2019 made the last hour and a half back into town on battery alone thanks to the junk output stud insulator and lack of QC - from a AC Delco with GM numbers on the box. All rebuilds, remans, etc are a crap shoot.
Years ago I rarely used electrical stuff from a junkyard. Now, if its original and in OK condition, its my first choice. View attachment 1715449328

Here's the insulator. That's not loose! Junk.
View attachment 1715449325

View attachment 1715449327

This was exchanged for an older AC Delco 'rebuild' which did not have that issue. Yes I opened up and checked it out. Had to clock it anyway.
Click to expand...
If this one has any more problems I’ll probably throw it in the woods and find something else
 
Go to an actual rebuilder and buy one. Might be more $$, but I bet they stand behind it. Heck drive your car there and install it there.
 
There is no doubt rebuilds (and rebuilders) are crap. For some reason I thought maybe powermaster was a tiny bit above. "Maybe not" lol
 
The alternator randomly showed back up yesterday right as it was getting dark out.
I installed it and fired it up and so far it seems to actually be working like it should. Voltage at the output stud is now about 14.5 across the entire rpm range (my neighbors love me).
Didn’t even drain the battery over night!
I can’t really complain because Powermaster has actually tried to make it right and never charged me a dime even though it’s 2.5 years out of warranty.
I guess time will tell if it’s finally right.
E9963A01-9679-444D-845F-018209305D97.jpeg
 
I don't know these. It appears the brush terminal with recessed spade is just clamped to the case as in 1960's Mopar alternators. The other brush terminal with green wire probably goes to a Vreg they install inside the case, though would have to be pretty small to fit. It must sense voltage on the output stud. Good you jumpered the case to BAT- since that was the problem in a rebuilt alternator I once put in my 1969 Dart (not a good ground connection to body), which I solved in the auto store parking lot. Personally, I would rather have an external Vreg since easier to diagnose problems. In my 1965 Dart, I installed one on the inner fender right next to the alternator so easier to follow the wiring.
 
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