Alternator output stud

[1973dust]

Simple question for you electrical gurus. Should the alternator output stud be able to rotate at all and, if not, is that a possible diy fix?

 

[1973dust]

On further investigation the stud and insulator have slight rotational play in the alternator case. Normal?

 

[413]

Not Normal, not good. There is an insulating washer and a nut that holds it tight. Then you put on the terminal and another nut when installing.

So gently tighten the first nut.

 

[1973dust]

Thanks, I'm not at home now but I think I only have one nut. The stud and "squarish" insulator move like they are one piece but the insulator has play in the case. It's a dual field.

 

[Mattax]

1. It's not great.
2. Yes you can fix it, but it requires removing and opening the alternator case.

There's a few different ways the stud was attached. What alternator is on there?
Off the top of my head there are two ways I've seen a standard squareback done.

 

[Mattax]

If its an unmolested original, inside there will be a second nut holding it tight to the positive rectifier. Here's one I cleaned up.

and it will have what looks like mica insulating washers seperating the rectifier from the housing.
They're fragile.

The rest of the assembly looks like this, but probably no reason to take it all out.

 

[1973dust]

Thanks, that helps tremendously. It doesn't look like it will be too bad of a job. I assume it being loose has probably been causing some arcing internally? It's charging fine. I just noticed it was loose because I was hooking a direct wire from the alternator to the battery.

 

[Mattax]

Well once you do that you'll never know if its charging the battery.
You may know if the battery is discharging.

If the stud was so loose there was only intermittant contact on with the positive rectifier, then the ammeter would flicker to discharge. Yours probably needs just a little snug.
I had that with a brandy new AC-Delco alternator in my Grand? Wagoneer. Fortunately I had about an hour before sunset to make it the rest of the way home. Fortunate because I just grabbed a late lunch after a multi-day trip. Brand new, OEM name, and still junk. Cockeyed insulator prevented the nut from staying tight.

 

[1973dust]

I already bypassed the ammeter a couple of years ago after hearing several meltdown stories and just recently installed headlight relays. I'm trying to remove as much load as possible from the factory wiring although it's in decent condition. I was intending to install a voltmeter.

 

[413]

They are quite different between the squareback as pictured above, and a round back 1960-1972.

 

[1973dust]

I'm certain mine is as above. It's from a 74.

 

[1973dust]

Mattax, could you clear your inbox?

 

[Mattax]

Sorry. Not at this time.
Long story version there's a lot in there and its probably faster for me to get inot paypal and re-up my gold membership.

If its somehting you don't want to post here. Go to 'about me' and send me an e-mail from my webpage.

 

[1973dust]

Well once you do that you'll never know if its charging the battery.
You may know if the battery is discharging.

Thanks again for the pics and info on the alternator. I hope to get a chance to repair it tonight. I'm curious if you feel there are any other drawbacks to a direct charge wire other than rendering the ammeter ineffective. I was doing the direct charge upon recommendations I found on here but now I'm finding some people saying that it defeats the factory wiring protections and actually could increase the risk of a wiring meltdown? I seem to be getting more confused the more research I do. I have no abnormal electrical loads in my car nor do I intend to so maybe I shouldn't do the direct charge although I just finished installing it? I've also already installed headlight relays with the Toyota kit although I now understand that they need to be powered direct from the alternator rather than the battery. The initial research I had done said the bypass would cut the current carried thru the bulkhead connector in half which seemed like a good idea and I found no mentioned drawbacks except for the ammeter no longer functioning. By the way, your website is pretty cool. I've been getting into handling more the past few years and it looks like you have some good info accumulated there. Thanks.

 

[Mattax]

I'm curious if you feel there are any other drawbacks to a direct charge wire other than rendering the ammeter ineffective. I was doing the direct charge upon recommendations I found on here but now I'm finding some people saying that it defeats the factory wiring protections and actually could increase the risk of a wiring meltdown?

Depending on how its done, yes it defeats the fusible link.
One could add a second fusible link or a 'maxifuse' and regain some of the protection.

The fusible link provides some protection against the battery getting shorted to ground.
For example, if your buddy was helping while tightening the nut on the alternator's terminal accidently touched the wrench to the bracket.
First there would be sparks. Then he panics leaves wrench there while running to get help. Instead of the 12 gage wires all getting fried (and every connection in the line), the 16 gage fusible link wire melts in a relatively safe location of the engine bay.

With a direct wire added from the battery to the alternator, there are two paths for the current to reach ground. With a fusible link in both lines, it will probably burn the direct line first as its the shortest distance, and then the original path second.

There have been people here who have had bad ammeters. Or more precisely, ammeters that seemed to go bad causing a break or poor connection in the circuit. Redfish posted that he had observed early 70s models in particular had windshield leaks in that corner causing electrical corrosion. I suspect another contributor to failures is using the alternator to charge very dead batteries. Probably happens more when cars aren't driven as often.
If the ammeter posts are loose, its problem or will be. Otherwise I think the whole thing is Chicken Little.

1973 has some crazy circuit paths. We've had at least two guys here with the reverse light wires grounding onto the transmission and taking out the fuse for four seemingly unrelated items. I think '73 also has the 'engine connector'. According to Redfish it was there to make it easier for engine installation at the factory. But it adds another connection to the ignition and other critical circuits.

I've also already installed headlight relays with the Toyota kit although I now understand that they need to be powered direct from the alternator rather than the battery.

I have the kit myself, but I haven't installed it yet. The harness is going in my '85 Grand Wagoneer. Same headlight circuit as A-bodies but slightly heavier wires. Yes the shortest distance is direct from the alternator.

If you are keeping the direct wire from the alternator to the battery positive, it doesn't matter as much where the power is drawn from. But if returning to the factory wiring concept, then yes power it from the alternator. Modern cars are generally direct wired to the battery, but even in old cars the accepted terminology for system power is 'battery' and '12 volts'.

I probably should have begun with this. Instead of asking anyone to believe someone else, lets jsut explain what's going on. Then you can decide what makes sense.

The alternator creates power at roughly 14 Volts.
The battery stores energy at roughly 12.5 Volts.
In the car they are both connected together. One comparison is a water pump and a storage tank connected together. If we have 14 psi at the pump, water will flow from it before any water flows from the 12 psi storage tank unles there is some strange path or a restriction to flow from the pump.

When a drawing says 12 V or Battery it usually means system power, which can be from either Battery (12.8 Volts or less) or Alternator (13.8-13.9 Volts.)

Guys that have a direct wire and the ammeter report that the ammeter shows discharge for starting etc pretty much like normal. But the ammeter doesn't show charging. So the charging path is shorter, and the electrons bypass the ammeter. But for normal battery functions, the path through the ammeter is shorter.

The initial research I had done said the bypass would cut the current carried thru the bulkhead connector in half which seemed like a good idea and I found no mentioned drawbacks except for the ammeter no longer functioning.

Unfortunately those guys didn't tell the full story.
Sometimes they even make the big mistak eof claiming all of the cars power goes through the ammeter.
The ammeter only shows battery charging and discharging. Electrons only flow through it when the battery is discharging (start up and emergency power) and when the battery is recharging. The car's power comes from the alternator, and car ammeters do not show alternator output. (Even though its common to say alternator charging - the phrase really makes no sense).

Using orange arrows to represent flow. Engine running, stepping on the brakes, battery fully charged.

Ammeter does nothing. It just maintains the connection to the battery.
If the alternator stops working properly, the ammeter will show the battery discharging as it takes over supplying power.

 

[1973dust]

Depending on how its done, yes it defeats the fusible link.
One could add a second fusible link or a 'maxifuse' and regain some of the protection.

I've got twin #10 wires with a 50 amp Maxi fuse at both ends of each directly wired from alternator output stud to the starter relay stud. I'd rather leave it since it's already done but if unsafe I will remove.