New alternator, something's not right.

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/6 Matt

/6 Matt

30 Degrees Crooked
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So I got a new alternator at my local autozoo because the one it had on it had a feild going out.

So when I got the new alternator and tried putting it in, I noticed something different.

The old alternator had the hookup for BAT, FEILD and GRND. On the other side of the case was a marking GRNDW and it didn't have a connector there of any sort. The new alternator has a connector on GRNDW but not GRND. The Dark Blue wire went to GRND.

So I assumed that this was only a minor difference in the parts, cause they had the excat same part number, same alternator, this is the only difference. So a quick cut and splice later to put the appropriate connector on the dark blue wire, I hooked it to GRNDW and plugged up the regulator. As soon as I turned the ignition key on, the ammeter pegged to D so I immediately cut the key back off.

A quick reference to the 70' wiring diagram I got, shows. Dark blue ties into the "I"(?) side of the regulator and goes to the balast resistor and appears to be the ground for the exciter (?). This wire then travels half way accross the page to the ignition switch.

The dark Green wire, connected to FEILD goes directly to the "F"(?) side of the regulator. I'm assuming this is the hot side of the exciter (?).

So question is, what the hell is going on here?
 
In the past I have seen back parts of alternators a 1/4-1/2 turn off,and would have to re-position them.When buying a new unit you have to check every thing about them as you can get the wrong one or wrong position or the wrong terminals and location.If its the right unit,you can ask that they re-position it.Now you might have fried the unit or it could be a internal fault with the unit.You have to bring it to a independent place to test it.You only re-configure a wiring harness if you know 110% what you are doing,if not leave it alone.Do the job right and get the proper unit and location,mrmopartech
450 424 0445
 
OK, ignoring amp ratings, but within the "normal" frame Mopar alternators, that is, ignoring the large frame 100+ amp units, there are FOUR major departures

1---There is the origninal 60-69 grounded field alternator. Has only one brush connection, the other is permanently grounded

2--Rebuilders frequently take the above unit, drill a hole in the frame and mount a second insulated brush holder to convert the unit for 70/ later. This can cause problems because sometimes the original grounded brush is installed, so the field is still grounded anyway

3--Very early (70--71?) "round back" FACTORY isolated field which has two factory insulated field connections, but "looks like" the old unit as it's a "round back."

4--Later "square back" which has the later rectangular heat sink in the back half of the frame, and which comes ONLY in isolated field

NEXT

You need to know WHAT regulator you have? Do you have the 69/ earlier, or the 70/ later?

If you have the 69/ earlier, like this:

You can use ANY of the above types of alternators, simply by grounding one brush if it has not been already, and using the insulated brush (field) to hook to the green regulator terminal

a64736b139848eabbf7f4b_m.JPG



BUT if you have the 70/ later regulator like this:

Then you MUST have an alternator with TWO isolated (insulated, or incorrectly called "dual field) alternators

a6473a71398477cdaff217_m.JPG


In the photo below, the LEFT one is an original grounded field "roundback." (69 or earlier) The one on the RIGHT is contradictory. It has BOTH mountings for BOTH a grounded brush (at 9 o'clock), and an ISOLATED brush (at 3 o'clock) The top brush at 12 o'clock in both is installed






The photo below is a "normal" early 70's (71/2?) "isolated field" unit. It has two isolated/ insulated brushes and NO grounded brush, nor does it have a place for one



The photo below is a "rebuilder hack." This is a pre--70, roundback, "grounded brush" or "grounded field" unit that some rebuilder has drilled an extra hole into in order to mount an isolated brush. Once again, the trouble with these is that nowadays, you see them with isolated, grounded, or BOTH brushes



The photo below is a late 70s "squareback," available ONLY in isolated field. You can use ANY isolated field unit on a 69/ earlier regulator by grounding either brush (field) and hooking your green regulator wire to the remaining terminal

 
Mrmopartech said:
In the past I have seen back parts of alternators a 1/4-1/2 turn off,and would have to re-position them.When buying a new unit you have to check every thing about them as you can get the wrong one or wrong position or the wrong terminals and location.If its the right unit,you can ask that they re-position it.Now you might have fried the unit or it could be a internal fault with the unit.You have to bring it to a independent place to test it.You only re-configure a wiring harness if you know 110% what you are doing,if not leave it alone.Do the job right and get the proper unit and location,mrmopartech
450 424 0445
Click to expand...
Are you talking about the internal parts of the alternator being off or what? I'm confused. At the moment nothing seems to be fried, I hope I'm right, I only kept the key on for less than 1 second. At the time I did this, I was 110% sure that I knew that all things being equal the ground location moved.

67Dart273 said:
OK, ignoring amp ratings, but within the "normal" frame Mopar alternators, that is, ignoring the large frame 100+ amp units, there are FOUR major departures

1---There is the origninal 60-69 grounded field alternator. Has only one brush connection, the other is permanently grounded

2--Rebuilders frequently take the above unit, drill a hole in the frame and mount a second insulated brush holder to convert the unit for 70/ later. This can cause problems because sometimes the original grounded brush is installed, so the field is still grounded anyway

3--Very early (70--71?) "round back" FACTORY isolated field which has two factory insulated field connections, but "looks like" the old unit as it's a "round back."

4--Later "square back" which has the later rectangular heat sink in the back half of the frame, and which comes ONLY in isolated field

NEXT

You need to know WHAT regulator you have? Do you have the 69/ earlier, or the 70/ later?

If you have the 69/ earlier, like this:

http://stores.atlaschrys.com/media/03/a64736b139848eabbf7f4b_m.JPG

You can use ANY of the above types of alternators, simply by grounding one brush if it has not been already, and using the insulated brush (field) to hook to the green regulator terminal

BUT if you have the 70/ later regulator like this:

http://stores.atlaschrys.com/media/01/a6473a71398477cdaff217_m.JPG

Then you MUST have an alternator with TWO isolated (insulated, or incorrectly called "dual field) alternators
Click to expand...
I have the 70+ regulator and what appears to be a a round back alternator simply missing a brush connection.
 
67Dart273, in the pictures you supplied, the new alternator looks like the one on the left in that picture that has two round back alternators on it. The old one looked like the one on the right and the one in the drawing below.
 
For me the solution is simple. Take that one back, and get one that's a squareback. I'd ask for about a 75 A body, and do NOT accept a round back. If AZ won't cooperate, get your money back and go somewhere else.
 
67Dart273 said:
For me the solution is simple. Take that one back, and get one that's a squareback. I'd ask for about a 75 A body, and do NOT accept a round back. If AZ won't cooperate, get your money back and go somewhere else.
Click to expand...
Is the squareback on better than the roundback alternator? Other than the fact that the mod you mentioned to make a pre-70 work with electronic regulators going wrong?

I probably won't be able to get a squareback one without paying for it, the alternator I got today was replaced under a lifetime warranty from a reman I got back in 2006, so it was free.
 
Well the thing is they seem to have given you the wrong alternator, so even if it was free, they should make good on giving you the right one.

The squareback outputs more power at less shaft RPM, so yes, it's a better design.
 
You seem to have the same alternator that I was sold for my '71 Duster. 3 threads before yours .. "new alternator and voltage regulater - no charge".

I learned a couple of lessons along the way and got some good advice. You might find the thread worth reading so you won't repeat my mistakes.

Ken
 
I actually did read through the thread you had ken and I did learn something between both our threads, I'm just electrical stupid and needed a clear cut answer spelled out to me. Sorry about that guys. I am learning though! :mrgreen:

I have one final question!

I got a squareback alternator now and a new regulator (the other got fried). This square back has the battery connection, and two FEILD connections. Both FEILDS are blade style connections, one connector is in the vertical connection pointing torwards the hood, another is horizontal pointing torwards the rockerarm cover. I THINK, the blue wire needs to go on the vertical connector and the black wire on the horizontal one. Is this right? Or does it even matter which wire goes on which connector? I'm leaning torwards it doesn't but I want to make sure before I hook something up and fry another regulator.

Now for the explantation as to what happened...

Duralast stopped making the 70-72 roundback and changed the part number the the square back. BUT, the one store I went to got the 60-69 roundback labeled with the same part number. When they directed me to another local branch that had both round and squarebacks in stock as well as the regulator I went there. When the man pulled the roundback number and went back in the store to get it, he came back with a box that procured, a squareback! With a label reading 70-81 chrysler charging systems, even though that number on the computer showed us a picture of the 60-69 roundback the first store showed me! :cheers: You know, it really doesn't help that the factory did confusing bs changes back whent he car was made, but now 40+ years later duralast is making changes to add to the confusion.
 
GREAT. You are makin progress. Does not matter which field terminal the green/ blue goes to, other than wire slack
 
67Dart273 said:
GREAT. You are makin progress. Does not matter which field terminal the green/ blue goes to, other than wire slack
Click to expand...
Awesome!! Thank you so much for contributing your knowledge to a young gun with no clue what he had going on!
 
It works! Wired it up, keyed it on and no short! Startup yeilded 14.1 volts!:cheers:
 
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