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Square Back Alt versions #2780020
05/31/20 11:36 AM
05/31/20 11:36 AM
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dragon slayer Offline OP
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I realize many may not care since this is 72 and up, but was there an early and later version of the Square back alternator? Early versions with more of stator winding showing between cases, and later version with the stator partially inserted into the case?

I assume this may also mean the rotor and stator not transferable between cases? How about the diode packs? Thanks,

Re: Square Back Alt versions [Re: dragon slayer] #2780119
05/31/20 05:37 PM
05/31/20 05:37 PM
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Andrewh Offline
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I can't say for sure. but at some point in the 80's they go from 60 amp to 78 amp alternators.
so it gets bigger. They still bolt up, but some people had depth issues on big blocks.

parts stores only carry the 78 amp one now.

so no idea on rebuliding or swapping parts.

Re: Square Back Alt versions [Re: Andrewh] #2780143
05/31/20 06:56 PM
05/31/20 06:56 PM
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jlatessa Offline
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Quiz the Dodge Charger Forum.

Nacho will chime in, he's a wizard.

Joe

Re: Square Back Alt versions [Re: jlatessa] #2780215
05/31/20 10:30 PM
05/31/20 10:30 PM
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dragon slayer Offline OP
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Figured it out. Seems like 72 to 75 they retained the front cover like the round back. The stator shows between the cases. The rotor was probably same dimension. In 76 they changed covers so the stator inserts between the covers and you only see about 1/4 ridge of the stator. Stator and rotor changed. Rotor is longer.

Helping friend put chrome covers on existing alternator, and turns out the tuff item is the 72-75. So you need an early square back. Otherwise rotor locks up when case put together, because rotor is longer.

Power Master is modeled after the later square back.

Engineers always working to change something.

Re: Square Back Alt versions [Re: dragon slayer] #2780268
06/01/20 08:42 AM
06/01/20 08:42 AM
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Valencia, España
NachoRT74 Offline
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yeap, those alts with the stator barelly visible between half cases are wider not just on diameter but also on deepth. No matter if 60 or 78 amps, but simply being the 80s alts. I have never tried to fit a later stator on an earlier case actually or if this would make difference on the full size. Sure will look some weird with the ridge around.

Rotor is "the same" at least on size. The difference is really the stator. My alt went bad and once I used an older square back alt rotor I had laying around and worked the same. I couldn't notice any physical difference between my old squareback rotor and the one on the 80s alt.

Diode packs... not phisical diff either. Dunno on ouput capacity, but sure not phisical diff

I made that alt upgrade on my car and, as mentioned on some magazine article ( upgrading the charging system on a 67 or 68 Barracuda ) and for a nice fit some other changes are recomended. On my car what I did is trim around 2 or 3 mms the rear alt spacer to keep the belt aligment.

I also used a longer belt, because the rear of alt met with block, so need to pull away a bit more the alternator from the block, for BB at least. At the end came out perfect. Sure having RV2 compressor the longer distance ( which is already long from factory ) will make slap a little bit more the belts when AC is on, but the diff is no HUGE. I got the belt to set the alt away just enough from the block and get the propper aligment allong with the rear alt spacer.

I think this wouldn't happen on pre 68 setups.... not at least on the belt lenght, but would need the rear spacer trim

Yes, Most of upgraded alternators are based on this later setup, I.E., Powermaster, Dbelectric. HOWEVER Tuff Stuff are using the earlier square back alt per I have being able to check on cars already using those, so if you don't want to deal with the rear spacer trim or longer belt, this could be the way to go. I'd go with them when money is enough for that.


Last edited by NachoRT74; 06/01/20 08:50 AM.

With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: Square Back Alt versions [Re: NachoRT74] #2780525
06/01/20 09:28 PM
06/01/20 09:28 PM
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Mattax Offline
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Nice detective work on the differences.
If you go to buy parts from one of the on-line stores, the later ones are called 'revised' squarebacks.
Heads Up, The Tuff Stuff Alternator I bought is a revised squareback.

It seems that the revised squareback rotors can draw more current when full fielded. We can check that with the service manual specs. I have suspected that this load is more than some regulators can handle. Probably more of an issue when using with an transistorized positive controlling regulator like VR128 that was never made for those currents.

Tuff-6382.JPG-reduced.jpgTuff-6376.JPG-reduced.jpg
Re: Square Back Alt versions [Re: Mattax] #2780542
06/01/20 11:17 PM
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dragon slayer Offline OP
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This was their chrome cover kit. Has both halves with both bearings, pulley and case bolts. But nothing else. We had an original later version to transplant guts. But that did not work for rotor/stator. Found a early 75 model and the rotor and stator worked fine.

Re: Square Back Alt versions [Re: Mattax] #2780557
06/02/20 04:14 AM
06/02/20 04:14 AM
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NachoRT74 Offline
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I know initially tuff stuff sold the "revised" squarebacks, but now ( and maybe since 3 or 4 years ago) they are offering the earlier setup. I have being over this because when time ( and money ) comes I want to be sure they are the correct 74 style. I really wish to get back to the correct year look and more important, the correct belts lenght.


With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: Square Back Alt versions [Re: dragon slayer] #2780558
06/02/20 04:40 AM
06/02/20 04:40 AM
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Originally Posted by dragon slayer
In 76 they changed covers so the stator inserts between the covers and you only see about 1/4 ridge of the stator. Stator and rotor changed. Rotor is longer


I can't tell when it was actually the revised alt design but not sure if it was on 70s. I allways thought that but it seem it was more into the 80s. Anyway, as I mentioned The Beck Arnley 78 amps alt I bought quite ago got the rotor damaged and used the old squareback alt rotod I had to replace it. Side by side couldn't note any physical difference... even both measured something like 5 ohms. And it was my running alt for many years later untill I found a NOS Mopar alt at an old Mopar shop in Venezuela, revised design SUPPOSELLY 100 amps ( per a decal it had ). I bought two alts in fact. One is storaged.

sure I changed the pulley for the smaller one

IMG_1712a.JPGIMG_1714a.JPGIMG_1716a.JPG
Last edited by NachoRT74; 06/02/20 08:09 AM.

With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: Square Back Alt versions [Re: Mattax] #2780580
06/02/20 08:17 AM
06/02/20 08:17 AM
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NachoRT74 Offline
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Mattax... this is a newer Tuffstuff alt. Is hard to see, but is the earlier setup and still 100 amps ( per the guy who posted it at dc.com )

[Linked Image]

Last edited by NachoRT74; 06/02/20 08:35 AM.

With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: Square Back Alt versions [Re: NachoRT74] #2780592
06/02/20 09:04 AM
06/02/20 09:04 AM
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When you look at parts support, looks like 72-75, then the 76 up. I will say the internal diode packs, and capacitor all fit between units.

There also is a difference in the clamp for holding the front bearing in the front case. 3 versions. One is a clamp only like round back, one is clamp and 3 screws type, and one is 3 screws only, no clamp.

Re: Square Back Alt versions [Re: dragon slayer] #2780603
06/02/20 09:35 AM
06/02/20 09:35 AM
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NachoRT74 Offline
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I never have dealt with the "screws only" clamp


With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: Square Back Alt versions [Re: dragon slayer] #2780740
06/02/20 02:27 PM
06/02/20 02:27 PM
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Mattax Offline
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Horizontal brush holder changes for the revised squareback.
An on-line source:
https://www.aspwholesale.com/alternator-parts/chrysler.html

Brush-ID-Isolated-RD-SQ.jpg
Roundback and first gen Square Back

IMG_0016.JPG
Revised Squareback

Re: Square Back Alt versions [Re: Mattax] #2780753
06/02/20 02:43 PM
06/02/20 02:43 PM
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NachoRT74 Offline
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yeap... I recently made this diagram to show how a long attaching screw could accidentally ground that brush ( if goes throught the isolator ). I got that once because the screw used was a selftatting one with a pointy end

[Linked Image]

Last edited by NachoRT74; 06/02/20 02:44 PM.

With a Charger born in Chrysler assembly plant in Valencia, Venezuela






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