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Roundback Vs. Squareback
https://www.slantsix.org/forum/viewtopic.php?t=18377
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Author:  Jeb [ Mon Jul 03, 2006 3:21 pm ]
Post subject:  Roundback Vs. Squareback

Does the squareback alternator have an advantage over the earlier roundback. My Duster has a 50 Amp roundback that I plan on getting rebuilt since it died a few weeks back. Should I switch a later squareback unit? I have been looking at this one from Summit Racing. How are these things on quality?

Author:  SlantSixDan [ Mon Jul 03, 2006 3:58 pm ]
Post subject: 

The advantage to the squareback is at the assembly level (the squareback uses bolt-in diode trios, while the roundback uses individual press-in diodes). There is no operational advantage either way. If you have a complete original unit of either type, and it's never been abusively "remanufactured", go get it gone through and use it. The chrome stuff off the shelf from Summit is just like the chrome (or plain) stuff off the shelf from anyone else except Powermaster: Generic poor quality "remanufactured" junk. (The stuff from Powermaster is built OK but is vastly overpriced).

Another option: Bill Rolik (Bremotorsports on eBay) sells brand-new NOS original Chrysler alternators regularly for between $99 and $124. I've got one on my '71 and one on my '62, and they both work just as perfectly as you'd expect a new Chrysler unit to work.

Author:  Jeb [ Mon Jul 03, 2006 4:05 pm ]
Post subject: 

The roundback I pulled off my car has never been opened since it left the factory. I have a local electrical house that I have used before and does good work. Do you think that they will charge extra to rebuild my alternator since it is a roundback?

Author:  64'4$peed [ Tue Jul 04, 2006 10:29 am ]
Post subject: 

I love the powermaster one wire. 14.3v day in and day out

Author:  SlantSixDan [ Tue Jul 04, 2006 11:58 am ]
Post subject: 

The Chrysler alternators, whether roundback or squareback, usually are not very expensive to have rebuilt properly. But, I cannot tell you what your local shop will charge you! :lol: Do specify that you don't want the housing media-blasted.

Author:  argentina-slantsixer [ Tue Jul 04, 2006 3:33 pm ]
Post subject: 

Quote:
I love the powermaster one wire. 14.3v day in and day out
aren't you burning batteries often? 14.3 seems a tad high IMHO. I have my alternator set at 13.8 and it does a wonderful job and battery does last longer with less voltage charging level coming from the alternator. @14 plus volts my battery last less than 2 years. @13.8 steady lasts 3 years and counting.

Author:  64'4$peed [ Tue Jul 04, 2006 5:49 pm ]
Post subject: 

optima redtop gel battery. interstate dealer says its not a problem. we run these batteries in 15 police cars that have insane draws on the electrical systems. with lead acid batteries we had dead batteries every two to three weeks. optima gel batteries, no dead batteries.

Author:  SlantSixDan [ Tue Jul 04, 2006 6:07 pm ]
Post subject: 

Optima batteries are not the gel type, and they are the Lead-acid type. They are absorbed-electrolyte Lead-acid batteries: The electrolyte (acid) is absorbed in spongelike mats that are wound in spiral fashion around leaden plates, also wound in spiral fashion. This means there's no free liquid electrolyte to spill, the battery can be installed in any position, and provides some other operational advantages, such as excellent resistance to sulphation.

14.3v is a reasonable charging voltage at lower ambient temperatures. Here is a sampling of line voltage specs from the wall of various-make
factory service manuals behind my desk, running from early '60s to late
'90s:

1975 Dodge:
14.9v - 15.9v @ -20°F ambient
13.9v - 14.6v @ 80°F ambient
13.3v - 13.9v @ 140°F ambient
Less than 13.6v @ more than 140°F ambient

1972 Volvo:
14.2v - 14.9v @ -20°F ambient
13.1v - 14.4v @ 77°F ambient

1992 Chrysler:
14.45v - 14.95v @ 0°F to 50°F ambient
13.85v - 14.45v @ 50°F to 100°F ambient
13.75v - 13.85v @ 100°F to 150°F ambient
13.75v @ over 150°F

Remember, charging voltage must be higher with lower ambient temperature, because battery resistance increases with lower ambient temperature.

The master of excessive charging voltage is GM. Has been for decades. They are currently using regulators with ridiculous setpoints in the low 15s. Brake lights were popping like flashbulbs, and DOT pestered them about it in that agency's inimitable way ("Do you think, if it's not too much trouble, you might think about maybe pondering a solution to this problem? No hurry, take your time, and we're not saying you're at fault, or even that there's a problem...we're just asking for the intellectual exercise, pretty much."). GM's "solution": Brake light bulbs rated at 15v instead of 12.8.

Powermaster builds up the same stuff any competent local auto electrics house can build up; it's the "Powermaster" decal that costs excessive bucks.

Author:  64'4$peed [ Wed Jul 05, 2006 1:03 pm ]
Post subject:  optima's

All I know about optima's is they charge fast, last long, and dont leak. I've only replaced two in 3yrs. out of 15. and if those two didn't have excessive draws on em caused by bad wiring they'd still be in the cars

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