Old school alternator

northcreek

Well-Known Member
I'm upgrading the alternator on my plow vehicle from a 78A SI-12 to a 140A CS-144.
Question is: From the L terminal from what I have read, a resistor or light is needed to protect the regulator. I'm thinking it is there to prevent ignition back feed(eng. won't shut off) condition. With my SI-12 a diode was used to prevent this.
I bought a conversion harness with resistor but, wondering if the common belief that it is there to protect the regulator might be wrong like so many automotive myths. Any thoughts ?
 
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northcreek

northcreek

Well-Known Member
I did get an answer from an Ebay seller, so I'll post it for future reference:

"The SI type voltage regulators are tough. They can handle resisted voltage through a light or resistor or a full voltage signal, it doesn't matter for them. So when installing a later CS series with a more delicate voltage regulator, you have to be sure not to send a full voltage signal to the ignition terminal of the regulator. That is where this lead comes in. It adapts from SI to CS and has a resistor as well for the protection of the regulator. It will not prevent ignition feedback. If you needed the diode for that before, you will still need it."

Scott
 

cornchip

Well-Known Member
'When' I get back to my Jeep YJ restoration project....I might need to understand this better. I swapped in a 4200 Vortec into the Jeep. I didn't bother with the stock DR44G and adapted a CS144 140 amp from a Buick Roadmaster. Will I also need this lead? Do you have a link to the Ebay sellers item?

 
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northcreek

northcreek

Well-Known Member
'When' I get back to my Jeep YJ restoration project....I might need to understand this better. I swapped in a 4200 Vortec into the Jeep. I didn't bother with the stock DR44G and adapted a CS144 140 amp from a Buick Roadmaster. Will I also need this lead? Do you have a link to the Ebay sellers item?
This is the one that I needed with the resistor. They have them w/o the resistor if you run an idiot light. You can also get them with different adapter(connector) ends depending on what vehicle you are putting the CS 144 into.
Great alternators that can take a lot of under hood heat with their excellent fan system.

 

cornchip

Well-Known Member
Great alternators that can take a lot of under hood heat with their excellent fan system.

I had a CS144 on a 1995 Buick Lesabre 3800 series 1. Not only did the alternator last the lifetime of the car, the original AC Delco battery died at the ripe old age of 13 years. Good stuff indeed.

So at the moment...I have just a pigtail I snipped from a wreck to fit the CS144. I'll need this adapter myself as it has the resistor built in. Thanks for posting this.
 
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northcreek

northcreek

Well-Known Member
I had a CS144 on a 1995 Buick Lesabre 3800 series 1. Not only did the alternator last the lifetime of the car, the original AC Delco battery died at the ripe old age of 13 years. Good stuff indeed.
No doubt the long battery life was attributed to the CS144 alternator taking care of the loads and the battery just being a storage unit as designed. This is my reason for the swap on my plow vehicle, don't want to destroy another battery..
BTW nice fab job on the mount bracket.. :2thumbsup:
 

TollKeeper

Well-Known Member
Question thats a bit off-topic..

Are these CS144 alternators that you are talking about the GM series 1 wire?
 
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northcreek

northcreek

Well-Known Member
Question thats a bit off-topic..

Are these CS144 alternators that you are talking about the GM series 1 wire?
Not from the factory but, you can get them in 1 wire from places like Powermaster, also with higher amp ratings.
FYI, this is the one that I bought on Evil-bay, got him down to $88 shipped and no core needed like when buying from RA and others.
 
Last edited:

littleblazer

Gold Supporter
I just did this swap on my vette... 17si to cs144... gm sells the adapter as an ACdelco part for like 12$. Best upgrade I've ever done lol. The early ones are identical to what I took out. The later case changed.
 
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northcreek

northcreek

Well-Known Member
Completed the alternator upgrade on my plow truck today and as expected the CS144 handles the load with ease now. Besides the pigtail change the mechanical part is almost a bolt-on, exception being the adjustment bracket since the case is larger than the old SI12. Some say to shim it(raise) with washers but, I decided to slice the bracket in half and weld in a 5/8" filler piece(as shown) and it worked out nice.
100_1630.JPG100_1631.JPG100_1629.JPG100_1633.JPG
 

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