Alternator w/ built in voltage regulator

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amg2y

Joined
Sep 12, 2005
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Quick question for electrical gurus out there. Background '68 FJ40 with 327 small block, 3 speed on the floor. Wiring had been redone by PO, so I could tell the color of the wires anymore. Problem: I think my alternator is dead. My question is "Can I get a new alternator with built in voltage regulator to replace mine?" Currently I have both alternator and voltage regulator set up. Thanks a bunch....:cheers: :cheers:
 
yes u can, i have it on my 40 with a 350 but i dont have access to the part number or the 40 right now. I dont think they are hard to find, basic gm alternator internally regulated.
 
funny story about why i know you can:

driving in east san jose at night my brother and i were on capital expressway, when the truck started sputttering and backfiring, lights were running dim. It backfired sooo loud numerous times that by the time we pulled over two cop cars came rushing behind us into the supermarket parking lot with guns drawn. They thought we were shooting out of our open top cruiser. Its not the best neighborhood.

At that point we got rid of the toyota voltage regulator (that was the cause of the battery dying and sputtering) and got an internally regulated alternator.
 
hmm, I wonder if that's the same cause on my 40 too. Mine also sputtering and backfires when I floor the gas pedal after shifting. Thanks for the reply Ravi.
 
Delco 12si common as dirt
 
Thanks Grant... Wiring diagram should come in the box right?
 
they are real simple....on the back they have terminals #1 & #2 #1 needs a hot wire when key is on.. #2 just jumper over to the large lug to the battery connection...
 
another option is to go with an AC/Delco one wire alternator, local landcruiser shop who has done several conversions recommended this as it maintains the original amp meter, which feeds back through. Not exactly sure the part number either but ac delco one wire and most places will know what you are talking about.
 
There is a down fall to the one wire..
In one wire operation, the alternator will not begin charging until the engine rpm reaches a threshold. This rpm threshold will vary with pulley size but generally speaking it is anywhere from 1200 to 1600 rpm. The reason for this is that the alternator itself generates a small amount of current to the voltage regulator and this turns on the voltage regulator. The alternator needs to spin fast enough to generate enough current and thus the situation where when the engine is started, it is necessary to rev the engine to actuate charging. They have been proven to be unreliable in 2 aspects....#1 poor or no charge at idle...#2 voltage regulator tends to hang,, that is ..it remains energized after shut down occurs causing a drain on battery.... The plain jane 12si does maintain the normal function of the volt or amp meter which ever applies..The plain jane 12si will begin charging when it detects battery drain. Thus, when you start the engine and run it at idle, the alternator will automatically come on when required. The alternator will continue to run from that point onward. The simple 12si is really the ideal set-up. Also available in various amps to suit your needs
 
get the 84 camaro 12si for the 305 v-8 its rated at 95 amps but will put out 55 amps at 1200 rpm and up to 115 amps at higher rpm. any parts place will have them.

oh and if you havnt seen it, check out www.alternatorparts.com lots of info on alternators and how to ID them etc.
 
What about a Delco cs130?
 
The Delco CS 121 or 130 is also an excellent choice.. available in amp range from 60 to 120..the overall case diameter is larger than the 10 or 12si, making it less desirable on some applications.. on a standard 2F right side mount location, the bracketry must be ground down, and one gusset on the unit itself must be eliminated to obtain full movement for belt adjustment..same holds true on Vintage Air applications.. but is a bolt on for a GM..it is a four wire configure but only 2 are needed, the larger red wire, jumper to the Batt. terminal on the rear case.. the one next to it( some times brown or green) requires 12Vs w/ key on only.the remainder can be discarded..Used as the most common standard unit on GM cars and light trucks, from '86 to'96.. Also used in industrial, marine, and agriculture applications......
 
I run a leece neville on my 60. Units are big, reliable, and put out some real power. Mine is a 200 amp model. These are used on ambulances, fire trucks, big rigs, etc. The only connections I had to make were to the battery and to ground.
 
what I did was find an old POS Delco. Took it to the alternator repair shop. Told them I wanted to make it a one wire and put out about 80+ amps at 2000 rpm. Also picked up a smaller pulley, helps. Cost me $100. Some changes you have to do to take out the external, wiring stuff, but you can find it on the internet, how to diy.

The rebuilt alternator supports my dual batteries and charges up real fast.

I think this is the cheapest and most reliable route. The hardest part will probably be making a bracket and lining up the pulleys. Which ain't that difficult.

Good luck.

John
 
I found that although the one wire has to reach a certain rpm to kick on the charging process, once it does, even if it falls down to idle, it still charges. This was a nice surprise.
 
Just jumping in with a question... I have just installed a Painless wiring harness, and the 40 runs but the alternator isn't charging the battery?? My alternator has an internal regulator, but there is only a BATT lug and a D+ terminal. i'm supposed to run a small light from the D+ terminal and then to ground (which i haven't done yet) and i have the BATT lug running through a 50 amp fuse and then to the starter motor, which has a lead running to the battery. Does anyone have any ideas? Should i just run the lead from the alternator, straight to the battery, will that make a difference?
 
DeanDavs said:
Just jumping in with a question... I have just installed a Painless wiring harness, and the 40 runs but the alternator isn't charging the battery?? My alternator has an internal regulator, but there is only a BATT lug and a D+ terminal. i'm supposed to run a small light from the D+ terminal and then to ground (which i haven't done yet) and i have the BATT lug running through a 50 amp fuse and then to the starter motor, which has a lead running to the battery. Does anyone have any ideas? Should i just run the lead from the alternator, straight to the battery, will that make a difference?
Click to expand...

What brand name and model are you referring to?? :confused:

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Its a Bosch Alternator, it has been rebuilt a couple of times though!
 
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