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Ok, my old externally regulated alternator is failing in a 1970 cutlass with a 350 engine and I thought about replacing with an internally regulated alternator, specifically the REMY 91310 from Rockauto, rated at 105 amps.
Question is, is this a simple "pull it out and bolt it in" job or is there some wiring to do?
Assuming I'll be doing away with the voltage regulator on the firewall, is it best to completely remove that wiring or should I just cut it and tape it up?
I have done some reading on this conversion but am still a little bit confused about the wiring aspect of it.
I have a dummy light on the dash too that needs to be wired in.
Thanks much,
Mike K.
thanks for the reply, a wiring diagram showing the NEW wiring setup would be nice. And where can I get the new plug for the alternator???
thanks again,
The REMY 91310 is a CS130 as used on the 1988-1990 Custom Cruiser with the 307 motor. It is a bolt-in replacement for your old alternator. Unfortuantely, the wiring diagram (that used to be ) posted above is NOT correct, as it is the one for a 12SI alternator.
The CS130 has a four pin plug, not a two pin plug. First, you need the correct pigtail. This is available at most auto parts stores.
Next, you need to understand how the CS130 works. Unlike the SI-family, you have several options for wiring. The red wire in the plug is the same as the red SENSE wire on your current voltage regulator. Connect it to the threaded post on the horn relay. The wire next to the red wire is the "I" (IGNITION) wire. On some CS130 alternators this is called the "F" (FIELD) terminal. You can connect this to a +12V ignition switched source and this will turn the regulator on. Alternately, the brown wire next to that one is the "L" (LIGHT) wire which has the same function as the FIELD wire on your old regulator. It connects to the brown wire that goes to the GEN light on the dash. This will also turn the regulator on. You can connect either the I or the L terminals or both. The CS130 doesn't care. The last wire is the "P" (PHASE) wire and is used with computer controlled systems on newer cars. You can ignore this. Some pigtails don't even have this wire in the connector. Don't worry about it.
The other thing you need to know is that the CS130 is very sensitive to resistance in the ground path. Run a separate ground strap from the back frame on the alternator to the block. There is a threaded hole in the rear frame of the alternator for this, but be aware that it needs a metric bolt.
This wiring diagram shows the SENSE wire going directly to the BATT post on the alternator. This works but it's the lazy way out. It allows more variation in voltage level since you aren't sensing the resistance all the way back to the horn relay. Personally I'd run that wire all the way to the horn relay instead.
Okay, I have the new alternator in hand along with the pigtail lacking the "P" wire as stated above. Thanks Joe!!! My only question is can I splice the "F" and "L" wires from the pigtail TOGETHER and then to the brown wire coming through the firewall which goes to the dummy light? Or should I just use one of the wires and eliminate the other? Does it matter?
Thanks again,
Mike K.
I will let you all know how it goes when its done. Hope it works, this car needs to get out of my garage and into storage. Snow is coming soon!!
Last edited by mkenny; November 27th, 2015 at 03:37 PM.
My only question is can I splice the "F" and "L" wires from the pigtail TOGETHER and then to the brown wire coming through the firewall which goes to the dummy light? Or should I just use one of the wires and eliminate the other? Does it matter?
No. If you have a GEN light, simply splice the "L" (LIGHT) wire to the brown wire from the GEN light and ignore the "F" wire. The "L" wire is supposed to have the resistance of the bulb in the circuit. The "F" wire is designed not to need that resistance and connects directly to switched +12v instead. The "F" wire is intended for cars with a voltmeter and no GEN light. You can use one or the other, you don't need both connected.
I'm doing this swap as we speak. I'm using the jumper that jumps f to 4 and 2 to 3. I have a question as to what to do with the white, and red wires (2,3) coming from regulator that are now joined as 1. abandon them or put them on the positive post of alternator?
It appears that's where the small red coming off the regulator was on my old alternator?
I'm doing this swap as we speak. I'm using the jumper that jumps f to 4 and 2 to 3. I have a question as to what to do with the white, and red wires (2,3) coming from regulator that are now joined as 1. abandon them or put them on the positive post of alternator?
It appears that's where the small red coming off the regulator was on my old alternator?
In your current harness, the red wire from the regulator connects to the threaded post on the horn relay. This is the SENSE wire that monitors voltage in the system and adjusts the regulator output accordingly. The diagram I posted above shows the short red wire running from the S terminal to the threaded BATT terminal on the alternator. This is the lazy man's way to connect the SENSE terminal and doesn't monitor the voltage drop from the alternator to the horn relay, so it is optimistically high. FYI, being lazy, this is how I wired mine...
The best way to do it is to jumper the red and white wires as you have and connect the white wire to the S terminal on the alternator INSTEAD of the short red wire as shown in the diagram. Either way works, but using the wire that runs all the way to the horn relay will provide more accurate voltage control. If you choose to take the lazy way out, then yes, abandon the red and white wires. You should actually disconnect the red wire at the horn relay to avoid having a hot wire running around not connected to anything. Beware that there may be several red wires on that threaded post, so be sure to remove the correct one.
Keep in mind that you are upgrading the alternator output but putting it through a charging wire that is not able to handle the extra current. In order to take full advantage of the output of the new alternator you need to run either another 10 gauge wire to double your charging capacity or a single 6 gauge wire and bypass the existing charging lead from the threaded post of the alternator to the horn relay post.
I did just this on my 71. Needed a bolt for the top hole in the alternator, but otherwise, some simple wiring and boom! CS130 installed and a working charging system!
Thanks for the help!
Originally Posted by joe_padavano
The REMY 91310 is a CS130 as used on the 1988-1990 Custom Cruiser with the 307 motor. It is a bolt-in replacement for your old alternator. Unfortuantely, the wiring diagram (that used to be ) posted above is NOT correct, as it is the one for a 12SI alternator.
The CS130 has a four pin plug, not a two pin plug. First, you need the correct pigtail. This is available at most auto parts stores.
Next, you need to understand how the CS130 works. Unlike the SI-family, you have several options for wiring. The red wire in the plug is the same as the red SENSE wire on your current voltage regulator. Connect it to the threaded post on the horn relay. The wire next to the red wire is the "I" (IGNITION) wire. On some CS130 alternators this is called the "F" (FIELD) terminal. You can connect this to a +12V ignition switched source and this will turn the regulator on. Alternately, the brown wire next to that one is the "L" (LIGHT) wire which has the same function as the FIELD wire on your old regulator. It connects to the brown wire that goes to the GEN light on the dash. This will also turn the regulator on. You can connect either the I or the L terminals or both. The CS130 doesn't care. The last wire is the "P" (PHASE) wire and is used with computer controlled systems on newer cars. You can ignore this. Some pigtails don't even have this wire in the connector. Don't worry about it.
The other thing you need to know is that the CS130 is very sensitive to resistance in the ground path. Run a separate ground strap from the back frame on the alternator to the block. There is a threaded hole in the rear frame of the alternator for this, but be aware that it needs a metric bolt.
This wiring diagram shows the SENSE wire going directly to the BATT post on the alternator. This works but it's the lazy way out. It allows more variation in voltage level since you aren't sensing the resistance all the way back to the horn relay. Personally I'd run that wire all the way to the horn relay instead.
I am just doing a serpentine conversion using Larry's brackets to use sbc truck brackets on my 70S with the Ford crank pulley. This diagram and swap makes the swap extremely easy plus my horn relay is now a foot away from the CS130 alternator. Great explanation and diagram. Old thread but still very helpful.
November 25th, 2015, 05:00 PM
) posted above is NOT correct, as it is the one for a 12SI alternator. 
