Its a pretty simple change. I don't see a reason to do it but this is how to rewire it. Others just replace the mechanical voltage regulator to a VR715 solid state voltage regulator.

 

 

Yes

 

 

Search for D9212S (the "S" is for solid state). It's a plug-in replacement for the mechanical regulator. About $25 from various on-line sources.

 

 

It was simply presented as an alternative to your question about swapping in a 12SI. If you have converted to an electronic ignition, the solid state regulator will provide "cleaner" power; the mechanical regulator can create voltage spikes when the contacts open and close that can take a toll on ignition modules. If you are happy with the current alternator and regulator, then carry on.

 

My biggest reason to switch was capacity. I got an SI rated around 100 amps, way more than the stock unit. I also added Mallory Unilte dist., FI Tech EFI, H4/H1 halogen headlights, etc... Easy swap, Eric's diagram puts the system voltage sense away from the alt, giving a solid 12v plus in the charging system.
Tim

 

 

The tester can load the unit and tell you max output. Generally I like to see voltage drop no lower than 12.5 to 12.75 at full load. Others may have a different voltage they like.
Tim

 

Try and find a GM 12si 94 amp alternator. I find the 10si chrome alternators all fail eventually. The only one that lasted anytime probably put out more like 70 or 80 amps. My current 94 amp 12si Wilson reman on my 88 CSC needs revved to start charging. I do like my 70 amp Chrome Summit 10 DN external regulator. The performance tag said 52 amps at idle and 81 amps at cruise. It has kept up no problem, even when I ran electric cooling fans.

 

The stock regulator in your 10SI, if it's a GM reg., is much better then aftermarkets. If it's still good go with it. I used to rebuild alternators for years, old Chrysler, big pain, but I've seen very few GM regulators fail. Most fail due to diodes. Especially cheap diodes. Hope this helps.

 

On that 12SI. You should not have to rev it to get it to charge. It's losing it charge in the rotor. Try taking a small screw driver.At the rear housing, if I haven't forgot, should have a D hole. Take the small screw driver a stick in the hole and ground it to the rear housing for just a moment. That will excite the circuit and it will keep the charge in the rotor. One way to check if it's charged up is put the screw driver, on any piece of metal, to the rear housing bearing and see if it's magnetized. If it is, your alternator is ready to be used and you should not have to get to high rpm's for it to turn on. I hope this helps and it should solve your problem. If it doesn't then you have a leak somewhere in the alternator.

 

 

I ordered D9212S regulator for my 64, exactly which 94 amp alternator do I need?

 

First, this is a thread about a 1972 Cutlass, and second, it's about converting to a 12SI alternator, which has an internal regulator. What exactly are you asking? If you want to convert to a 12SI, you don't want an external regulator. Maybe you should start your own thread and give us the details about your particular car.

 

Then why were you bringing up the D9212S?