12:00 is the V Sense terminal.
3:00 is the Field Excite terminal.
4:30 is the GND terminal.
There is really no reason to run the GND wire back to the bttys. You can run it to the NEG btty cable, which OEM is on the tranny bell housing. If so, that cable lug should be moved from there to the outside starter bolt.
For a 51a alt I would use a #6 or #4 gauge.
A #8 is allowable, But You Never Get A Second Chance To Overkill It The First Time.
Y’all - check your cable lugs; don't assume OEM ones are good. This was a CTY factory crimp on a C355!!
as for check the lugs, it's all new using an ftz crimper, so if its broke, it's my fault :)
for the B+ i'm using 2awg from the batteries directly to the alt. if i understand what you're saying, the negative post is right next to the AC tap bolt and it should be min 8awg. i can use 2awg for the ground, but i'm afraid the power lugs i have are going to be too large for that bolt. its not the same size as the B+ bolt
the field excite wire i'm taping off the ignition/fuel pump wire from the panel, 12awg.
where does the vsense connect to?
i'm planning to run the bell house ground and some other negative wires to a busbar in the engine bay and then 2awg back to the batteries
and just to double check the starter doesn't have a separate ground it's ground comes from the engine ground right? it just has the positive lug and the solenoid positive wire. is there a reason to use the starter bolt over the engine/tranny bolts as a ground
i think i got everything else hooked up right though, so we'll see, maybe this weekend, if it actually starts up again... :)