6V Pos. ground Flathead V8 generator wiring

kkarlsrud

kkarlsrud

Junior Member
Hey everyone! I have a '41 Flathead in my '28 roadster pickup and am working on wiring the engine. I was told to get a voltage regulator for wiring, so I did. I was able to have my generator rebuilt locally and they verified the cut out on it was in good working order. I have been told I should not run both the cut out and the voltage regulator as they are one in the same. Is this true, and does anyone have a diagram for wiring a 6v +ground generator off of a cut out? I'm trying to get the truck driving so my family and I can enjoy it for the summer.

Thanks in advance!
 
In my opinion, it is the other way around. If you have a voltage regulator, don't run the cut-out. By 1941, all fords had voltage regulators, which are superior to cut-outs. Unless you have an odd mix of old and new stuff, forget the cut-out.

I think we need a little more information on what you actually have.
 
You need to establish what year type of generator you have. Is it a two brush generator which would require a 3 unit voltage regulator, or is it a 3 brush generator which requires the round ford cut out on top of it ? Regards, Kevin.
 
41 used a regulator and not a separate cutout. Your 41 generator has one terminal in the rear end plate which is the "A" armature (unmarked) and two terminals on the side of the main body. The top terminal is "F" field and the main body should be stamped such. The lower terminal is "G" ground, it will not be marked. There should also be the letter "B" stamped next to the field terminal. That letter B indicates the field winding are of 18 gauge wire, which is good since this will increase the life of the regulator contacts and reduce arcing. The earlier than 41 generators only have two terminals, A & F. To get technical the main body should also have the Ford script stamped and next to it the date code starting with the letter "U or V" (for 1940 or 1941) and followed with a number indicating the month of the year manufactured.
The voltage regulator has a cutout built into it so a second cutout is not necessary.
 
Last edited:
Thanks for all the helpful info everyone. I guess I should have posted a picture of the generator I'm running. I'm assuming it's a '41 as that is what year we found the block to be and it was fully assembled when I got the engine/trans.
It's hard to see, but the best picture I could find this morning.
 

Attachments

  • engine.jpg
    engine.jpg
    66.8 KB · Views: 119
Appears to be much earlier than 41. Looks like a three brush unit that will not need the regulator. The output side of the cutout should go through your ammeter gauge and to the battery -
 
Terry said:
Appears to be much earlier than 41. Looks like a three brush unit that will not need the regulator. The output side of the cutout should go through your ammeter gauge and to the battery -
Click to expand...

Thank you Terry! That helps a lot!
 
IF... your generator is a 3 brush unit, came with and has a cutout on top, that is a pre-1939 generator and does not use an external mounted regulator. The output connection on the cutout goes to the ammeter, from there to the battery minus post, not the positive. All old Fords were positive ground.
Google the wiring diagram for the '35 Ford, it's simple wiring as to the charging system.
 
Yep, you have to know which generator you have, it's either a 3 brush or it's a two brush, those have the output terminal on the rear end-plate, the field and ground are on the top.
 
You must log in or register to reply here.
Back
Top