Flathead generator conversion

[tommy]

Your basic 8BA 6v generator. It's white because the stainless cover still has the scratch protector on it. The 2 bolts at 6 oclock and 12 hold it together. Remove the 2 bolts and gently pry the end plate off of the generator body. Careful the end plate is aluminum and after 50 years it can be stuck pretty good. You can snap off a piece if you get too rough with it.



Unlike a pocket watch, no springs and gears will fly across the room when you open it up. No diodes or transistors, just brushes that any idiot with a screwdriver and a wrench can change.



This is the generator body with the field windings inside. This is all you need from a 56-64 Ford 12V generator to convert a 6V unit to 12V unit.



The copper segmented section of the armature is called the commutator. That is the part that the brushes ride on. You can see some arcing in there after dark and the carbon brushes will make it look dirty.



A few seconds with some Scotch Brite or 400 sand paper will clean it up nicely.

[tommy]

Here it is as it goes back together.



These threaded holes in the front bearing plate need to be positioned at 12 and 6 oclock for the bolts to screw into. The body needs to be aligned so that the bolts can pass through it between the field windings. When you look at it, it will be all too obvious.



This slightly out of focus shot shows that the brushes need to be pried back into their housings with a screw driver so that they will clear the commutator as you slip the unit together.



You will need a 12V Ford voltage regulator wired as this crude diagram shows. Tell the pimply parts counter kid it's for a 1964 Ford Failane, 6 cyl, no A/C, P/S or cruise control.

After it's installed and wired, MOMENTARILY touch a jumper wire between the armature and the battery terminals on the voltage regulator to get a spark. This is the procedure for polarizing an externally grounded generator. Other types are done differently.

I know this is very basic stuff to for many of us but it's slightly more involved than bolting on a chromed one wire alternator and there are lots of guys that have built some righteous cars that's never messed with a generator.

[tommy]

Since I'm the only one to reply to this post, I have no idea how it got the 5 stars. itwernt me, but I'll give it one more pass through.

[hotrodA]

Good information. Thanks for posting it with the pics.

[noboD]

Originally Posted by tommy

Since I'm the only one to reply to this post, I have no idea how it got the 5 stars. itwernt me, but I'll give it one more pass through.

Thanks Tommy for the info. I know I've read in a service manual not to use emory cloth on a armature, only sand paper. any idea why?

[Jaypee]

Good info. Thanks Tommy.

Jaypee

[tommy]

Originally Posted by noboD

Thanks Tommy for the info. I know I've read in a service manual not to use emory cloth on a armature, only sand paper. any idea why?

I believe it's because emory is a conductor. If enough gets built up between the segments it can short the two segments together. Each line in the commutator is an insulator between segments. I use Scotch brite which wasn't around when thay wrote service books on generators.

[noboD]

Originally Posted by tommy

I believe it's because emory is a conductor. If enough gets built up between the segments it can short the two segments together. Each line in the commutator is an insulator between segments. I use Scotch brite which wasn't around when thay wrote service books on generators.

Thanks, no one else has even guessed at an answer. Sounds like a good one. One other dumb generator question, when using a growler does a good armature growl or no?

[Flathead Youngin']

Originally Posted by tommy

I believe it's because emory is a conductor. If enough gets built up between the segments it can short the two segments together. Each line in the commutator is an insulator between segments. I use Scotch brite which wasn't around when thay wrote service books on generators.

Thanks again, Tommy. I was really debating on how I could run a Flatty generator on 12v without spending a bunch of cash! I really didn't want to hang a Chebby alt. on my old hot rod...

[tommy]

Originally Posted by noboD

Thanks, no one else has even guessed at an answer. Sounds like a good one. One other dumb generator question, when using a growler does a good armature growl or no?

Well I guessed wrong. I was checking my old motors manual about how a growler works...It had a picture of a mechanic checking the armature with one but didn't go on to explain the process. Since you are checking for hidden shorts, my guess would be that a short would cause it to growl but I'm 0 for 1 on guesses today.

There in the book it said never to use emory cloth because bits of emory can get embedded in the segments promoting rapid brush wear. Emory must be some pretty hard stuff.

Well I'm either 0 for 2 or batting .500

It was interesting how the book tells you not to just discard a shorted armature but gave several possible cures to repair it. There is a lot of interesting reading in one of those old blue Motors Manuals. They were written for repair mechanics not parts changers...back when labor was cheap.

[Mr 42]

This one is for the Tech Archive.

Ive been running a conversion like this for two years and it works Great(put out up to 35 amps).

A small tip you if you push the brushes outward you can hang up the spring against the brush. And after you have mounted the plate, you can give the brush a push with a screwdriver, thru the generator body slot's.
The makes assembly a breeze...

[pigpen]

Excellent tech post!

pigpen

[Psychobilly Boi]

hey crew,

excellent post!

danny

[burger]

Tommy,

Thanks for posting this! It may be old hat to the old timers, but to us young guys who are used to just replacing the alternator at the first sign of trouble it's nice to see how to actually repair something.


Ed

[NOBILLETA]

Just as a minor addition, If memory serves me correctly (and these days thats not a given) with a growler the armature is considered good or bad by holding a hacksaw blade slightly above it in several positions, if the blade is magnetically drawn to it, it's good . thats the way I remember it anyway.

[Flathead Youngin']

Hey, Tommy, great thread. I'm getting ready to hook up my generator in a week or so.

I bought a generator from a good ole fella that said he just converted it.....it looks real good (new paint makes anything look good, huh?). Anyway, mine has two wires coming out of it. They go directly into the top of the generator (where the little metal cap belongs) and does not attacth to the posts- like supposed to. I removed the metal dust cover and it looked to have 3 brushes but only two wires coming out. How can I tell which wire is which?

I assume this 64 regulator will work on this one too...

[alchemy]

Originally Posted by Flathead Youngin'

Hey, Tommy, great thread. I'm getting ready to hook up my generator in a week or so..........I removed the metal dust cover and it looked to have 3 brushes but only two wires coming out. How can I tell which wire is which?

If your generator has three brushes, it's a different animal than most guys use. I think they stopped using those in '38. I also believe the later 12 volt housing and fields are not gonna be compatible with that '38 armature and rear plate.

Tommy used an 8BA generator, but a '40 - '48 can also be used the same way in a 12 volt conversion. The later 12 volt parts go onto both of these the same.

[Flathead Youngin']

Originally Posted by alchemy

If your generator has three brushes, it's a different animal than most guys use. I think they stopped using those in '38. I also believe the later 12 volt housing and fields are not gonna be compatible with that '38 armature and rear plate.

Tommy used an 8BA generator, but a '40 - '48 can also be used the same way in a 12 volt conversion. The later 12 volt parts go onto both of these the same.

I noticed this when I was telling grandpa on the phone. So, wonder how in the world this fella converted this 3 brush genny to 12v? I assume he just didn't hook up one of the brushes but wonder what commutator he used. I would have asked him, but I ASSUMED that he just what Tommy is showing.

So, you think the later 12v commutators will work in 8ba style (Tommy showed) AND the 2 post 38-48 (or so) BUT not the earlier 3 post......

Since I still have two wires coming out of mine, can I use the same regulator that Tommy is showing?

[tommy]

Originally Posted by Flathead Youngin'

Hey, Tommy, great thread. I'm getting ready to hook up my generator in a week or so.

I bought a generator from a good ole fella that said he just converted it.....it looks real good (new paint makes anything look good, huh?). Anyway, mine has two wires coming out of it. They go directly into the top of the generator (where the little metal cap belongs) and does not attacth to the posts- like supposed to. I removed the metal dust cover and it looked to have 3 brushes but only two wires coming out. How can I tell which wire is which?

I assume this 64 regulator will work on this one too...

Yeah, that sounds like a 36 6V gen. I had one on a 36 P/U. It used a "cut out" (a small round sheetmetal box on top of the generator) and didn't have a V/reg. I always parked it on a hill in case the cut out points stuck. When they stick the battery drains down. They have modern fixes for that but they are 6V anyway.

I wasn't sure what year bodies were the same diameter as the later 12V bodies. I'm sure alchemy is right. Sounds like you need a newer 6V generator to convert. Now if you need the fan mount generator pulley ...then you have another problem. If the 40s era generator will work in your application, then they should be easier to find.

[tommy]

Originally Posted by Flathead Youngin'

I noticed this when I was telling grandpa on the phone. So, wonder how in the world this fella converted this 3 brush genny to 12v? I assume he just didn't hook up one of the brushes but wonder what commutator he used. I would have asked him, but I ASSUMED that he just what Tommy is showing.

So, you think the later 12v commutators will work in 8ba style (Tommy showed) AND the 2 post 38-48 (or so) BUT not the earlier 3 post......

Since I still have two wires coming out of mine, can I use the same regulator that Tommy is showing?

You change the body with the field windings. The armature with it's commutator is still the 6V armature. The 6V 2 brush end plate stays also.