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Replacing a 6 V generator with a 6 V alternator

Started by VooDoo, March 11, 2023, 03:34:58 PM

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VooDoo

So, according to my mechanic, my generator is not charging my battery correctly on my 1937 75 Series. Since I need to replace it, I was wondering if anyone has replaced a generator with a 6 V alternator? I've been reading, and it seems like the alternator would provide more power, especially at night, driving with the lights on. I plan on driving my Caddy for wedding events and such so I need to make sure that everything is top notch. Anyone have any experience with this and or recommendations? I can always buy a rebuilt generator but I kind of figured if the alternator is going to provide me with better charging, etc. then why not go that route? Thanks guys I really appreciate it. I'll post this in the general discussion section just in case more individuals are viewing that but moderators, Please feel free to remove it if need be. I need to get this sorted as quickly as possible.
Andy Fulenwider
1937 75 Series Convertible
1947 62 Series Custom Project

signart

Very pricey, but google GenerNator.
They convert original generator housings to alternators, 6,12, or 24 volts.
Art D. Woody

Jim Miller

I have a 6 volt GenerNator on my 41 and 49. Been very pleased.
Jim Miller

1941 6219
1949 6237X
1970 CDV
2021 XT6
Past:
1991 SDV
1999 DeElegence
2006 DTS
2013 XTS
2016 SRX

Jeff Rosansky CLC #28373

There is a YouTube guy named Paul Shinn. He does Model A's.
He has a video on converting a 12v GM alternator to 6v with just a few parts.
Might be worth the watch.
Jeff R
Jeff Rosansky
CLC #28373
1970 Coupe DeVille (Big Red)
1955 Series 62 (Baby Blue)
Dad's new 1979 Coupe DeVille

VooDoo

Thanks for the responses. I did as somebody else suggested, and tried to polarize the generator didn't really seem to do much. The car is all original for the most part. Well at least time period Correct. Didn't really want to mess up the look if need be, but reliability is more important to me. I know the price of the 6 V alternator is kind of pricey, but there may seem to be advantage of going a 12 V upgrade. The car is not judged and I don't really have any intention of it being. I really care more about reliability. If I converted to 12 V might solve a lot of issues but I wonder how difficult it would be to put in step down resistersto convert the 12 V or 6 V so I don't mess up my instrument panel?
Andy Fulenwider
1937 75 Series Convertible
1947 62 Series Custom Project

TJ Hopland

A resistor doesn't work well on loads that could vary.  Close enough for instruments?  Maybe?

There are electronic converters you can get to reduce 12v to 6v for the things that are not practical to swap out.  You do have to watch the current rating. The bigger ones are maybe 3 amps and many are less so know the loads you plan to run and buy the right unit.

Its a tough call on a car especially one like a Cadillac that has lots of stuff. It kinda ends up being a can of worms with one more thing that has to be done or changed.  Its a lot easier and more of a 'no brainier' on something like a tractor that has little to no accessories. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

VooDoo

Quote from: TJ Hopland on March 13, 2023, 02:05:35 AMA resistor doesn't work well on loads that could vary.  Close enough for instruments?  Maybe?

There are electronic converters you can get to reduce 12v to 6v for the things that are not practical to swap out.  You do have to watch the current rating. The bigger ones are maybe 3 amps and many are less so know the loads you plan to run and buy the right unit.

Its a tough call on a car especially one like a Cadillac that has lots of stuff. It kinda ends up being a can of worms with one more thing that has to be done or changed.  Its a lot easier and more of a 'no brainier' on something like a tractor that has little to no accessories. 

So converting 12 V would solve a lot of issues, but then also be more involved and more costly than say a 6 V alternator? And a 6 V alternator would give me better performance when it comes to starting and driving with lights on at night etc. Replacing the generator would be the cheapest route and the 6 V alternator about double that cost for the part if I'm understanding all this correctly?
Andy Fulenwider
1937 75 Series Convertible
1947 62 Series Custom Project

VooDoo

I do have a generator off of a 47 motor at my house. Not quite sure the condition of it. The generator on my 37 looks to be a two brush generator but I can't for the life of me crack open the slots to check the brushes. I was wondering if these generators interchange maybe I could have my mechanic simply swap it out and hope for the best. 😬
Andy Fulenwider
1937 75 Series Convertible
1947 62 Series Custom Project

bcroe

Step 1 is get your genernator off and apart,
to check for any obvious problem (like brushes).
One of the joys of old cars is learning to take
apart stuff that has been stuck together since
new. 

An excess amount of resources can be spent on a
problem, if first the cause is not found. 

Anything beyond repairing the original gen (or
direct swap), or the regulator, is going to be
orders of magnitude more difficult.  On the
other hand, if functioning original equipment
is inadequate, the car might need the upgrade.  Bruce Roe

Davidcamper

I replaced my generator a few months ago with a 6 volt alternator from 5th Ave Internet Garage. Doing so I was also able to eliminate the firewall mounted voltage regulator. It runs great, charges and the lights are brighter. For me, I would not go back to an outdated technology like a generator. But then again, my caddy is not a show caddy and I make changes under the hood that reduce my odds have having a breakdown but still keep the original engine and stay cost effective.

VooDoo

Quote from: Davidcamper on March 13, 2023, 07:50:41 PMI replaced my generator a few months ago with a 6 volt alternator from 5th Ave Internet Garage. Doing so I was also able to eliminate the firewall mounted voltage regulator. It runs great, charges and the lights are brighter. For me, I would not go back to an outdated technology like a generator. But then again, my caddy is not a show caddy and I make changes under the hood that reduce my odds have having a breakdown but still keep the original engine and stay cost effective.

The prices seem pretty reasonable. What year caddy did you put it in? And did you need to modify anything bracket wise to make it mount correctly
Andy Fulenwider
1937 75 Series Convertible
1947 62 Series Custom Project

Davidcamper

I installed it in my 51 Cadillac. Yes, I did have to use the bracket that fits a multitude of alternator widths. 5th avenue Carrie's it but I shopped around on the net and found it a lot cheaper. If you will notice the alternator with a black center stripe indicates 6 volt. With a red stripe 12 volts. Also, dont be fooled by 6 volt alternators made by others, as only 5th Ave 6 volt alternators have a proprietary internal workings. They are tried and true.

VooDoo

Quote from: Davidcamper on March 13, 2023, 09:51:04 PMI installed it in my 51 Cadillac. Yes, I did have to use the bracket that fits a multitude of alternator widths. 5th avenue Carrie's it but I shopped around on the net and found it a lot cheaper. If you will notice the alternator with a black center stripe indicates 6 volt. With a red stripe 12 volts. Also, dont be fooled by 6 volt alternators made by others, as only 5th Ave 6 volt alternators have a proprietary internal workings. They are tried and true.

Thanks for the info. I was looking at Generader I really like what they're doing but it's pretty pricey. About $850 but they build the alternator within the housing of the generator so from the outside you can't tell.
Andy Fulenwider
1937 75 Series Convertible
1947 62 Series Custom Project

Caddy Wizard

PowerGen is about $450 and looks like your original generator.  Fits on existing brackets.  Looks and works great.  If they are offering a version with the second post for an idiot light, get that version.

Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)

VooDoo

#14
Quote from: Caddy Wizard on March 14, 2023, 09:17:45 AMPowerGen is about $450 and looks like your original generator.  Fits on existing brackets.  Looks and works great.  If they are offering a version with the second post for an idiot light, get that version.

I call powergen yesterday and sent them some pics. This is the gems on my 47. Was just way easier to take better pics of this one. They appear to look the same anyways... This is what they told me..

 It appears in the photos the front bracket is not a 6-12 set up, and without the rear support, the bracket may fail. It appears to be a 1 inch belt. We only have 3/4 inch.


Andy Fulenwider
1937 75 Series Convertible
1947 62 Series Custom Project

Caddy Wizard

I misunderstood the original post.  I thought this was about a 49 Cadillac, not an earlier one.  NOt sure if the PowerGen will mount the same...
Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)

jackworstell

#16
Several years back we decided to put a 6V alternator on our 1937
Series 60.....with the 346 V8

We found that our options were sharply limited
because of the design of the front plate of the 346

The expensive semi-custom units were available
but we didn't want to spend that much money


The only solution we could find...at the time
....was to use a converted CS 121 alternator...these are somewhat smaller
than other alternators  and this makes a difference.
At  the time 6V  POSITIVE ground CS 121 units were available form
Howard Enterprises ( in Kansas as I recall )
Don't know if these converted CS 121 units are still available...

And even so...an adapter bracket ( "Becker" bracket) was required
( I have the drawing somewhere)

But first question...did the 1937 Series 75 use the 346ci V8 ?


Jack Worstell  jlwmaster2@aol.comwas  needed.  I have the drawings somewhere

VooDoo

P
Quote from: jackworstell on March 14, 2023, 07:20:44 PMSeveral years back we decided to put a 6V alternator on our 1937
Series 60.....with the 346 V8

We found that our options were sharply limited
because of the design of the front plate of the 346

The expensive semi-custom units were available
but we didn't want to spend that much money


The only solution we could find...at the time
....was to use a converted CS 121 alternator...these are somewhat smaller
than other alternators  and this makes a difference.
At  the time 6V  POSITIVE ground CS 121 units were available form
Howard Enterprises ( in Kansas as I recall )
Don't know if these converted CS 121 units are still available...

And even so...an adapter bracket ( "Becker" bracket) was required
( I have the drawing somewhere)

But first question...did the 1937 Series 75 use the 346ci V8 ?


Jack Worstell  jlwmaster2@aol.comwas  needed.  I have the drawings somewhere

Yes it is a 346 V8
Andy Fulenwider
1937 75 Series Convertible
1947 62 Series Custom Project