News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

12V generator for flathead

Started by nixiebunny, May 17, 2018, 01:30:00 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

nixiebunny

I am staring at a 1987 Cavalier alternator and thinking about how it's not quite right for my 1940 LaSalle. It's the only newly-engineered thing that would be on the car.

Has anyone converted a 6V generator to 12V by installing the guts from a newer generator into an older housing, or swapped the end pieces, or whatever it takes to achieve 12Vness in the original mounting style?

Carl Fielding

Your 1940 LaSalle is a 6 volt car. What would be the reason for "12Vness"?  -  CC

Jim Miller

Dave - from earlier posts you have a 1942 346 in the car. Following folks on the forum for the last year has convinced me that unless there is a compelling reason to make a change, the original systems well maintained work quite well. And if there is an issue you can generally follow the shop manual because things are as the manual describes.
Jim Miller

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

wrench

1951 Series 62 Sedan
1969 Eldorado
1970 Eldorado (Triple Black w/power roof)
1958 Apache 3/4 ton 4x4
2005 F250
2014 FLHP
2014 SRX

bcroe

Quote from: nixiebunny
I am staring at a 1987 Cavalier alternator and thinking about how it's not quite right for my 1940 LaSalle. It's the only newly-engineered thing that would be on the car.
Has anyone converted a 6V generator to 12V by installing the guts from a newer generator into an older housing, or swapped the end pieces, or whatever it takes to achieve 12Vness in the original mounting style? 

Its not obvious what you are trying to achieve.  If everything in
the car is stock, why do you want to go to 12V?  And why change
from positive ground to negative ground, your ignition and some
gauges won't like that?  There are 12V generators which can be
set up for the polarity you want, why do you want an alternator? 
Bruce Roe

Steve Passmore

Dave, I'm not going to get into an argument on this forum about the pros and cons of 12-volt conversions so when you have recovered from all the negative remarks you have received regarding your original question PM me and get some unbiased advice.
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

bcroe

Quote from: nixiebunny
Has anyone converted a 6V generator to 12V by installing the guts from a newer generator into an older housing, or swapped the end pieces, or whatever it takes to achieve 12Vness in the original mounting style?

The short answer is you don't have to convert a generator, just use
a 12V generator and proper regulator.  Bruce Roe

Steve Passmore

That would be a perfect solution Bruce but sadly there are few 12-volt generators with the special front bracket to fit into a flathead, and the brackets do not interchange with the later generators. Sometimes one gets lucky and finds a War-time 12 volt but I have only ever seen one of these.
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

bcroe

Quote from: Steve Passmore on May 17, 2018, 12:13:52 PM
That would be a perfect solution Bruce but sadly there are few 12-volt generators with the special front bracket to fit into a flathead, and the brackets do not interchange with the later generators. Sometimes one gets lucky and finds a War-time 12 volt but I have only ever seen one of these. 

Yea, the military used higher voltages.  I would lay a 60 or so generator
next to your 40 gen, and figure out if indeed the internal parts would
interchange.  Need to be remagetized for positive ground.   Failing that,
note the wire gauge and number of turns on the armatures, and
relative resistance of the field windings.  That 6V generator might be
capable of 12V with the right reg (pos ground 12V).  Probably something
I should not recommend till trying it myself, with an output fuse.  Bruce Roe

jackworstell

Steve Passmore

Steve..I seem to remember a comment of yours to the effect that the 346 generator
dimensions are different than those of most generators...esp shorter length ???  So
finding    "on the shelf" 12 v generator parts to fit into a 346 generator to get a 12v unit looks iffy to me.

I know that there is an outfit that will take your 6v generator and convert it to 12v....so you don't have to worry about physical fit.   This as I recall is pushing $1000.
And there are 12 v  PG generators that are not exactly like 6v 346 generators that will ....I think...fit in physically ok.   Price pushing  $500     ( I think these are 6v  or  12v   and PG  or  NG )
These options have been discussed on this forum a number of times...a search will find them.

As Steve has pointed out a number of times....changing out a 6v 346 generator to some other
current producing device gets tricky because of the design of the front cover of a 346.   This is
hard to describe without having the the engine....or at least a photo...in front of you.

I don't want to get into the debate of   6v  vs   8v    vs   12v       and alternator vs   generator.
This has been done on this forum  many times.  But I do want to mention that CS 121 type alternators
are available in 6v or  12v    and    PG  or  NG.     The   CS 121 is smaller than most alternators
and will fit better.....but still with a "custom" bracket of some kind...... into the unusual 346 front plate


Dave...the best bet is to take Steve up on his offer and PM him...he will go thru options and pros and cons with you.

At the risk of prompting more discussion...we are changing our 1937 Buick over to 8v battery and
8v  NG alternator    I think that  8v   PG CS 121 units will be available in two months...if so
we will change our 1937 Cadillac series 60 over to 8v battery/8v alternator
And yes we realize the cons as well as the pros of doing this ( we cringe at the departure from
"original"    but we want more juice   spinning the starter faster and brighter lights)


Jack Worstell   jlwmaster@aol.com

Bobby B

Thank You Steve  ;).......
                  Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

bcroe

I suppose you need to be there.  It just looks like if that hose was moved,
there would be all kinds of room to put in an alternator mounting. 
Bruce Roe

Steve Passmore

Just as you say Bruce, the part you can't see is the problem. There is a specific distance between the fixing arms on the timing cover behind Bobby's alternator that a normal size alternator and it's bracket just will not fit in.
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

jackworstell

Bobby...your two photos above,,,,,,,I suppose this is a  CS 121 type alternator mounted in a
"Becker"   adapting bracket   ???

Jack Worstell

bcroe

Is the issue keeping the pulley center in the exact same  location? 
I might raise it 1/2 inch or more and make a new bracket. 
Bruce Roe

nixiebunny

Thanks for all the thoughtful responses. It sounds like there is no easy 12V generator solution for the flathead. I understand that there are reasons for retaining 6V for old cars, but I am not trying to keep this car 100% as if it just came out of a factory. I want it to be relatively easy to maintain, yet in the spirit of using all GM parts.

My goal was to have the engine look more original, yet use 12V because everything these days is 12V. I'm an electrical engineer so I tend to stick extra goodies on my cars' electrical systems.

We are going to install a CS121 for an '87 Cavalier, 85A. My brother and I both have a lot of experience making things fit, so I think we'll be able to do the brackets. I like the black paint idea - it hides the alternator and makes it look a bit more old-fashioned.


Bobby B

Quote from: bcroe on May 18, 2018, 10:06:20 AM
Is the issue keeping the pulley center in the exact same  location? 
I might raise it 1/2 inch or more and make a new bracket. 

Bruce,
The center really doesn't matter. It's more the diameter to fit in-between the "V" of the Timing cover. Making a bracket is easy. Getting it to fit in the stock location involves a little bit of thought process and the bracket that Steve has machined. It's not worth your time fabricating one, and it doesn't look the same. The "Gener-nator" is just ridiculously overpriced. Most of it's under the factory air cleaner anyway, so I don't see why using an Alternator as an upgrade is such a big deal. Converting to 12V was the smartest thing I ever did to the car.
                                                                                        hobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

nixiebunny

We installed the CS121 alternator in the LaSalle. Since it only cost $42, we decided to make the job easier by modifying the front of the alternator to bolt to the right-side generator mounting ear. This involved cutting off the 2" thick ear and milling it to 0.75" thick. That aligns the pulleys correctly.
Then we used most of an aftermarket Chevy alternator bracket to mount the left upper ear, with a 0.75" spacer from the left generator ear. This mounts the alternator solidly with some adjustment range.
It seems to work.

Bobby B

Quote from: nixiebunny on May 20, 2018, 12:15:03 AM
We installed the CS121 alternator in the LaSalle. Since it only cost $42, we decided to make the job easier by modifying the front of the alternator to bolt to the right-side generator mounting ear. This involved cutting off the 2" thick ear and milling it to 0.75" thick. That aligns the pulleys correctly.
Then we used most of an aftermarket Chevy alternator bracket to mount the left upper ear, with a 0.75" spacer from the left generator ear. This mounts the alternator solidly with some adjustment range.

Nice Job! Just out of curiosity, how'd you get the generator pulley to stay on the interference fit CS121 shaft?
                                                                                                  Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

bcroe

Quote from: nixiebunny
We installed the CS121 alternator in the LaSalle.

This involved cutting off the 2" thick ear and milling it to 0.75" thick. That aligns the pulleys correctly.

Then we used most of an aftermarket Chevy alternator bracket 

Nice work.  Bruce Roe