Jump to content

1955 Buick - Generator to alternator conversion wiring question


bigaudioal

Recommended Posts

Let's see if ANYONE can answer this question. On the voltage regulator in the 1955 Buick (Century 4-door hardtop, series 63 with 322 v-8, dynaflow tranny) there are three terminals. The one in the middle has a white wire on it that comes from the generator. That white wire has a smaller green wire attached to it that runs from that same terminal to the starter relay just below the voltage regulator on the inner fender. I am assuming this is part of the starter cut-off circuit so the starter does not engage when stepping on the pedal after the engine is running. May not be correct, but that's my assumption.

Here's my question and where it gets tricky. I had my generator converter to an alternator. Cool part is, according to the instructions and diagram that guy who did the conversion sent me, I do not have to alter the stock wiring EXCEPT for moving that white wire that comes from the generator from the middle voltage regulator terminal, to the left "B" (battery) terminal on the voltage regulator. Wired this way the alternator charges the battery (I tested while car running and it works. Attached in the stock position battery not charging, attached to the "B" terminal, battery charges.)

So, does that little green wire from the starter relay come with the white one, or does it stay on the middle terminal all by itself? Wish I knew more about how the circuit works. Will this change make the cut off circuit not work? If so, how do I get around this? Anyone know anything about this???? Thanks.

-Al

Link to comment
Share on other sites

Al, that green wire, in the original configuration, is the ground for the starter relay. Internally grounded in the generator UNTIL it begins to charge, then is an open circuit, therefore keeping the relay from working. It can't hook to the "bat" terminal as this would not ground the relay, therefore keeping it from working. Does the starter work with it hooked to the middle. ??

Ben

Link to comment
Share on other sites

Oh, that makes sense! Thanks for the reply. I have not messed with it yet b/c did not want try anything until I knew what I was dealing with. I will move the white wire to the "Bat" terminal (thereby allowing alternator to work and charge battery) and try keeping the green wire connecter to the middle terminal by itself and see if starter works to start and then does not engage once engine is running.

Any ideas if that test does not work (either starter will not come on, or tries to engage while engine is running)?

Thanks for any advice. I am not great with electrical work and need all the help I can get.

Link to comment
Share on other sites

  • 1 year later...

I know im resurrecting an old thread, but I'm looking to go alternator on my car and ran across this idea...

That green wire, your exactly right it is a safety for the starter. when the generator is not rotating it earth's through the generator creating the starter circuit once it cranks up to speed it then becomes 6v and balances the circuit on the starter so the coil drops out.

so to make it all work ive just grounded mine and that's that. The downside of this is you loose the second safety feature it once provided. So having a bit of a think I wired it up to an oil pressure switch and when it senses oil pressure it breaks the earth disabling the starter solenoid.

check out my wiring diagram bit different to yours but should work the same.

http://www.teambuick.com/forums/showthread.php?22750-49-Roadmaster-6V-and-12v-system-combined

  • Like 1
Link to comment
Share on other sites

You might want to try hooking the green wire to the field terminal of the alternator and see if it works. Field is grounded when not turning, after running becomes close to battery voltage, therefore starter relay will not be able to energize. A possible problem might be that the field wiring would feed back through starter relay coil when alternator is running. A simple diode would take care of that.

  • Like 1
Link to comment
Share on other sites

  • 1 year later...
Guest 55buickbeast

hello im currently looking into the same conversion and was wondering which alternator was used on the 322 nailhead? thanks..

Link to comment
Share on other sites

Oil switch is no good because it means as soon as you get oil pressure, the starter kicks out

 

If you use an alternator with a warning light circuit in it (has exciter diodes), that should work (I havnt done it)

 

The warning light circuit works by sending power via a light to the warning light terminal of the alternator to excite the alternator

 

Once the alternator is charging, it then sends a power back up the warning light wire, so 2 positives cancel out the light

 

Same thing should work using the starter relay coil in place of the warning light

 

Mick

  • Like 1
Link to comment
Share on other sites

The exciter diodes are internal to the alternator, so, no extra diodes or switches are required

 

Is that what you meant?

 

Another thing to remember if your car has an ammeter fitted is to not go to crazy with the current output of the alternator you choose

 

The ammeter was designed for the size of the original charging system and you can easily burn them out with excessive current flow

 

It can be bypassed (and really, its better to run the battery + wire for the new alternator directly to the battery (via some form of fusing, I use fusable links on old cars, more period correct)) and a volt meter fitted somewhere, but I have to admit that I hate knowing something in my car doesnt work

 

Mick

Link to comment
Share on other sites

Mick, I have seen all kinds of theories- some of which require the warning light circuit. My experience is with a single wire Powermaster that excites once it hits a certain RPM. I am going entirely through the original system except that I did something at the voltage regulator. I believe that is explained earlier in this thread. If not I can take pics or explain while I am looking at the car in my garage.

Link to comment
Share on other sites

Go to post #34 by Bhambulldog on the link supplied by old-tank and you can see the solution to this problem. Basically the ISO relay contacts provide a path to ground when the alternator is not charging. Once the alternator begins charging the relay energizes and opens the contacts and then there is no ground connection so the original Buick starter relay will not send voltage to the starter solenoid.

Joe,

Link to comment
Share on other sites

I was a bit irritated when we converted our '56 to an alternator, because I thought I knew what we were getting but it didn't play out that way.

 

I knew the alternator in my '83 Chevy would do nicely (10-SI), so that's what I asked for at the parts store, but I don't think that's exactly what I got.  The installation was fairly simple as I used the existing wiring for a clean, factory appearance and I stowed the wire we weren't using in case someone wanted to go back to the generator (or more realistically, dad decides the look of a modern alternator bugs him enough to by an alternator that looks like a generator).

 

I put the idiot light in one of the ash trays.  I didn't really need it because we have an ammeter, but the alternator won't work without it and I had to put it somewhere.  I think one of these days I'll run it as an ammeter light so the gauge glows red if there's a charging fail.  For some odd reason, it acts like a one-wire alternator in that I have to goose it after starting to get the alternator to cut-in.  Why does a 3-wire have an RPM cut-in?  I donno.  The one in my Chevy doesn't do that, but whatever.

 

As far as burning out an ammeter goes, if you aren't loading up the system beyond the original intent, you'll be fine.  My solid state amp inside an old radio cab draws much less power than a tubeset, and the Garmin pulls way less than a cigar lighter element.  Just because the alternator is capable of 70 amps, it doesn't mean we are putting any more current through the system than before.  An ammeter is just a volt meter across a calibrated shunt.  If you are concerned about frying the shunt, just put a 30 amp fuse or breaker on the alternator's bat terminal and you are covered.

 

I will say that it was really nice to go for a cruise last weekend, and with the tunes, GPS, and headlights on, the ammeter was still half-way up the green while idling at a red light...

Edited by SpecialEducation (see edit history)
Link to comment
Share on other sites

The 10si alternator is a pretty agricultural alternator, the air gap  between the rotor and stator can vary quite a lot

 

The closer the tolerance, the quicker it will kick off and the better it will charge, so you may have got a "loose" alternator.

 

That said, the other thing is your pulleys, the crank pulley for a generator car is generally smaller than one that had/has an alternator

 

The generator is not that good at handling high rpm (windings fly apart), so they kept the crank pulley as small as possible

 

The alternator is much better at handling high rpm, so a larger pulley was used, which then, means a later car (with the larger crank pulley) does not need the engine revved a bit to kick the alternator off

 

Your idea of a red light in the ammeter is a good one, but a 30 amp fuse in the charge wire is not, the main wire (B+) for the alternator must be fused to at least alternator max current capacity + 20% or you will be continually replacing the fuse

 

Obviously, the B+ wire must also be able to handle the current as well (this includes the ammeter or shunt if it is wired in), this is why if your not modifying the car much (things like GPS ect draw almost nothing, but some stereos can be major power suckers) its possible to fit a low capacity alternator (I have a 55 amp one on my 60 dodge) without changing much at all

 

Unless your running a big stereo, thermo fans ect, you shouldn't need to go bigger than that, but if your making your old car a modern car, you need to upgrade to what a modern car has

 

Mick

Link to comment
Share on other sites

The 10si alternator is a pretty agricultural alternator, the air gap  between the rotor and stator can vary quite a lot

 

The closer the tolerance, the quicker it will kick off and the better it will charge, so you may have got a "loose" alternator.

 

That said, the other thing is your pulleys, the crank pulley for a generator car is generally smaller than one that had/has an alternator

 

The generator is not that good at handling high rpm (windings fly apart), so they kept the crank pulley as small as possible

 

The alternator is much better at handling high rpm, so a larger pulley was used, which then, means a later car (with the larger crank pulley) does not need the engine revved a bit to kick the alternator off

 

Your idea of a red light in the ammeter is a good one, but a 30 amp fuse in the charge wire is not, the main wire (B+) for the alternator must be fused to at least alternator max current capacity + 20% or you will be continually replacing the fuse

 

Obviously, the B+ wire must also be able to handle the current as well (this includes the ammeter or shunt if it is wired in), this is why if your not modifying the car much (things like GPS ect draw almost nothing, but some stereos can be major power suckers) its possible to fit a low capacity alternator (I have a 55 amp one on my 60 dodge) without changing much at all

 

Unless your running a big stereo, thermo fans ect, you shouldn't need to go bigger than that, but if your making your old car a modern car, you need to upgrade to what a modern car has

 

Mick

Your pulley size explanation is backwards:  the smaller the generator or alternator pulley the faster it will spin.

  • Like 1
Link to comment
Share on other sites

Your pulley size explanation is backwards:  the smaller the generator or alternator pulley the faster it will spin.

You are correct that a smaller alternator pulley will spin the alternator faster, but I was talking crank pulley, so smaller crank pulley will spin it slower

 

Mick

Link to comment
Share on other sites

You are correct, you did say crank pulley.  But for this discussion of 1955 Buick there was never any difference in crank or generator pulley size (later nailheads had just before the change to alternator a 45amp generator with a smaller pulley was used).  And since these are not race cars, tolerance to high rpm is not a factor.

This discussion has lots of theories about what should work, but no detailed explanation of an actual installation that worked to more efficiently charge and also retain the accelerator start function.

Link to comment
Share on other sites

Oil switch is no good because it means as soon as you get oil pressure, the starter kicks out

 

If you use an alternator with a warning light circuit in it (has exciter diodes), that should work (I havnt done it)

 

The warning light circuit works by sending power via a light to the warning light terminal of the alternator to excite the alternator

 

Once the alternator is charging, it then sends a power back up the warning light wire, so 2 positives cancel out the light

 

Same thing should work using the starter relay coil in place of the warning light

 

Mick

I am a Buick newbie, so specific fitments are unknown to me

 

What I was explaining though, was why an engine needed to be revved to "kick off" an alternator on a car that was originally fitted with a generator

 

I did explain about using an alternator with a warning light circuit built into it as a possible remedy to the start relay problem (read above)

 

I would prove this with my own car if I could, but at some time in its life, things got changed around a little and the throttle start system is no longer there

 

I have thought about getting it all back (I think its cool, just like the push button trans on my dodge), but I am more concerned with getting the car on the road first

 

I am an auto electrician, so, if I had a specific wiring schematic, I could easily answer this better (If how I think it works is wrong)

 

I have a cd version of the chassis and body workshop manuals, but the drawings are sort of washed out and the detail has been lost

 

Mick

Link to comment
Share on other sites

Mick, I do appreciate your contribution and expertise, and hope you will continue to offer your help.  I have not done this swap either otherwise the details would be in the tech tips page of my website (http://www.buickrestorer.com/lowtechtips.html ).  I am sure someone has successfully done the change over, but all have neglected to share. :(

Willie

Link to comment
Share on other sites

The only problem I see with how I think it should work is that the positive supply to the relay (that then goes to the alternator to excite it) could get cut off (by the operator) if the engine fired quickly, causing the alternator to not excite

 

If this happened, I think the switch on the throttle would stop the starter re energizing while you gave it a rev to kick the alternator off

 

But as I said, I havnt done it and mines all gone from my car to play with it :)

Link to comment
Share on other sites

Your pulley size explanation is backwards:  the smaller the generator or alternator pulley the faster it will spin.

 

The pulley that is on the alternator in the '56 is exactly the same as the pulley on the alternator in the '83, and the crank pulley is bigger in the Buick, so this alternator is spinning faster at equal engine revs.  I don't have a tach on either engine, but I have little doubt that the Buick idle is higher than the Chevy.

 

Whether this alternator is 'loose' or someone just put the wrong control circuit in it, it's obviously different internally from the factory alternator on the '83.  Regardless, it was one of the best $45 mods we ever did.

Link to comment
Share on other sites

Another thing that can cause an alternator that uses a warning light to excite is if the wattage of the warning light is to small

 

If the light you have in the ashtray is one of those small pilot lights with a small wedge bulb in it (1/4 W), that can cause it

 

On the older alternators, the warning light bulb was the same as your instrument illumination bulbs (3 to 5 W)

 

I wouldnt worry to much about it myself, but if it bothers you and you have the small warning light, give the 5 watt one a try

 

You are right about the regulator as well, I have had alternators kick off at differing revs with different makes of regulator, but the difference is not usually very much

 

Mick

Link to comment
Share on other sites

  • 10 months later...
On 10/18/2015 at 6:17 PM, buick5563 said:

I have done this, but injured my back so haven't been out to the garage to take pics.

I will do so ASAP dangit:)

I am constantly digging up old stuff...  As I start to dig into my cars though I want to go this road again and was wondering if you ever got those pics Mike?

Link to comment
Share on other sites

Forgot.

There are a bunch of threads on the forum and on the internet that I read before starting this project. Originally, I installed a one wire PowerMaster (the kind that looks like a generator). It only was putting out around 12 volts with stereo, AC, iPods charging, gps (my speedo) and any other items I randomly selected to run...lights or electric wiper, etc. This worked fine, but I got to thinking it would be a pain to have to make a change in the road. Do I carry a generator and have to rewire, or an alternator that wouldn't fit the original bracket? Buying an additional $350-400 spare seemed silly. I also wanted to try and figure out how to run a second belt on my compressor, so I bought a single wire, two belt alternator. This wiring works for either alternator. 

Remove green ground wire from GEN terminal on Voltage regulator (from starter relay). Ground it. I went to the starter relay mounting screw. Tape back the ARM and FIELD wires at the generator. 

That's it. I didn't install a diode or extra bulb or brake light switch. I personally have never had the starter engage, which is what people have claimed might happen. I do know this is a possibility, but it has not happened in the three years I have been driving this car across country with an alternator. 

The new alternator puts out a consistent 13.6-14 volts depending on what is turned on. I don't remember the amps.

BTW, my AC was fine with the stock generator, but I wanted to be able to consider adding other accessories, which is why I changed it over.

Secondly. The wires in the regulator pic appears to be burnt. It is just crud. 

image.jpeg

image.jpeg

Edited by buick5563
Punctuation (see edit history)
Link to comment
Share on other sites

14 minutes ago, Airy Cat said:

I have the original generator in my 1955 Buick, 64,000 miles and no problems.

 

I run a generator in my Special with no problems either. I also ran it in my wagon with the underdash AC for several years with only minor issues. I don't like people who discard old tech just cuz it is old tech.

With that said, my wagon is a test bed for newer ideas and like I said, it is running a lot of extras that Buick never thought would exist. The cost of the alternator conversion is more expensive than a rebuilt generator, although the voltage regulator prices have crept up to offset that price difference. 

Edited by buick5563 (see edit history)
Link to comment
Share on other sites

When you compare numbers, the cost to install an alternator is dwarfed by buying a new voltage regulator by $20. If your voltage regulator fries, then you have other issues within the generator that may also need to be looked at and a rebuild can run up to almost $100 in some cases. Alternators are also solid state voltage regulation, so there's no fear of burning points out. Lastly, there are many models ranging from the stock 30 amps all the way up to 120 amps, which broadens what you can put on the car and feel safe running (electric radiator fan, solid state ignition system, EFI, modern AC, sound system).

 

I tried the alternator conversion, worked really well, except I used a Mopar alternator (they flow/look better than a GM, but mount differently - where I screwed up). The Mopar alternator is triggered through the amp meter in the dash, so keeping the wiring the same meant I could do without a dummy light. I eventually removed it, though, because it didn't look right sitting there and the custom bracket to mount it was flimsy - not in construction, but the fact there there were two flex points to mount instead of one led to some very interesting scenarios. I had also wired it into the starter relay from the 6v field terminals and my starter relay welded shut and blew my starter, so I removed the whole system and went back to stock...

 

If I were to do an alternator conversion again, I would spend the money on the Powermaster alternator. Some units come with a field "lamp" terminal, which gives off 6V when charging to use as a ground for the starter relay. Of course the issue with one wire alternators is that you have to put your foot into them to get them to charge, and the old Buicks are turned over by putting your foot into it. Buick5563 has never had an issue, so it's probably nothing to worry about. Curious to know at what RPM they kick in at, though.

 

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...