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I started up my M 37 and it was not charging. I drove it a week ago it was fine charging 27.2 volts. It has a single wire Ac Delco alternator. It did this before after I had it looked at at an alternator shop. I pulled it apart and there was grease on the brushes. I cleaned the grease off and removed the excess from the bearing, as well as repositioned the brushes so they made better contact on the commutator. The commutator was not smooth and there was wear on the armatuer. It just looked worn out. Here is my question where do I find a 24 volt Alternator. Can I buy a 12 volt alternator and switch to a 24 volt internal Regulator. Currently it is internally regulated and also runs through the old Autolite Regulator. 21 volts was the reading at the alternator this morning. It was 33 degrees out.
Thank You
Rich Szklany

We can furnish a 1-wire Delco-Remy alternator in 24 volts for around $150. You should not have it wired through the old regulator as it is internally regulated, this situation may well be causing your issues. To convert a 12-volt unit to 24-volt, the armature must also be wound for 24-volts. Much better off $$ wise to obtain a 24-volt unit than to convert a 12-volt.

http://cgi.ebay.com/ebaymotors/New-Alte ... iesQ5fGear

http://cgi.ebay.com/ebaymotors/New-Alte ... iesQ5fGear

http://cgi.ebay.com/ebaymotors/Delco-Re ... ccessories

Charles and Chunk
I will pull the old voltage regulator before I replace the alternator.
Thankyou for the information it is just what I needed.
Rich Szklany

I have a question. The one wire Alternator sounds like a good up grade but after disconnecting the regulator what happens to the dash's charge gauge? And how easy is the install? Thanks much

Wayne64 wrote:I have a question. The one wire Alternator sounds like a good up grade but after disconnecting the regulator what happens to the dash's charge gauge? And how easy is the install? Thanks much

About as easy to install as it gets. As far as power input to the instrument panel, just run a lead from the starter switch battery positive post to the circuit breakers, all will function as usual.

You should also swap the ammeter out for a volt meter. Be sure to put the volt meter on a switched power source (one that has no power when the master switch is off.).

Rich, If it helps.... before I upgraded to the delco 24 volt 10si alternator,all I would get out of my truck was a voltage reulator that sounded like a pinball machine,and a gauge that would read in the yellow. No matter how much I cleaned the points in the regulator, grounding points on the truck,battery cables,battery terminals,etc, nothing would help. The batteries never seemed to have a heathy output even when the system was operating properly. Always cranked slow no matter what. After I installed the alternator,all those problems dissappeared! A few people on this board said a one wire alternator won't work good,don't operate as well as a three wire alternator set up,hard to get parts for,etc,etc. Pure bunk if you ask me. This set up works FLAWLESSLY!!!! We just had -15 below weather here in fernley,and my "M" started no with no problems what so ever without a fuel primer. Just use of the choke. Batteries never get "cooked",or under charged. Headlights are brighter,and engine seems to run smoother. Best part is that I can put it back to bone stock configuration with no problems. I kept my old parts just in case,but will probably never use them. Go with the "one wire" alternator. You'll never look back. One other thing....They make a pulley that bolts on that fits the M37's wide belt too! Just for the record,The generator pulley shaft size is the same size as the alternator shaft size. All I did is machine down the over all length of my generator pulley and mounted it to the alternator. If you have any questions let me know.

Any quality auto electrical shop can provide you with the correct width pulley for your alternator. You can use the pulley off your generator but it will turn the alternator at the incorrect ratio. One wire vs 3 wire is not very important. If the one wire alternator's internal regulator fails you have to remove the alternator. If the 3 wire alternator's external regulator fails you only have to fool with the regulator. It's all up to you. Either is a big step forward from the original 25 amp generator and mechanical regulator.

I have run the 25 amp mechanically regulated generator for years and they serve well as long as you don't try to run 40 or 50 amps worth of accessories. It takes a little more then contact cleaning to keep the old system going. Springs soften and resistance increases with age in coils and resistors which force you to make occasional adjustments to the old regulator. They are delicate adjustments which if done incorrectly will make things worse.

Our changing throw away society is rapidly changing how we perceive old reliable equipment and how much time we are willing to expend on it.

When selecting a new alternator be sure to determine the maximum load your truck's equipment will place on it. Try to keep this load at about 80% or less of the new alternator's capacity. Unless you are trying to keep the dash perfectly correct I would also replace that dash amp meter or color coded volt meter with a good quality analog or digital volt meter that fits the same hole.

[quote="cuz"] You can use the pulley off your generator but it will turn the alternator at the incorrect ratio.

Really? What would you consider to be the correct ratio? When I start my truck,I don't need to rev it up to spike the alternator into charging. What is the correct "ratio" you speak of? What is the stock ratio? My set up works flawlessly.

We have used 1 wire Delco's as replacements for years, never an issue. Any one with any general electro-mechanical knowledge can rebuild one in just a few minutes. All parts available at NAPA, so dealing with the internal regulator if the need arose would be no issue, although we have not had the first one to give any problems of any kind. I would chose the single wire set up every time. We always used the original belt pulley from the old generator also, turns the unit fast enough at idle to get low rpm charging, which you will never get with the 25 amp generator. In my opinion, this modestly priced upgrade offers a huge bang for the buck.

I'm still waiting for the "ratio"

Chunk wrote:I'm still waiting for the "ratio"

I may be totally off base here but looking for a ratio in this setup is like looking for oranges in an apple orchard. Changing pulley sizes between the same kind of unit will yield a ratio difference. But here we are talking oldskool generator to a current standard alternator. Now for increased RPM of any unit you reduce the pulley size at a given RPM of the engine. To reduce both the alternator RPM (and out put of the alternator) you increase the pulley OD at the same engine RPM.

Here is why I prefer three wire over one wire
http://www.madelectrical.com/electrical ... wire.shtml

J.B.

I'll stick with my "one wire" thanks.