How to wire in a Delco 10si 1 wire alternator on a M37

[TJPR]

Hi All, Hopefully someone can give me guidance in how to run wiring useing a 24 volt Delco 10si one wire alternator. The original 100 amp alternator on my 53 M37 stopped chargeing properly. I have read articales saying to run the power wire to the battery side of the starter. Another says to run the power wire to the ampmeter and from the ampmeter to the battery side post on the starter (I assume they mean the voltmeter in the gauge panel). On the wiring diagram the #10 supplies power to the gauges and accessories I would think power has to run to that also. I have the alternator braket built and ready to mount it and do the wiring.

If anyone can help me with this it would be greatly appreciated. Im not great with wiring and would like to get it right the first time.

 

[pjwest03]

http://www.steelsoldiers.com/showthread.php?158316-M37-wiring-diagram

Original equipment was a generator. You can run the one wire to the battery post on the starter or directly to the battery. If you don't have ammeter (some have a voltmeter some have an ammeter) no worries. If you have an ammeter that would require a shunt resistor and is a bit more complicated. Ammeter was driven from the old generator regulator.

Wire #10 will need to go to a source of constant power could be picked up at the alternator, starter, or battery terminal. I myself would add a fuse or circuit breaker to the new alternator line and to the #10 wire for safety to protect the wire and avoid fires.

 

[TJPR]

Thanks pjwest03 for the reply. My M37 was apparently a radio truck the Alt/Gen is hugh and has a 4belt pulley on it. I have read that this is actually a alternator. There is a rectifier behind the grill there are large treaded tubes that contain the wires, 1 runs from the alt to the rectifier another from the rectifier to a large voltage regulator. There are 3 wires out of the regulator, 1 cable is grounded to the engine block, 1 cable goes to the battery side of the starter and 1 large wire runs to the dash area which I assume is the #10 wire. Maybe this is more info than you need? The gauge I have has a band in it left side is red center is yellow and right side is green, it says Battery Generator on it. Do you know if this is a voltmeter or a ammeter. Or is there a way to tell. If its a ammeter how would you hook up a shunt resistor.

Thanks again

 

[pjwest03]

OK. The rectifier will no longer be needed. The regulator will no longer be needed. Generally the ammeter was on wires 8 and 9 on the regulator. If the OE was indeed an alternator that gauge may be a volt meter. From the face description it sounds like an M series voltmeter. There are a number of variations. It may have the part number on the face.

I would say the one wire on the alternator should go to the battery side of the starter and the #10 wire to the same location. That should be it. For me, I would use a 4ga wire from the alternator.

When ever I convert things. I usually keep the old parts to pass on to the next owner if they want to return it to stock. I've put a fair number of 10si alternators on tractors and other bits of machinery.

 

[TJPR]

Great Thanks for the help with this. I am keeping the old parts. I may have them checked out to see what the problem is with them. For now I just want to get the old M37 road worthy. I will wire it as you explained. I'll let you know how it goes.

 

[TJPR]

pjwest03, I have one more question if you don't mind. What size fuse or brecker would you recommend on the cable from the alt to the battery connection on and starter, and what size for the wire from the battery connect on the starter to the #10 wire. The alternator I have is a 40 amp.

 

[pjwest03]

OK, for a 40 amp alternator I would go with 125% so a 50 amp fuse. You could probably go with 6ga or 8ga wire for a 40a set up. Although no wire is ever too big. I would look @ 20 - 30 amp for the #10 wire. Maxi fuses are a good available choice for a 50 amp fuse. And me being me, I would use maxi fuses for both to be consistent. The holders are available with either 6ga or 8ga leads. Maxi fuse holders are also available in marine grade from Blue Sea.

 

[TJPR]

I just wanted to thank pjwest03 again for his help. I wired the new alternator in, one wire from the alternator to the battery connection on the starter and one from the battery connection on the starter to the #10 wire that goes into the dash area. I also grounded the alternator to the engine block. I do have a voltmeter. Everything is working as it should. This was a easy conversion and I would recomend it.

 

[pjwest03]

Happy to be of service.

 

[jedawson1]

This is an old thread, but can anyone help confirm. Am I really seeing these Delco 24 volt alternators for about $80?

My M37 generator is bad and fried my regulator. I am liking the cost of the Delco 10si single wire over a new generator and regulator.

Advice, thoughts?

 

[pjwest03]

Yes. $80-100 range for gasoline applications. A bit more if you want higher output.

Diesel low rpm versions tend to be more like $130-150.

The 10 si alternators were used for decades. Very common. Still popular because they are easy to use, easy to rebuild, and easy to modify.

The only difference between 12v and 24v ones is the regulator. Basically a $15 dollar part.

There's a bewildering quantity of part numbers but, thats primarily how the housing is clocked and the pulley options.

You may need to reclock your specific alternator to get the bolt holes where you need them. Just take the bolts out a realign the halves. Try not to pull the halves apart too far. Not a big deal if you do. Just more fiddling to get the brushes right if you separate them.

 

[M-37Bruce]

I would add a ceramic ballast as well in line with the hot wire, cheap and a good investment. Mine is in line with the ignition.

 

[jedawson1]

Ordered a Delco 10si Alternator today for $140 at Napa, should arrive by noon tomorrow. Now I need to inventory my wire and see if I have fuse large enough. Thanks for the advice.