6 To12 Volt Conversion Question

[texas275]

My 53 B4B came to me with no wiring.  I mean every piece of wire was gone, broken, or chewed in half.  With that being said I am going with a 12 volt GM alternator set up.  I have built the bracket and put the alternator in.  I purchased a cheap set of guages for the time being, but will put the originals back in once I have them re-done.

 

I have searched the forums for exactly how the wiring should run, but have not found what I am looking for.  I have a crude drawing of how I believe it is supposed to be set up.  Could yall take a look at it and tell me if I am on the right track.  I am not worried about wiring anything up right now except the ignition switch, starter, battery, alternator, ampmeter, coil, and distributor.  I'm about ready to get thisthing started for the first time in 30 years.

wiring diagram.bmp

 

Thanks in advance for your help,  Tom

[Merle Coggins]

Looks good to me. You may want to add a charge indicator lamp between the ign. switch and the alternator excite circuit. Maybe it won't matter, but I'm used to seeing one there.

 

Merle

[Dave72dt]

Something to be aware of down the road is you may not be able to run the original ammeter with the alternator.  The alternator could put out more amps than the gauge can handle unless you're putting on one of the original 35 amp units.  Most are 55 or more in that design.

[Desotodav]

Here's a wire schematic link for you Tom... http://dodgepilothouseclub.org/know/wiring_harness/wiring.htm . There's a lot of great information in there.

[Merle Coggins]

A B4B should have a 50-0-50 ammeter. But the caution hold true if the alternator puts out more than that.

 

Merle

[Don Coatney]

Question is why would you need a high output alternator?

[texas275]

I don’t necessarily need a high output alt, but I decided to go with the modern 12 volt set up mostly for convenience and cost.  My truck is not near original or concourse correct, so I decided I would keep it mostly stock, with some more modern attachments.  (modern radio, electric fuel pump, electronic ignition in the future, maybe an electric fan, etc.)

 

I have restored several items in the past, but never had a place like this where I could get information and ideas.  The information and expertise here makes it a lot less stressful, and a lot more fun.   I really appreciate this site and all of your input and experience.

 

I finally found a radiator that will work, but I will have to fab some mounts, but I'm hoping I will get it to start this weekend.

 

Thanks, Tom

[Don Coatney]

I am running a GM single wire 12 volt negative ground alternator in my P-15. I do not know what the rated output is on this alternator. My biggest load is an electric cooling fan and this unit keeps up when the fan runs. I am using the original amp gauge with no issues. On initial start up I must race the engine to around 1200 RPM,s to excite the alternator. Once excited and charging it remains in the excited state until I shut the engine down.

[texas275]

Ok, new question. 

 

I wired it up and it starts and runs but it won’t shut off with the key.  I read that it needed a diode on the number 1 wire from the alternator.  I put one in and it still won’t shut off.  I have the wire from the starter/battery going to the battery side of the switch, and the rest of the wires got to the accessory side.  I know the alternator is keeping it running, and I know I have something hooked up wrong, but I don’t know what it is.

Any ideas?

Tom

[Don Coatney]

What all is connected to the accessary side of your switch? I suspect you have something back feeding.

 

[Dave72dt]

One wire  alt or two?  two wire has a keyed exciter wire.  Diode may be faulty or in backwards.  Getting the rpms below the alternater's kick-in range will help.  When converting tractors over, I'd use a switch with a seperate acc terminal  and wire the ign to IGN terminal and the exciter wire to the ACC term so it couldn't backfeed the ign

Edited April 18, 2013 by Dave72dt

[lugnut123]

The wire off your alt. Did you hook it to the pos side on your coil.  That's what the problem is. Hook that alt wire to the accsory side of the switch. I bet that will cure it. noel in nm

[texas275]

It has the main wire that goes to the starter then two more wires that come off of the side of the alternator.  Would that be a 3 wire?  Tried two different diodes but same result

 

The key switch is the Chinese model, with Batt, ign, and acc.  I don’t have anything on the ign post as I was assuming that was for a solenoid type starter.

 

So I need to wire my ignition (coil wire) to the ign post and leave the others on the acc post?

[texas275]

I have the number 1 wire off of the alt going to the key switch and the coil wire running from the same post on switch. So I guess it is like wiring it straight to the alternator.  So do I need to move my coil wire to the ign post?

[Merle Coggins]

yes

[Dave72dt]

So where is the third wire going to?

[Don Coatney]

yes

 

Yes again

[texas275]

The main wire comes off of the back of the alt to the battery/starter, the number one wire from the side goes back to the ignition, and the number 2 wire from the side connects to the one on the back of the alternator.

 

I assumed the ign side of the switch was only for a solenoid, and only had power while turning to the far right.  I will move the coil wire to the ign side of the switch when I get home.  I’ll let yall know if that does it.

[lugnut123]

The hot wire offf your alt the one that comes off the back of the alt. . hook it to the + pos on your battery or to the starter where the hot+ caable come from the batt.. The wire you plug in to your altrun it to your acc or to the + pos side of your coil. The plug in wire turns your alt on and off so it needs to be keyed. That third wire don't worry about it. It mite be a ground wire.

[Dave72dt]

The # 2 terminal can be left disconnected or attached to the BAT post on the alternater. It'll work either way.

[Don Coatney]

This is how I have my alternator wired.

 

[texas275]

That fixed it.  Moved the wire going to the coil to the ign post on the switch and works like it's supposed to. I knew I was missing something,  Thanks guys for your help.