I have seen a lot of discussion regarding upgrading the electrical system using a 12 volt alternator but very little regarding using a 6 volt alternator. My truck will be stock (still positive ground, 6 volt right now) when I finish but my generator needs to be re-built. It seems to me like installing a 6 volt alternator (maybe from Fifth Avenue?) instead of rebuilding the generator would be a good alternative (although not original) since I would not have to reduce voltage to instrument panel, heater, radio, ... I don't plan on adding any after market equipment that would require 12 volts. Any comments on this idea? Thanks

 

I know nothing of 6 volt systems. My 56 came as a 12 volt.

That said....how can you go wrong??? 6 volt is still 6 volt.

I don't see the difference in a generator vs. an alternator. My feeble mind says that sounds fine. (This is a test...isn't it?)

If I'm wrong.....never mind.

 

I have an alternator from 5th Avenue that I've been very happy with. One thing though, you will have to convert your system from positive to negative ground (which is fairly easy). Also, I've seen some places selling alternators made up to look like generators if you want to stay with the old-school look.

 

It's kind of a strange combination of new and old. I can't think of any reason to stay 6v and use an alternator. There will be wiring mods for an alternator anyway, so it is not only going to look different, there will be other mods from stock. It's almost the same amount of work and mods to change to 12v and makes everything easier and better, IMHO. The wipers are the tough one (if they are electric), gauges and wiring mods are easy. Heater fans are a little tougher. But 6v is a proven system, too.

 

A six volt alternator in a 5th Avenue? I don't think there is such a thing. The only six volt alternators I'm aware of are aftermarket. If you're going to all the trouble of converting to an alternator you might as well go 12V...

Vern

 

I took the plunge and converted to twelve. The PO had already partially done the deed when he swapped the motor out, and what wiring was there was in bad shape.

HOWEVER, if you want to go with a 6v system, I'd suggest rebuilding the generator (not that expensive), and simply keeping stock stock. Going with an alternator puts you on an entirely different power system, and will require some modifications in order to work properly.

Auto makers switched to 12v systems with the advent of power options: ie seats, windows, A/C. 12vs, quite obviously is twice as powerful as 6v, and could handle the load and still maintain lights, etc. If you aren't adding any power options to your truck, then you don't need to convert to 12v.

Alternators change the power supply from a Direct Current system (DC), to an Alternating Current (AC). This requires a negative ground system, as well as a voltage regulator in order to prevent the pulsing effect that the AC has on lights, blowers, guages, etc. In order to make these changes, your truck is going to look far from stock, and you really are going to be doing about 3/4 of the work it takes to switch to 12v.

So, in the long run: If you're staying 6v, keep the generator. If you're going alternator, go 12v as well, and decide to build a non-stock truck.

My 2 cents.

 

I too say stay with the 6v generator. You will save the fabrication hassle and there will not need to be any rewiring. Jag

 

GNW/Vern -- he meant he bought it from 5th Ave Auto Parts (I assume??)

The big question in my mind would be (as far as Alternator Vs Generator/Stock); what condition is the wiring system in? If you still have the stock fabric-covered original wiring, I can't believe it's in any kind of good shape. If you have to re-wire anyway, I would for sure go 12v unless you're going for a Concours 100 pt show truck.

 

I bought a 12V alternator and bracket from Fifth Avenue but I couldn't recommend them. First he sent me the wrong bracket. Then once I got it going the alternator boiled battery acid all over my fresh restoration due to a faulty regulator. If you go 12V I would check Ebay for the alternator bracket and just buy an alternator locally.

On the other hand, I have read Fifth Avenue's literature touting the benefits of their 6V alternator vs. a stock generator. According to them a stock alternator doesn't have the capability to keep up if there is much draw at all but unfortunately I can't tell you if the Fifth Avenue 6V alternator is a real improvement or not.

Going 12V really isn't too difficult and your wiring will easily handle it since the amperage will be cut in half. I just installed 12V bulbs and "Runtz" voltage reducers on the oil, temp, and fuel guages, and put a resistor on the blower circuit. Three years later and everything still works great.

Good luck with whatever you decide to do.

 

Thanks for all the opinions. The reference to a 6 volt alternator was to Fifth Avenue Garage, fifthaveinternetgarage on the internet (http://fifthaveinternetgarage.com/index.html). Their information provides good reading but I don't know how much of it to believe. As for the other comments, I will have to rewire the entire truck no matter which alternative I choose so that is not really an issue either way. The estimate to rebuild my generator was $125.00 and that is why I was looking at the 6 volt alternator as a way to get around buying new bulbs, voltage reducers, and resisters, .... The reason I was considering going to the alternator from a generator is the quicker charging at lower engine speeds since I won't have the opportunity to drive the truck any distance more than once a week at most.

I have seen the references to the alternator built to look like a generator but have never actually had anyone tell me who does this. It sounds like it could be an expensive custom modification.

I know the decision is mine to make but I am reading and asking all I can. Is $125.00 to rebuild the generator higher than normal? The armature is not working so I know that would probably be a large part of the cost.

This forum is great. It is like reading a good book but I get to help write the chapters and shape them into whatever I want. You can't beat that! Thanks for the help.

 

Oops...my bad. I've never heard of 5th Ave Auto Parts...

Vern

 

I have seen alternators built into original generator housings for early Ford flatheads but I believe they were all 12V. The problem with 6V units is their size as compared with a 12V. Most auto manufacturers today would like to move to a 35 - 50 volt system because of the size of the alternator and the more efficient operation of a higher voltage system.

 

The reason for 12V was not that 6V would not carry the load but that for the same power device (expressed in watts) the current (amperage) is double. This meant that the wiring in a vehicle would be larger gauge than with 12V. The other problem is the size of windings required for a high torque starter in a vehicle. So the easy thing was to go to 12V, in most circuits, reduce the size of the wire and amperage of the fuses.

In a stock car with no extra accessories or air conditioning added, changing to 12V is not going to gain anything. Changing from Positive Ground to Negative Ground is simple. On a Ford, only the ammeter loop needs to be reversed, and the starter solenoid changed, and a couple of gauges reconnected. If there is a radio involved it will work as there were no 6V hybrid radios, all were totally vibrator powered. But there is no real difference between an alternator and a generator in operation except that the alternator puts out more current at idle and very low rpms than a generator which when running lights and fans at idle is an advantage.

Someone in the forum was a little confused about AC and DC. The alternator produces AC internally, but it is rectified by built in diodes and produces DC. So again, the only difference is to charge at low rpms.

I would not change from a 6V Generator to a 6V Alternator myself.

As far as cost, I would find a used generator and have the commutator turned and put in new brushes and bearings. If you can't do that, giving the rebuilder a workable armature with a good commutator or a working generator would reduce the cost.