alternator..what is it? etc

[claybill]

i hear talk of alternators installed on 6v plymouths. i know it is a generator substitute of sorts but.....? what and why? is it an easy swap? what is the advantage? changes?

bill

[norrism1]

Claybill, An alternator gives continuios charging, while a genny only charges at a preset RPM. Alternators have 2 charge levels usually, low charge for idle and the full charge kicks at a preset rpm. (Determined by factory preset depending on manufacturer). If memory servers me correctly about 800 to 1100 RPM for the high side to kick in to charge. Advantage is easy replacement from an Auto parts store as it is still common to buy. You would need to get a mounting kit to go from the genny to the alt and they are about $50.00 depending where you buy it. You eliminate the voltage regulator as the single wire GM that I used on my 51 B3B had the regulator internal to the Alt.

[55 Fargo]

They make 6 volt + ground GM single wire alts in my area for around $100.00.

The advantages are noted above, you could also fab your own mounting bracket if you are so inclined. The GM single wire alts are cheap and plentiful, but an Auto Electric Shop has to convert them to 6 volt + ground. Thats is why there a little more expensive than the 12 volt easy to find models....................Fred

[Plymouthy Adams]

well..you explainded the one wire pretty well n the fact that it has to be revved to a certian speed to tickle and charge..else you can prewire it to sense voltage at key on and it will charge at any varied rate from low to high depending on engine speed and current demand..being internal..it is a simple one wire..being a one wire it is a pain to split and detect if alternator is the problem or the regulator...you can use a good dual field chrylser unit, simple 2 second test to diagnois alt/reg, brushes are changed while unit is still mounted on the engine...I personally cannot see any advantage to the one wire..and my best excuse for last...I have never had to change one of these in my life..I have only had to put on two regulators due to flux charge (lights flickering) bushes are routine items to replace but the interval is great

[Young Ed]

Tim I will second that. I've replaced lots of GM alternators on my friends and families cars. My moms olds tossed the first one before 50K miles. My dakota still has the original at 171K. You'll never see a GM do that.

[norrism1]

Guys, I was just trying to keep it simple for him. He can use the large wire already in the loom to setup the GM Alt. I agree the mopar is better but I went with the 1 wire GM due to low mileage I expected to put on the truck and wasn't worried about failure for a LONG time. And I did forget to mention mine was converted to 12 volt Neg ground. Sorry for the confusion. I'll go sit in the corner for 1/2 hour now!

[Plymouthy Adams]

for simplicity the GM get lots of attention..but when things go wrong they be a bit of a pain..and if you were to run the exciter voltage from the ignition..even the GM one wire would be greatly improved but then it no longer is a one wire though...many many choices out there when it comes to modifying and one usually goes with what he is most familar with...not wrong answers..just varied answers.

[claybill]

guys....it all sounds complicated. what is the advantage? is it necessary?

if so where do i get the gm unit...or the dakota..salvage yard??

anythg else on the wiring that needs to go with it?

claybill

[greg g]

As noted the alternators charge at lower RPM. they were originally designed for military and police vehicles that spend a lot of time at idle usually with a heavy load of electrical stuff running. The one wire is easy to connect and for our uses probably the shadetree way to go. Basically after you get your bracket set up (Don C's photobucket shows an easy home fab bracket) all you do to hook it up is run the wire to the wire formerly connected to the battery terminal of your voltage regulator. While disconnecting and abandoning the others as the regulator is no longer needed. If you want a 6V positive set up any Ford Model A parts catalog place will have them. If you want to convert to the GM 1 wire, you can get them remaned at any autoparts store in the world for 70 bucks or so, and at the wrecking yard for about 25 bucks. You will probably need to change the pully. Switching to 12 V neg is a procdure that has been discussed many times on this forum and other sources. But if you are not having any problems with your charging and electrical system, just keep your system maintained and you shouldn't have any problems.

[martybose]

One clarification about the 1 wire GM's; When you first start your engine, the alternator doesn't charge until the first time you exceed the trigger RPM (about 2000 RPM in my case). Once it has triggered the first time it will charge at any RPM, idle included.

Marty

[48mirage]

Try this thread for learning about how what alternators are and how they work.

http://www.alternatorparts.com/6_volt_alternators_&_kits.htm

My experience, I bought a junk one from the salvage yard, took it apart cleaned it up and converted it to 12 volt positive ground single wire for my purposes. $10 at the salvage yard, about $50 for the conversion kit, and pulley probably another $20 for the universal mounting bracket. I bought the parts to modify the alternator, bracket and pulley from ebay stores. This is the first time I had ever been into an alternator. Turned out to be fairly simple and straightforward. I'll never hesitate to open one again.

[Jim Shepard]

i hear talk of alternators installed on 6v plymouths. i know it is a generator substitute of sorts but.....? what and why? is it an easy swap? what is the advantage? changes?

bill

You might go to this web site and check out the rationale for using a 6V alternator. I put one on my 1950 Dodge truck and I'm very happy with it. My truck is a every day driver, so I was looking for good starts and better charging. I also didn't want to mess with resisters and such that a 12V system would have required. While we don't usually get real cold winters in this part of California, I've never had a starting issue. I rarely have to use the choke.

http://www.fifthaveinternetgarage.com/

[Don Coatney]

One clarification about the 1 wire GM's; When you first start your engine, the alternator doesn't charge until the first time you exceed the trigger RPM (about 2000 RPM in my case). Once it has triggered the first time it will charge at any RPM, idle included.

Marty

That is exactly how my single wire mid 80's GM alternator works. Only difference is my excitment speed is around 1200 RPM's. My alternator does not have two charging rates as someone mentioned earlier in this thread. I have never heard of an alternator having two charging rates. It will put out full current at idle once it is excited. The internal regulator in my alternator only allowes it to put out the level of current required to maintain 14.7 volts in the system.

I bought my alternator as a used rebuilt unit at a bubble pack auto parts store for about twenty bucks six years ago.

[Niel Hoback]

I got my 6v + grnd at a swap meet a few years ago. It does need a shot of rpm's to get it working, but after that, its good until I shut it off. The charge rate is very smooth in that it puts out about 25 amps at start-up and drops smoothly to about 5 in a few minutes.

The best part is that it will stay on the positve side even at idle with the headlights and radio on. The DC generator couldn't do that.

Never heard of two levels of charge rate. Regulators adjust constantly, eliminating the need for "levels".

[Reg Evans]

What does this mean???? At night with the lights on in my 64 Valiant w/new alternator I can see the dash and headlights pulsing brighter/dimmer/brighter/dimmer. Maybe 2 pulses per second.

I was also surprised ,when I was changing the timing setting with the engine running, to get a spark from the socket extension which was touching the dist. lock down nut and the inner fender panel. Then another spark when I was tightening the lock down nut and the end of the socket wrench touched the rear of the alternator (not a connector)

[martybose]

OEM Mopar alternators are notorious for not putting out much amperage at idle; it is typical to have a slight discharge if the lights are on.

Marty

[Plymouthy Adams]

OEM mopars charge at the rate of demand with fully charged battery still yielding 8 amps for ingnition etc so as to to source the battery if you have less output..you may have a faulty diode...

[david lazarus]

When I rewired the '38 I fitted a Ford alternator and went 12V neg earth at the same time. The Ford Alternator was an easy fit, and the pulley was already narrow. To a simple guy like me the one (heavy duty) wire back to the battery for recharging was a no brainer. I did fit an "alternator charging light" as well as this was part of the system and then because I often doubt my own skills (sometimes with good reason) I also fitted an aftermarket voltmeter to monitor the battery.

It all bolted up and went first time, and worked well until the wire fell off the alternator terminal because I failed to do it up tight....hence "doubt about my skills" is reinforced:D !!!

[55 Fargo]

That is exactly how my single wire mid 80's GM alternator works. Only difference is my excitment speed is around 1200 RPM's. My alternator does not have two charging rates as someone mentioned earlier in this thread. I have never heard of an alternator having two charging rates. It will put out full current at idle once it is excited. The internal regulator in my alternator only allowes it to put out the level of current required to maintain 14.7 volts in the system.

I bought my alternator as a used rebuilt unit at a bubble pack auto parts store for about twenty bucks six years ago.

Hi Don, can you post some photos of the alternator bracket you fabbed to fit on your engine............Thanx Fred

[norrism1]

Guys, I have a nice rash from all the butt kicking about 2 charge rates. I admit I was probably wrong, I remember when younger (much younger) I was told about 2 levels of charge from an Alt. I must have been either mis-informed or memory is slipping! My apologies for the incorrect information.

[Don Coatney]

Hi Don, can you post some photos of the alternator bracket you fabbed to fit on your engine............Thanx Fred

Fred;

Go to my Photobucket linked below. Then open the alternator album and you can see all my alternator pictures.

[Guest jjmorrse]

tex smith wrote a book on auto electronics that has a lot of diagrams for charging systems. I have an electronic regulator and a mopar "squareback" alternator that I am happy with. My two cents, it is easy to find a high amp alternator, but if you do not have a lot of accessories, if the system gets discharged, a high amp may be more likely to overload your wiring and stress the system.