one wire alternator or not

Sorry guys but i am getting old and forgetfull . I got a new delco alternator from a vendor at a car run a couple of years ago or more. my problem is it a one wire or not ? It has only one connection exposed. There are two connections i found under a hard rubber plug. I am going to use this to replce the generator on my y block. thanks,

 

that sounds like a 1 wire

 

It's set up to run 1 wire but with that plug out you can run it 3 wire.

I strongly suggest you run it 3 wire as 1 wire will have charging issues.

 

Seems to be a pretty broad statement. If it's build correctly, such that the coil is energized at an appropriate RPM (say... idle speed and up), then it should work fine. I've got a 1-wire that's been spinning for 15+ years without charging issues (I say this, now fully expecting the car not to start when I go out later ).

 

I wouldn't even call them issues. it's just that they are a little erratic...

 

Ha Ha!

You're vexing yourself!

However if 1 wire was the better way to go, don't you think those penny-pinchin' cheap bastards at GM would have done it years ago? Think of all the money they'd save on labor and materials.

The reason they don't: It just doesn't work properly, especially with electronic ignition.

 

But GM did do it......

 

Okay, enlighten me!

When?

On what models?

 

I like the 3 wire. The single one always leaves me guessing about what's going on. Gary

 

I retract my original statement as I thought they were original equipment. I was mistaken. It's really just a normal 7127 alternator with a special regulator produced by the aftermarket.

here is a good site on why 3 wire is better.

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

PS I don't really like 1 wires either....but they do work....sorta.

 

I've heard the same things about one wires not working and can only give what my own personal experience has been. I see NO difference in the way they charge whatsoever. We have had them on the last 4 cars and they always charge at the high 13 volt range, even at idle, and keep our batteries fully charged.

Even in the marine industry that I retired from one wires are becoming common. Arco and others are making one wired marine alternators more and more and ones with separate regulators less and less.

I even saw an article one time that said "Why one wires can't work" and I chuckled because that is all I have used for years and years, even on the Jeep I swapped a 5.0 Mustang into. I drove that as my daily driver for 5 years and had zero charging problems ever.

Don

 

I've only had one of them, it needed to be revved up quite a bit to start charging, then it was fine.

if the car has an idiot light, I'd rather use the idiot light and a 3 wire alternator and not worry about it. If it has a volt or ammeter, then a 1 wire can work ok. Might be harder to find a replacement in timbucktoo if you drive your car a lot.

 

I use the one wire. However, for it to charge, you need to rev the engine over 1200rpm to start charging.
In other words, say you pull into a parking spot and turn off the engine. Then, you want to restart the car (Like when your looking at the engine of the car you pulled up to.
If you just re-start it without hitting the gas pedal, it's not charging.

 

That could be the key, all of our engines idle at 1000 rpms, so maybe if you have an engine that idles lower than that it might not register until you rev it up a little.

Don

 

I never could see the point in having one. IF it works correctly, it's still doing the same job. So......

 

it will definitley be dead later

 

It's called lazyness!

Too lazy to wire it with 3 wires when they think 1 wire can do.

Also the "Billitheads" think that the extra wires clutters up and takes away from their expensive engine bling bullshit!

 

Thanks for helping an old guy out

 

All these guys have it right as far as why 1 wire alternators suck. My personal preference will always be 3 wire with an idiot light.

The only real point to having them was to appease the "wire-o-phobic" crowd. They crossed over into street rod popularity in the late eighties and early nineties just as "component panel" type do it yourself wiring kits became an available thing. From what I have been told, the original application for the one wire type alt was in stationary engines that ran at a constant speed from start up to shut off. Honestly, in my humble opinion, one of the most frustrating things when driving a car with a one wire that has an ammeter, volt meter, or idiot light wired in is watching it NOT charge while stuck in a never ending traffic jamb...

 

If your 1 wire alternator goes out while your on a cruise, good luck finding one locally. This happened to a friend of mine on this years Hot Rod Power Tour. They had to wait until the next day when one could be shipped in. Bummer. That ended the tour for them.

 

If it has the rubber plug it's probably a 1 wire.

 

Most of the rebuilt Delco10si and 12si alternators you get at your FLAPs will work in 1 wire mode. This is so they still charge if the bulb in the idiot light burns out. 3 wire mode is better, though.

 

Had to wade through some bullshit on that one! By the way, I vote 3.

 

I think the one wire got started because some guy thought it was cleaner to only run the one wire rather than have three wires. At least when they first showed up that was the big selling point.

As several said, with a one wire alternator you normally have to gun the engine after you start it to energize the alternator. That isn't a big deal unless you live in an apartment complex and go to work at 03:00 in the AM and have straight pipes. Half the guys I know who have rods give the engine a couple of quick raps after they start it anyhow just because they like to hear the pipes.

I'm still with the guys who say run a three wire setup though.

 

I run a three wire on pretty much everything I've built. I put one on my old John Deere Model B, and I have to open the throttle up on it to get the three wire to kick in. I wired it with the idiot light and remote sense lead, so not sure why I need to rev it to get it excited. Of course the old B idles at about 200 RPM, and the alternator doesn't spin too much faster.

 

I didn't claim they were better, only that, if properly built (ie, exciter engages at sufficiently low RPM), they will work.

As for some people's comments on availability, my local crap auto parts stores (AutoZone, O'Reilly, etc.) all have standard 12si case one-wire clockable units in stock. Perhaps where I live, they are more in demand (??).

 

I run one wire on both my cars with out any problems(knock on wood) but I think alot of electrical problems can be traced to bad ground.(you can not have enough grounds(the more the merrier)When i wire my cars I treat them as fiberglass bodies(a ground wire for every circuit) The frame and metal bodies are not good grounds use wire. Pete

 

You need one good ground for each thing in the car. You don't need more. And frames and body panels can be good or bad grounds, depending on how you do it.

Look up "ground loop" some time...there can be too many grounds....although it's not usually an issue unless you are dealing with an electronic system that is susceptible to electric noise (EMI).

 

Squirrel is right, ya gotta do it right. We have a standard old 72 amp Delco alternator that we "one-wired" on Flower's flathead roadster. It's been just fine for 18,000 miles and shows no sign of a problem.

Use what you want, my 2 cents worth says it works great either way.

 

I was in my 31 Model with original engine when my 1 wire quit working 300 miles from home. The town has a population of 3000 but has a parts store so I got another alternator and took my SE regulator out of the dead alternator and put it in the new one. That was 4 years ago and the new alternator is still working fine. I have 1 wires on two tractors, and 5 daily drivers and one Gordon Smith air compressor. 1 wires are great.