The Stovebolt Site Forums The Shop Area The Electrical Bay Alternator modification - sort of. Lining up a one wire alternator.

I bought a new 1 wire alternator so I can get rid of the regulator as well as have more amps.

I knew before I ordered it that the pulley would not line up if I used my factory alternator mounting bracket from my L6 250ci.

I want to know if I can remove the pulley and fan assembly from my old alternator and swap it onto the new one. Also, the new alternator has a smaller diameter pulley which means it spins faster. So does that mean it will make fewer amps if I successfully swap on the older pulley which has a larger diameter?

Of course, I could fabricate a new bracket that will properly align the pulley with the HB, but to me, swapping pulleys seems easier (maybe).

What advice do you have?

Old and new alternators - new has a smaller pulley

Old alternator lines up beautifully!

New alternator pulley is not going to line up.

Both have a 15/16" nut but old nut needs an offset wrench to reach the nut.

Swap the pulleys and you'll be fine. The offset pulley has to be on to align the belt.

The small diameter pulley is going to be needed to make the alternator start charging on startup. It spins the rotor faster and gets the charging started sooner. With the bigger pulley you will need to goose the throttle after starting to get the amps flowing. Search "2-groove alternator pulley" on Ebay. There are at least 20 of them listed today. Install the 2 groove small diameter pulley and use the front groove, and things will line up right. I use an impact wrench and a 15/16" socket to install/remove those pulleys.
Jerry

Thanks for the tip. Will I need to change V-belts?


My son suggested doing that but the shaft will spin with the nut, won't it? That seems like it wouldn't work. I spent 2 hours today searching local hardware stores for a 15/16" offset box wrench. Couldn't find one.

If you use the impact gun the shaft should not spin after the nut is loose,also make shire the belts do not bottom out in the groves of the pulley,if they do it means that the belt is worn out,look at the groves in the pulley and make sure that the sides have not worn out also. Belts have two widths, one is an "a" width and one is a " b" width. Pat

If you wire it as a three wore alternator you don't have to worry about ordering a different pulley. It will start charging on start up. Most of the time with the one wire though at start up the engine is usually revved up enough to start it charging before idling back down.

It's really not enough of an issue to hunt a different pulley when you have one that will be fine. Putting it in reverse or lwo to take off will give enough rev to make it turn on.

But Hotrod is right, using a smaller double v-belt pulley will turn the shaft faster making it turn on usually without revving the engine.

The rotor has enough inertia for the impact to spin the nut on and off without a problem. Conservatively, I'll bet I've done several hundred that way, maybe a thousand or more.
Jerry

Like Jerry says, use an impact it will work just fine. I've done it many many times myself, without a problem.

As usual, there's great advice on this forum. Thanks.
I'm a novice, as we all were at one time. LOL!
Having just completed the pulley swap, I thought you might like to see the photos. I thought the fan was connected to the pulley but I see it's just pinched in place. Can anyone tell me why the blades are not all the same?

Another option for me might be to make a 2 + 3/8" diameter shim and use the small pulley. That's only if this way doesn't perform satisfactorily.

Nut came right off with the impact. Good advice!

Pulley and fan are off.

Old pulley cleaned up pretty good.

All back together.

Seems like a 3/8" thick X 2 + ...cate the inner shoulder would also work.

Jay

Unless you can counterbore the smaller pulley from the front, you'll run out of thread area on the shaft after shimming it out. No way to reinstall the nut and lockwasher.
Jerry

Yes sir. You are very correct. I missed that detail. I think what I've got will probably do just fine. If not, then I might just fabricate a new bracket.

I bet it will be fine. A lot of times after a few starts the one wire will start working right away. If not just goose the gas a little or if standard shift put it gear and as you rev the engine just a tad to take off it will go to work.

You can try inverting the alternator and see how it lines up. Mount the alternator's factory top bolt holes on the outside of your existing mount. You'd still need an offset mount, but it wasn't difficult to make one. Photos of what I'm trying to describe. You'd also want to flip the back plate so the 1-wire connection is away from the engine.

Brad

Pulley swap is done. Things line up very nicely too.
Anyone see a problem with this setup? Photos I have on file show the alternator in the same position.

Old pulley on new one wire alternator lines up well.

Back side of one wire alternator after installation.

Just keep the wires away from the manifold. Now you know why ClaudeTheTruck, rotated the back cover. I pulled the wires over to the inner fender straight from the back of the Alternator. A clamp and all was good.

Yes, my file photos show the original wires go from the alternator over to the DS inner fender.

Alternator on my 230 engine. Probably not the original alternator though.

Another file photo.

While not identical, the wiring locations are very similar.

Brad,
These 2 videos on YouTube helped me understand what I will see inside an alternator. I was reluctant to take mine apart for fear of the unknown parts inside. Now I see that removing and rotating the back cover is nothing to fear. Thanks for the tip!

Alternator Video 1

Alternator Video 2

All you need is a straightened-out paperclip to hold the brushes back while you clock the rear housing to the position you want. Just be sure to keep the stator and the rear housing together.
Jerry

And where exactly would I put the paper clip?
Update! Never mind. I just opened up the case and the brushes popped loose.

I got it all back together just fine. On another note, after watching those videos I see where he says you can excite a self exciting alternator by briefly supplying 12 volts to the #1 terminal. That could be done with a simple push button located on the dash or hidden somewhere. Of course it might not be needed at all. Just another way to get the alternator excited without revving the engine.