One off Alternator Upgrade

[LifelikeStatue]

 The stock Hitachi 33amp was not doing it. At idle, the signals, blower or wipers would not work. Come to a stop and the wipers stop. Rev it up a bit and they start up. Clearly I had to upgrade. I work at a battery store next to a starters and alternator shop and the owner said he could help.

I brought the stock one in and found that the alternator from 92 Pontiac LeMans is almost a perfect fit. 90 amp, larger diameter but the mounts are near perfect, I had to use 3 washers on the front mount to line up the belt, and I was able to use the stock adjustment bracket. 

Here's where it's a bit fuzzy. He won't tell me exactly what he did, but he made it self-exciting. He said to unplug the external regulator and run one wire from the alt to the battery. I ran a piece of 2ga from the alt to the starter pole where the battery positive goes. No field wire needed. When I first start it shows battery voltage, 12.5, but once I rev it to 1800 the first time it jumps to 14.5 and works like a charm. I am running a voltage gauge to keep an eye on things but so far, perfect.

I don't have pics from the process but aside from pulling and cleaning the bracket and using all new hardware it was just old one out, new one in. I'm sure you've all changed an alternator before.

 

 

 

 

 

 

[Zeusimo]

I Assume This Is Internally Regulated?

[LifelikeStatue]

It is indeed.

[Ranman72]

nice I like it

[datzenmike]

This a well documented swap. Use the search function for internally regulated  alternator swap. There are two wires that should be cut and joined on the 510. BTW the stock 510 is 50 amp.

[DanielC]

An internally regulated alternator commonly uses the charge light (IGN in a 521) to initially supply current to the field coil in the alternator.  Once the alternator is charging, this is not needed.  The alternator feeds itself, until the engine is turned off. 

There is some residual magnetism in the iron pole pieces around the field coil.  Spin the alternator fast enough and this magnetism will make the alternator work.

[datzenmike]

This is why the voltage suddenly jumps. Maybe rewire it.

[DanielC]

Or live with it.  I have an old gasoline tractor with a one wire GM alternator.  When it is cold, it needs the right amount of choke to start, and immediately less, but still the right amount of choke to keep running.  Before the alternator self energizes, there is no load on the engine from the alternator trying to recharge the battery.  When the tractor is running smoother, I blip the throttle, and the alternator kicks in.

[Z-train]

Not charging at idle is a simple fix. A smaller pulley. Any good rebuilder will have them. Amp capacity is another issue altogether

[LifelikeStatue]

It does charge at idle just not at first startup. Once you rev it to 1800 once, it charges just fine.

[Z-train]

It does charge at idle just not at first startup. Once you rev it to 1800 once, it charges just fine.

The small(er) pulley will cure that as the alternator will be spinning faster at idle.

[Boaty]

Old bread.

But that smaller pulley will also have negative side effects.

 

1.) Over-revving the alternator.

2.) Loss of belt traction (loss of contact area)

3.) More squealing, see above and add less leverage from the belt drive assembly.

4.) Premature wear.

Stick with the stock pulley.
1 wire conversions are fine, if you can deal with the throttle blip.
I personally choose a charge light over a self-exciting coil. I like to see when things are bad visually without having my eyes glued to a gauge.

Lucky for me, my gauge has programmable warning lights, and they are bright enough to get your attention mid-day.

 

 

Food for thought.
 

[Z-train]

Old bread.

But that smaller pulley will also have negative side effects.

 

1.) Over-revving the alternator.

2.) Loss of belt traction (loss of contact area)

3.) More squealing, see above and add less leverage from the belt drive assembly.

4.) Premature wear.

1)inconsequential-alternators are good to 18,000 to 20,000 rpms (type depending)

2)in-correct-contact area is not diminished

3)In-correct-Squealing is a tension/adjustment issue

4)in-correct.5 years on every vehicle(sans my Cummins) I own plus my Bobcat with no issues.