ALTERNATOR ???

[MIDNIGHT RIDER]

I picked up a newly rebuilt alternator from the estate of a guy that made his living rebuilding starters and alternators.

The alternator on my 1985 F-350 is externally regulated, with only ONE wire contained in the plastic plug that has TWO terminals.

The wire that is there is on the terminal that is marked FLD (field).

The un-used terminal is marked STA (stator--I assume).


The new-rebuilt alternator that I got from the estate has a tag that says 70-amp FORD, and is identicle in appearance to the one on my truck, with the only difference being the not-so-thick mounting hole is about half the thickness of the one on my current alternator.



I just had the guy at Advance put this alternator on their test-machine.

He asked me what make/model, so that he could set up the machine accordingly; then, he asked me if the two terminals had anything plugged on them and I said YES.

He ran the test and said the voltage was in good shape and all was fine, except the STATOR light came on, indicating a problem with the stator.



Is it possible that he connected something to the un-used STA terminal and got a false reading ??


What does the stator do and what does the stator light mean ??

Why isn't the STA terminal used on my truck ??




There is nothing wrong with my current alternator; I just picked this one up for dirt-cheap, in the event that I should need a spare.

Thanks.

 

[h2odrx]

I think 70amp is not enough? needs to be 100 or 130?

 

[Neal J. Moran]

The stator terminal on that alternator, white w/black wire, puts out the alternator or battery light on the dash. If your vehicle does not have this wire, then the dash only has a gauge, no light.

The thickness of the adjustment ear was dependent on the part # of the alternator. I believe we saw the thicker one on the V6 cars. I can't remember the Lester #. The housings could be interchanged.

If you have an alternator failure, the best thing to do is convert to a 3G, or third generation, alternator. They are Bosch clones and last forever. If you buy a used one, then you should look at the slip rings for wear, first. If the slip rings are bad, replace the rotor and you won't have a worry again for years. You can go to 130 amps with this unit.

 

[MIDNIGHT RIDER]

I think 70amp is not enough? needs to be 100 or 130?

I thought factory original for these trucks was something like 65 to 70 amp.


What amperage is the factory standard equipment alternator ??

I just picked this one up as a direct bolt-on spare to carry for emergencies; it isn't my intentions to run it full time.

I once got caught in the dark, in a hundred-degree heat, with a load of horses, and a locked-up alternator; a spare would have been most convenient.

Thanks.

 

[JPR]

My factory alternator was 70 amp also.

Since you have a 5.9L, this alternator would have looked more at home on your truck.

 

[MIDNIGHT RIDER]

Since you have a 5.9L, this alternator would have looked more at home on your truck.

That would be nice.

One reason I kept the Motorcraft alternator is that I am often a long ways from home, with valuable livestock, and like the security of being able to find/fix whatever minor situation develops with whatever is readily available at whichever parts-house might be open.


If I do ever upgrade to one of the higher-performance alternators, I will buy TWO.

 

[Diesel JD]

The 70 amp was stock, most replacements are 100A. Since you have a Cummins and thus, no glow plugs, you have eliminated one of the things that drains our batteries the most. Unless you have a big sound system or something I doubt 70A will be a problem, especially since you will be using it just for emergencies.

 

[MIDNIGHT RIDER]

The stator terminal on that alternator, white w/black wire, puts out the alternator or battery light on the dash. If your vehicle does not have this wire, then the dash only has a gauge, no light.

Besides controlling a battery light, does the stator perform any other function ??

Thanks.

 

[-=DeanstuD=-]

Here is another vote for 3g upgrade. best $20 I spent yet...

 

[JPR]

The more I look, the more interested I become.

What is the Cummins part-number for that unit ??
What were it's original applications ??
Who builds it for Cummins ??
Thanks.

The 24SI is a Delco Remy heavy duty alternator. This one was a new take off from a Cummins powered snowcat. The Cummins number on the alternator is 4936878

I thought I had researched it enough before buying it, but it turns out this a disposable alternator unlike many heavy duty alternators. It is a newer model alternator, so it is not very common. If I did it again, I would install the 3G.

Pro's of the 24SI
It has a much larger shaft and bearings than either the factory alternator or the 3G.
160 amp (depends on model)
Dual internal fans
Single hot cable hookup

Con's of the 24SI
Is not a bolt in replacement on the idi, custom bushings & machining required.
Fuel filter has to be moved.
The rectifier is soldered to the field winding
Unlikely to find another 24SI if on the road, unless there are a lot of newer snowcats where you live.

I would only recommend it for a non-idi install and then only if you get it really cheap.

 

[MIDNIGHT RIDER]

Pro's of the 24SI
Single hot cable hookup

So I guess that means internally regulated, right ??

I have a nightmarish fear of internally regulated alternators.


Thanks for the advice.

That is still one serious-looking piece of equipment.

 

[JPR]

Yes, the regulator is on the back. In the picture it is on the top right, it turned silver in the picture due to the flash.