Upping the Output Amperage of the Ducellier

[NightFlyer]

Anyone ever successfully retrofit the Ducellier to provide a higher output amperage while running the stock/OEM pulley on it?

I'm looking at securing a spare alternator for #1798 to keep in the car should the original ever fail - that way, with my handy toolkit also in the car, I can swap it out wherever I may be upon the failure of the original.

Yes, I'm aware of the stock/OEM 90 amp Motorola replacement on later cars, as well as all the higher amperage alternatives offered by the various vendors, so please refrain from posting comments pertaining to such.

In this thread, I'm strictly interested in experience/advice/reference to shops from those who have successfully had the Ducey rebuilt to provide a higher output amperage with the stock/OEM pulley installed.

Thanks!

[Rich]

Interesting quest: a high-amp Ducy with the stock pulley.

Haven't heard of anybody who pulled it off on a D. In concept it can be done with a stator rewind. This assumes that the original pulley geometry will still transmit enough power to the shaft (because higher output will require higher input) even if the alternator RPM stay the same. And you are correct not to be shooting for an alternator RPM increase due to the risk of mechanically overstressing it at max engine RPM.

While a rewind with better/finer wire can up the output the risk is that the OE alternator air flow for cooling won't be sufficient. Upping the air circulation in and around the alternator isn't so easy.

Generally a good starter-alternator shop could give you advice about it - I do see your request for shops, which is the right direction to go.

There's a place that looks like they do this sort of thing - or will know how to direct you - in Lansing MI, not far from you. Let us know what they say.

LINK: http://www.precision-pwr.com/unique-classic-auto.html (http://www.precision-pwr.com/unique-classic-auto.html)

[Ron]

$.02

I was foreman in a very large rebuild shop in your neck of the woods days back when...anyway--
It is mainly the rotor that gives you more amperage. You can tell by how full they are. High amp rotors for the Ducy are all but NLA, Several places have brushes, holders, bearings, and rectifiers, but that is it. You will be very lucky to find a high amp rotor...and 80-90 is the max (the rotor is full). You can rewind your own but it is a real PITA w/o a proper set of jaws and press....

There was a high amp REMY unit out that had the Ducy case and other internals...been a while since I've seen one tho...

[Bitsyncmaster]

You would need to increase the field current and maybe wire gauge on both the field and stator. So it all depends if there is room for larger wire. Don't think you want more turns, that would make higher voltage. Larger wire would give you less voltage drop and more current. Of course the diodes would need to handle the extra current.

[Ron]

.. Except for rare occasions, the diodes and rectifier were all the same in the different factory units, and sometimes the stator if ultra high end option (usually the Chrysler POSs, until they went double field and electronic regulator). It was not worth having different sizes/rates. Early Motorollas had thicker stators (more plates and windings) and larger rotors overall.
If you worked with most any of them a while you could pick two up and know which was high amp by weight. Same with high torque starters (Now there, the field coils were larger too...easy to spot on a GM because they had a short copper spacer between the case and solenoid since they were so much longer to get enough windings in).

[NightFlyer]

OK, many great comments here - thanks everyone!

So, it sounds like it's possible, but probably impractical (which is why most just opt for one of the vendor replacements or cross references available).

I'll give that place in Lansing a call on Tuesday and see what they have to say and report back.

[David T]

OK, many great comments here - thanks everyone!

So, it sounds like it's possible, but probably impractical (which is why most just opt for one of the vendor replacements or cross references available).

I'll give that place in Lansing a call on Tuesday and see what they have to say and report back.

Even if you are able to make the Ducey generate more power it won't handle the heat. And the hotter it gets the lower the output so you reach a point of diminishing returns quickly. The alternator is already in a spot where it doesn't get a whole lot of ram air for cooling in the first place! On top of that the regulator and diodes won't handle the heat and the added power. If originality and reliability is what you are after, replace the Ducy with a Motorola and if you every decide to have the car judged in Concours you can put the Ducy back in. Very few people will ever notice your car is supposed to have the Ducy.
David Teitelbaum