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Durango Alternator Swap Compatability

Might I also recommend that you swap the pulley from the XJ alternator to the ZJ alternator... By using the ZJ pulley the alternator will turn slower which will require the engine speed to be increased to get the same charging rates.
When I did my alternator swap many years ago...

According to other threads I read, this step is not necessary. I'm reading from other folks that you just leave one rib open on the ZJ pulley and it works with no harm or ill effects, however you state that it will pull slower. Not having a XJ and ZJ pully here to compare, I take it that the ZJ pulley is larger? Is that then to assume that the XJ belt will not fit either?

Lots of good threads on the alternator swap...however this pulley issue seems to be one piece of conflicting information where there is no definate as to what needs to happen.

I'd welcome further explaination from either you, CharlesS or from you, Markos as to why you decided to take the step you did with the pulley.
 
I suppose that one could compare the two alternator pulleys and the crank pulleys to get an idea of how much slower the alternator will turn in the XJ. Keep in mind there is a mechanical advantage to a slower turn so, I am of the opinion that if it fits the needs at idle, run the larger pulley and save a couple of HP...
 
560041394AA is the part number for a factory alternator that is supposed to put out 150-160 amps and bolt in to the 91-98 Cherokee. I have not found a parts house that has a crossover for the part number. You can check the junk yards or get one from Quadratec or Morris:

http://www.quadratec.com/products/52449_5604.htm
http://www.jeep4x4center.com/alternator-56041394aa.html
48285-lg.jpg


Figured it was good to add in case someone searches for this in the future.
 
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Measure the diameter of the two pulleys determine the % difference and compare RPM load ratings.
My idea is that it creates an overdrve affect.

It would be more like an "underdrive" effect - and "ovedrive" would increase spindle speed, an "underdrive" would reduce it.

Akin to the "underdrive" pullys you get from various vendors for more common engines to free up power to go to the wheels...
 
560041394AA is the part number for a factory alternator that is supposed to put out 150-160 amps and bolt in to the 91-98 Cherokee. I have not found a parts house that has a crossover for the part number. You can check the junk yards or get one from Quadratec or Morris:

http://www.quadratec.com/products/52449_5604.htm
http://www.jeep4x4center.com/alternator-56041394aa.html
48285-lg.jpg


Figured it was good to add in case someone searches for this in the future.

I just tried to look it up by OEM# in my Superior catalogue to get a Cham/Lestr number, to no avail. Got an original application? If it's before 2006, I can look it up in my book - after would take some doing...

But, the Cham/Lestr number is nearly universal, and can be used anywhere (even without the OEM# crossover.)
 
I just tried to look it up by OEM# in my Superior catalogue to get a Cham/Lestr number, to no avail. Got an original application? If it's before 2006, I can look it up in my book - after would take some doing...

But, the Cham/Lestr number is nearly universal, and can be used anywhere (even without the OEM# crossover.)

1998 Jeep Grand Cherokee 5.9L. All of the parts houses only list a 136 amp for this application.
 
Old thread I know. I've had a NOS Denso 121000-4171 136A alternator from a V8 ZJ on my 91 MJ for years and need to pull it to check the brushes soon. Under full load at idle, the VM indicates a negative charge until the RPM increases to about 1200 RPM. It's done this since install, and I do have the Jon Kelly mains cable upgrade installed, and have discussed it with him via emails when I installed it. Voltage across the battery is fine (14.3V or so) when checking with a multimeter. The alternator has the stock Jeep ZJ 7-rib pulley on it, and while I have it out, I'd like to change the pulley for a smaller slightly diameter 6-rib pulley to speed up the alt RPMs slightly. Can anyone recommend a good aftermarket billet pulley for this application? Or how about using an original XJ pulley from a 90A Denso alternator? Are they slightly smaller in diameter? Thanks all.
 
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