Alternator Replacement Upgrade?

[kazam]

Greetings,

 

I may have to replace the alternator for an I-4, 150 c.i., without Air Conditioning, '87 Comanche.

The local parts store had an O.E.M. replacement at about 61 Amps, and another at 74 Amps.

 

I will likely go with the 74 Amp replacement.

 

I am wondering about other higher amperage options that may be a direct bolt in.

 

Thanks.

 

 

[Vakarian]

I installed a 134 amp from a Grand Cherokee on my buddy's and mine MJ. However, due to the larger diameter of the alternator a bit of grinding on the brackets to get it to fit was required.

[MJXJjeepguy]

Or u can relocation ur alt on top of AC bracket but i not sure about I-4? Never experience with those engine. What I have is 4.0 and i remove AC bec it no longer work anymore and will need alot parts to get it work so I relocation alt with higher amp to top of AC bracket and get shorter belt.

[Jeep Driver]

For 105 amp you can use one for a '86 Caprice with the V6. It's not a direct bolt in, you have to re-clock and drill a new hole in the bracket because it's about 3/4" taller.

 

For a direct bolt in- 

 

[yxmj]

134 Amp alternators off of a 3.7 liberty should be cheap and plentiful at JY's in your area.........Just a little grinding to fit

 

You can even spend a little time with a wire wheel and polish it up to look like chrome (which will add HP and Mileage to your MJ)

[DirtyComanche]

2 hours ago, yxmj said:

134 Amp alternators off of a 3.7 liberty should be cheap and plentiful at JY's in your area.........Just a little grinding to fit

 

You can even spend a little time with a wire wheel and polish it up to look like chrome (which will add HP and Mileage to your MJ)

 

Are those internally or externally regulated?

 

I'm guessing external.

[Jeep Driver]

5 minutes ago, DirtyComanche said:

 

Are those internally or externally regulated?

 

I'm guessing external.

Yeah, I suspect so.......regulated by the ECM. 

 

 

Some guys make a lot of work out of saving a penny or two.

[kazam]

Greetings,

 

Thanks All for the helpful replies.

 

For my configuration, I am interested in that 134A Grand Cherokee possibility that "Vakarian" posted.

 

How would that work?; have you got a picture of the modification required?.

I have not got a probelm with upgrades and work for such; I would like to find out a few more specifics before ordering parts.

Have you got a part number for the Grand Cherokee alternator, or a Year and Engine (so many various Grand Cherokees exist).

 

Also, would a different-than-stock engine/serpentine belt be required?.

 

Again: 1987 150 c.i. I-4, Without A/C.

 

Thanks Again All for the helpful replies.

[Jeep Driver]

29 minutes ago, kazam said:

For my configuration,

 

29 minutes ago, kazam said:

before ordering parts.

 

 

Do yourself a favor, really. 

 

https://www.jegs.com/i/Powermaster/713/58137/10002/-1?&mrkgcl=1239&mrkgadid=3328062169&adpos=1o1&creative=329886787812&device=c&matchtype=&network=g&jegspromo=thirdparty&gclid=Cj0KCQjwjMfoBRDDARIsAMUjNZrADJmkBG3aoQtkbzk8xk7OToXUzKIRHPRahbASmioI67YcZIulLlMaAg3XEALw_wcB&gclsrc=aw.ds

[Manche757]

On 6/25/2019 at 9:06 PM, Jeep Driver said:

 

 

 

Do yourself a favor, really. 

 

https://www.jegs.com/i/Powermaster/713/58137/10002/-1?&mrkgcl=1239&mrkgadid=3328062169&adpos=1o1&creative=329886787812&device=c&matchtype=&network=g&jegspromo=thirdparty&gclid=Cj0KCQjwjMfoBRDDARIsAMUjNZrADJmkBG3aoQtkbzk8xk7OToXUzKIRHPRahbASmioI67YcZIulLlMaAg3XEALw_wcB&gclsrc=aw.ds

Does that fit directly without any mods?   Had a/c put in and probably need a bump up

[Dzimm]

Idk what the mounting bracket is like on the 2.5L but I went in to AutoZone for an alternator for my 98XJ (4.0L) and their computer showed a 134 amp one for the XJ.  I'm guessing it is the same one as the grand Cherokee and I had to grind the bracket slightly just like Vakarian mentioned otherwise it was bolt on.  

[Jeep Driver]

4 hours ago, Manche757 said:

Does that fit directly without any mods?   Had a/c put in and probably need a bump up

Yes, direct fit. 

[desertmike]

Took mine to the local starter/battery/alternator shop and had it rebuilt to 140 amps for $140. 

 

edit. No fitment problems that way.

Edited July 2, 2019 by desertmike

[kazam]

I had a timeline to work with.

The parts store has a CS 130 (105 amps)  in a day or so that I intend to purchase for a backup for the Comanche or otherwise for my Jeep Pickup.

Wilson Line (DELCO) PN:  90-01-4612  (at O'Reilly's).

I had to get to work on time; I opened up the Comanche (stock from when I got it) alternator ((who knows) 64A or 71A).

I found the rotor surfaces at the bushing contacts glazed.

 

I cleaned those (with some 180 Wet Dry as available, Carefully) and put the alternator together with some safely wire.

Two of three case fasteners broke in the alternator casing during disassembly.

I drilled and removed and extracted with penetrating oil and heat before and otherwise.

The fasteners' pieces were in there; I even broke an extractor (#2).

I am not attempting to 'skimp' on quality or money.

The alternator in the MJ works Great now.

 

I had thought it might be the voltage regulator (internal) or the brushes.

I hoped it was not a field winding; it was not.

The brushes yet looked Good to Run.

 

The "stock" alternator just requied some care.

And I am sure to mention that the 90-01-4612 may require switching out of pulleys.

 

For my work schedule and resources this is the option I found.

 

Thanks Very Much.

 

 

 

[MeanLemons]

Don’t forget to upgrade your battery cables if you go with bigger alternator.

[Eagle]

On 7/1/2019 at 9:27 PM, desertmike said:

Took mine to the local starter/battery/alternator shop and had it rebuilt to 140 amps for $140. 

 

edit. No fitment problems that way.

 

Doesn't work for the 61-amp models.

 

The early XJs and MJs use Delco internally-regulated alternators. Those came in two frame sizes. I don't remember where the cutoff was, but the 61 and 74 amp alternators are definitely the smaller frame.

 

I needed an alternator for my '87 MJ 4.0L. I took it to the local rebuilder guru, who initially assured me that he could upgrade it to 125 amps or something like that. When I went to pick it up he announced that he wasn't able to upgrade it because my old one was the small frame, and to get the upgrade would require a large frame.

 

If you want to keep things simple, get the 74-amp from the parts store. You can buy a larger one by looking up alternators for 4.0L XJs with a/c, but then you may run into having to modify brackets.