Alternator swap question

[Crankyolman]

As some of you know I have upgraded my '72 J4500 to fuel injection. As a result my truck is now pushing the limits of it's little 30 amp Motorola alternator and I need to upgrade it to something better.



So that brings up the big question, which alternator do I replace it with?


I've been thinking about this one which is technically for a 1980 Cadillac

https://www.autozone.com/batteries-starting-and-charging/alternator/duralast-alternator/333393_969991_0

But would this one be a better choice because it's for a 1980 J10?

https://www.autozone.com/batteries-starting-and-charging/alternator/duralast-alternator/333377_802605_0

Then there is this one from Amazon which has good reviews but I'm concerned it might be too large to fit.

https://www.amazon.com/ACDelco-335-1094-Professional-Alternator/dp/B007QBRAMM/ref=sr_1_67?keywords=ac+delco+alternator&qid=1558836037&s=gateway&sr=8-67

Would one be easier than the other to put in my truck? I'm not afraid to do things that could void a warranty like cut away bits of the mount to make it fit. I know what I should do is head down to Pick-n-pull and get one there but that takes more time than I have to spare so the auto parts store is the best option right now.



Thank you for any input on this.

[Ristow]

A Delco 10si or 12 si will mount right up and wire in in a few minutes.


run the field wire to your (should be) unused I terminal on the starter solenoid. hook the S wire to one of the switched wires up on the intake,like the idle solenoid lead.




also,get one locally,so when it doesnt work out of the box you can exchange it easily.

[Crankyolman]

My understanding it that because my truck is a '72 the mounting leg will have to be cut down from 2" to 1 1/16" to fit the bracket, which is no big deal to me but voids the warranty if it's noticed if I have to bring it back. Did the later J10s that used a delco alternator have the wide leg or was it narrower?



Another concern I have is I saw a post from someone with a'73 or '74 who had a problem with the alternator hitting the oil filter which is something I really don't want to deal with. Is the 12SI a lot larger diameter than the 10SI?

[Ristow]

i dont recall needing to modify anything to put the delco in mine. maybe i did get the later mounts.



get a slightly longer belt if needed to swing it away from the filter.

[fsj454]

ac delco

Looks like you will have to rotate back housing on the delco to fit .I had to rotate my powermaster 12s . Remove bolts and rotate do not pull apart

[PlasticBoob]

When I was converting over to fuel injection, it was recommended time and time again that you want to go with something that puts out "clean" power to the ECU; this is why I went with a CS-130 over the older SI alternators.

The SIs can put out "dirty" electricity that can possibly cause all kinds of random gremlins in the system. Even though it's from the 1980s, the CS series was designed with fuel injection and modern electrical needs in mind.

I also remember reading somewhere that the SI alternators may not pump out enough amps at idle to support the EFI system and fuel pump.

Food for thought.

[lkmarsh]

x2 on considering the CS-130. I had no problems replacing the 10si.
At the time the CS-144 was all the rage, but it is larger so fitment isn't so easy.
Also think twice about dealing with AZ. Odds are good your new rebuilt alt won't work.
Too many stories about bad parts. New starter solenoid killed my battery.
Better to take a core to your local alt rebuilder. Never yet had a problem.

[tgreese]

There is a bracket available that will adapt the Motorola mount to Delco: https://store.alternatorparts.com/a2...n-bracket.aspx

I recall the '78 and later V8 Jeeps are equipped with a 10SI Delco, so you could possibly use the brackets from a later engine.

[acct21]

The brand new CS-144 I put in my '90 was a direct fit. It does have a larger case, which required going up 1 inch on belt length, but it fit without modifying anything.

I used one out of a '94 Camaro, which was apparently a fixed (post) mount that used a serpentine tensioner. The mount ears on this application were identical to the 12SI I pulled out.

Had to use the 4 pin CS-to-2 pin SI adapter harness, but it all plugged in and has been a massive improvement over the 12si.

[babywag]

72 vs 90 alternator and brackets are different animals.
unlikely that a cs144 would drop in without modification(s)
also motorola vs. delco wiring is much different as well.

[Crankyolman]

Thank you for all the input everyone.


I understand how to wire the 10 or 12SI as well as what needs modified and how to make the wiring work. This website explains it pretty well

http://www.planethoustonamx.com/main/amc_alternator_interchange.htm

In case you don't know this is what my alternator bracket looks like

As you can see it is one piece it mounts low on the right side and the upper mounting area is only 1 1/16" wide. I don't mind modifying an alternator to fit that.




I don't understand exactly what installing a CS-130 would entail, do they use the same 3 wire setup? None of them seem to say what wiring setup they have. Will I still be able to hook up my amp light? I like my amp light and I like it to work. I don't like having a bunch of aftermarket gauges cluttering up my cab. I don't really mind cutting and modifying the alternator but I really need to know that this will work before I do it. I know everybody thinks buying local is the way to go but in the past I have run into major garbage that way and then had to get irate in front of other customers to get them to take it back. Amazon will deliver an alternator to my door within 24hrs and and will pay return shipping if it needs to go back. On top of that in all likelihood they will refund my money as soon as it is shipped back regardless of the condition of the returned item, even if I ship back a bag of horse dung in it's place (this actually happened but not by me). So I like to go with Amazon because I know the secrets about returning stuff. That said I'd rather not have to return anything and the brand new 10 and 12SIs have very good ratings and are half the price of the one CS-130 I found

https://smile.amazon.com/Powermaster-478021-Alternator/dp/B003EOZDUQ/ref=sr_1_3?keywords=cs-140+alternator&qid=1559264601&s=automotive&sr=1-3

and I don't know if this one takes one or 3 wires. I might be coming across as complaining or a cranky old man but that's not my intention. I appreciate the help, I'm just trying to figure this out before I actually make a purchase because $150 to $200 seems like a lot of money for an alternator to me.

[babywag]

i believe powermaster sells a delco that bolts right in.
also there are 60amp? stock alternators
i put one in my cj5

[PlasticBoob]

I don't understand exactly what installing a CS-130 would entail, do they use the same 3 wire setup? None of them seem to say what wiring setup they have. Will I still be able to hook up my amp light?

Yes, it is a 3 wire setup, but apparently some people run it in a 2-wire or 1-wire configuration.

I like my amp light and I like it to work. I don't like having a bunch of aftermarket gauges cluttering up my cab. I don't really mind cutting and modifying the alternator but I really need to know that this will work before I do it.

I'm going off of memory here, but yes you should be able to retain your amp light. IIRC, the CS-130 NEEDS either an indicator light or a resistor in the regulator circuit in order to function properly in some vehicles. I skipped the light and just bought the GM resistor pigtail. Wiring a CS-130 is not difficult at all. Here's a thread from another forum that discusses wiring. I put the sensing wire way far back in my wiring where there is a voltage drop, so the alternator pumps out a little more voltage. I get around 14.4v at idle in gear.


I can only tell you what worked for me, and that was to get a Duralast Gold CS-130 from Autozone, part #DLG1352-5-11 and Bulltear mounting bracket.

The alternator itself is for a 1988 Chevy Truck K3500.

I had to swap the pulleys and drill out the lower mounting boss just a hair, because the Jeep's bottom mounting bolt was too large. Believe me, the difference is so small that no one at the parts store would notice this for a warranty claim. I don't think this is a problem on the newer FSJs, because that's the alternator a lot of people on this forum recommended and I didn't hear anyone else bring up that issue.

I don't know if we both had the same type of bracket, but I got fed up with trying to figure out the stock mounting setup and decided to just get the Bulltear alternator bracket. Yes, it is costly, but in addition to allowing the alternator to bolt right on and adjust easily, it moves the alternator much higher up to a safer position, closer to the intake manifold. I see that as a major benefit if you plan on doing any wet off-roading or heavy wet weather driving.

I don't have access to my notes right now, but you also need a different belt. I will post the part numbers I find when I regain access.


The CS-130 swap is a "buy once, cry once" sort of deal and I haven't had to touch anything on my setup in over 11 years.

[Crankyolman]

So I've been digging around about this issue. Powemaster makes a 100 and 150 amp alternator to replace the Motorola, P/N 8-36101 & 8-36141. ( https://www.summitracing.com/parts/p...p/model/j-2500 ) BJs has it also ( http://www.bjsoffroad.com/150-amp-Po...nt_p_1744.html ) but my last buying experience from BJ's kind of made me not willing to buy from them unless there is no alternative.


Does anybody know if this one is like a SI or a CS? or will any Powermaster put out clean electricity? I have no clue about that stuff and really don't know if it is any better or worse than anything else. About the only thing I do know is they say it is 1-wire only so I don't know if it will let me use my dash light or not. I just sent an email to Powermaster to ask about that.

[babywag]

looks like delco si with custom front case half.

https://static.summitracing.com/global/images/instructions/PWM-alt8_jeep_up_si.pdf

instructions show charge indicator hookup