CS-144 140amp alternator upgrade howto

[Justins76]

My 76 originally had an 10si alt that I upgraded to a 94amp 12si. Well since I'm installing aftermarket lighting and a Mark VIII elect fan, I decided to put in a CS144 140 amp alt like I did in my Firebird. First thing to note is that alt is bigger then the SI, so in order for my stock brackets to fit it, I had to notch the top bracket where it bolts to the intake manifold. Once a notch it cut in, it will allow the bracket to swing up higher. The bottom bolt and bracket fits without mod. Also, the alt is not threaded for the top bolt. I used a 3/8" helicoil and bought a flange bolt form Ace hardware 1" long. Now both the top and bottom bolts use a 9/16" hex socket. For the wiring, I used ACDelco part number 88861073 which plugs into the stock si connector at one end and has a cs connector at the alt end. It has a built in resistor for using on cars with a voltmeter. This alt can be used with V-belts with a simple pulley change. Alt is from 94 Caprice with the 140 amp alt.

[gchemist]

Your truck will like the extra amps. I run an '08 145 amp alternator. Power windows like the extra amps. My dual LS1 fans too.

[Pyrotechnic]

Whats up with that hybrid flat/v-belt setup? Is that custom or is it some factory GM deal I've never seen?

[SBTork]

Originally Posted by Pyrotechnic

Whats up with that hybrid flat/v-belt setup? Is that custom or is it some factory GM deal I've never seen?

it looks stock. My old 86 C10 had the same style setup. A 6-rib serp belt style setup for the alt and v-belts for everything else. Odd indeed.

[beamn7]

Originally Posted by Pyrotechnic

Whats up with that hybrid flat/v-belt setup? Is that custom or is it some factory GM deal I've never seen?

Most of the factory ones I've seen with this style of belt set up is on 86 and newer. Alternator only though. Strange indeed....

[motornut]

Originally Posted by beamn7

Most of the factory ones I've seen with this style of belt set up is on 86 and newer. Alternator only though. Strange indeed....

yup my 87/88 burbs had this
here is my 88 4X4 burb

[rfmaster]

Originally Posted by motornut

yup my 87/88 burbs had this
here is my 88 4X4 burb

That's a 12-SI alternator in photo which is only slightly bigger than OE 10-SI units used in 70's and early 80's trucks. The 10SI were factory rated 37, 42, 55, 61, and 63 Amp. While 12-SI where available in 78 and 94 AMP rating. 12-SI is a direct swap for 10-SI. The CS-144 is a 'big mama' of alternators and requires some bracket rework. They were OE rated 124-145 AMP, but can be modified with bigger rectifiers for higher current output. For a stock or near stock application I use a slightly larger diameter, deep groove 3/8" V-pulley. This way there is more contact surface between V-belt and pulley. The deep V pulley also prevents belts from being tossed. The only negative is that alternator turns slower at idle, but this unit has so much current output at idle that it is never an issue, unless there large surges while engine is idling. For about 95% usage it is more than adequate with plenty of ampacity to spare (lights, winches, fans, etc)

//RF

[Pop's C-10]

So a v-belt pully would slide right on..i been wondering if it would,,thanks for tha info.

[hatzie]

Originally Posted by Pop's C-10

So a v-belt pully would slide right on..i been wondering if it would,,thanks for tha info.

However... V-belts will slip when demand increases unless you install a Cu$tom double Vee pulley set with two matched belts. Cheaper to go with the hybrid ribbed belt setup.

[James McClure]

The difference between the 2 upper brackets in how far they sit forward is about the same thickness as the upper bolt boss on the alt. I took a stud (3\8) re-taped the alt to fit that size\thread and locktited it into the alt and then installed the alt with the upper boss behind the bracket and a nut and washer outside for adjustment. It's a TIGHT fit. You might have to file a little off the alt to clear the bracket. Done to a friends tow truck years ago and its still ok. jim

[orbot]

SO the mounting is the same, can you snap a pic of the wiring on the alt. im wanting to the same thing

[rfmaster]

Originally Posted by James McClure

The difference between the 2 upper brackets in how far they sit forward is about the same thickness as the upper bolt boss on the alt. I took a stud (3\8) re-taped the alt to fit that size\thread and locktited it into the alt and then installed the alt with the upper boss behind the bracket and a nut and washer outside for adjustment. It's a TIGHT fit. You might have to file a little off the alt to clear the bracket. Done to a friends tow truck years ago and its still ok. jim

The Upper Bracket modification can be avoided all together by going to a turnbuckle style tensioner which also doubles as a bracket.





From electrical perspective The 'L' circuit must have 50 to 300 Ohm 5Watt series resistor to prevent CS-144 internal circuit damage. I do not know if commercially adapter harnesses (CS-144 to SI-10) include this resistor. It is very easy to check.

During my JY expeditions I have not seen CS-144 with V-belt pulley. Most of the time I find CS-144 alternators on front wheel drive Cady's (4.5, 4.9L) equipped with serpentine belt. If you are looking for good JY unit look for a later CS-144 design distinguished by a larger rear bearing.

Removing multi-rib pulley can be a royal pain, but this can be easily accomplished. The OE multi rib pulley is commonly installed with wedge style tapered collar. To remove pulley use impact wrench driver with 15/16" socket to remove securing nut from that alternator shaft. The nut should easily break loose assuming that shaft has not been damaged or severely rusted. Removal of the wedge collar is weird in a sense that you need to push pulley towards the fan. A fraction of an inch movement will release the tension pressure on the tapered collar. This can be achieved with a piece of pipe or a socket. I found that a 1-1/16" socket to do the job.
Set the alternator on the wood surface then insert a pipe or socket inside the pulley making sure that it does not press on the tapered collar but just on the pulley itself and then strike on the socket firmly and squarely. Once the tension is released on the tapered collar the pulley should come loose. Couple of taps on the side of the pulley may be required. Once pulley is off replace it with pulley of your choice. For V-belt applications I use Powermaster PWM-111 single grove pulley available from summit for about $8.

//RF

[blargh22]

I am about to attempt this on a '88 Suburban, that came with the 105A CS130. Basically, my alternator went bad while towing a load in a very bad area. Luckily I was able to get off the highway, and with three jumpstarts I made it the 30 miles I was away from home. I've been driving Caprice 9C1's for the last ten years and have never had an alternator go bad, which is why I want to switch to a CS144.

I really like the idea of using the turnbuckle style tensioner. Can anyone recommend where to purchase one that would be reliable? The only issue then is dealing with all the stuff that is mounted to that bracket. I believe the CS130 is also mounted from behind using a bracket. Do you basically have to lose that bracket to upgrade to the CS144?

I am going to attempt to test fit one of the CS144's out of one of my Caprices, and see if this will work, then I will either buy a new CS144, or a high output CS130 if I cannot get the CS144 in there.

[SCOTI]

One thing I don't see addressed here is a mention of wire gauge change when doing this upgrade. Swapping from a 60-74amp alt to a 140amp unit should also include increasing the charging wire size from everything I've read.

Those of you that have done the swap, what did you do?

[blargh22]

When upgrading an alternator, I would usually use those gold plated battery terminals used for car audio typically, that allow you to connect another wire to them. I would then run an additional 0 guage wire from the alternator post to the battery. This way you do not disturb anything else. A 4 guage wire is probably plenty.

[DieselSJ]

Originally Posted by rfmaster

The Upper Bracket modification can be avoided all together by going to a turnbuckle style tensioner which also doubles as a bracket.
//RF

Is that a March bracket? That looks like an awesome solution.

[hatzie]

Excellent upgrade.
AC Delco makes two adapters. My part numbers differ from the OP.

Resistor use if you have a volt gauge.
AC Delco 8078/GM 12102921

No Resistor use if you have an "idiot" light.
AC Delco 8077/GM 12083462

[Jonboy]

I got mine with a large (4-6 gauge) wire. The wire runs from the charging lug straight to the battery. I bought a couple of harnesses to adapt the original sensing wire, but never could get them to work right I ended up running a wire from a switched terminal on the fuse box with a light bulb in line (for resistance) to get it to charge correctly.

[bigwheel15]

Thanks for the write up! Ill definitely be doing this, looks like ill be doing some junk yard crawling to track down the alternator. Any idea how easy it would be to make that alternator harness yourself? Seems like a $.25 resistor and the appropriate end connectors and you'd be in business.

[rfmaster]

Originally Posted by bigwheel15

Thanks for the write up! Ill definitely be doing this, looks like ill be doing some junk yard crawling to track down the alternator. Any idea how easy it would be to make that alternator harness yourself? Seems like a $.25 resistor and the appropriate end connectors and you'd be in business.

Piece of cake! You'll you pig tail plug from CS-130, 144 alternator (source it along with JY alternator), need two crimp male tabs, 3x 470 Ohm 1 Watt resistors (metal film preferred), heat shrink tubing and some multi-strand 14 AWG wire. The L terminal from CS-130/144 requires the three resistors to be connected in parallel (net resistance 156 Ohm). This required to prevent damage to field excitation circuits inside the alternator. The S terminal is connected to main DC bus - battery block.


10/12-SI CS-130/144
- 1 - - L - Instrument cluster warning light
- 2 - - S - Remote Sense
- BAT - - BAT - Alternator output - use 8 AWG to lower voltage drop

Here is a good write-up
http://temp.corvetteforum.net/c3/zma...ternator01.htm

//RF

[toolboxchev]

Thought I would bring this back due to needing some more info. Does the CS144 have a three wire setup on the back? Any one have time for some pics.

The ones I am looking at from snappa appear to be a one wire setup and I would like to stick to a 3 wire due to its advantages in maintaining a more consistent power supply.

I know Power Master makes some nice stuff and the one year warranty from snappa leaves a bit to be desired. Preferring a lifetime warranty as things happen. Anyone have a Delco Remy part number on a 12 o clock CS 144 with a 3 wire setup?

[gmachinz]

91508 Remy on rockauto.com for $104 NEW. That's the one I use when upgrading to serpentine swaps and I always go with this one.

[gmachinz]

I manufacture the CS144 adapter bracket kit for guys running a GM serpentine setup-another option for everyone.

[Justins76]

Wow, its been awhile. I swapped over to a single serp belt setup off a Camaro and used a bracket for the cs-144 for awhile. But I no longer have the CS-144. I have an AD-244 now.

[gmachinz]

Nice!