Cs-144 Alternator Rebuild & Questions

Indycars

Administrator
Staff member
I've never heard of grounding the back case on an alternator until today. But the AlternatorMan
says it very important.

Anyone familiar with this need to ground the back half of an alternator case ???

Page down toward the bottom of the comments to see the AlteratorMan's comments.


I've got my alternator all apart since it's only charging the battery at 11.8v to 13.5v and suspect the
voltage regulator is bad. Everything else can be tested with an ohm meter and diode setting on your
DMM, but the regulator needs special expensive test equipment.

FP01_AlternatorCaseOpen_02428.jpg
FP01_AlternatorCaseOpen_02426.jpg

After running all the internal components thru the parts washer.

FP01_AlternatorInternalComponentsCleaned_02439.jpg
.
 
Last edited:
While I'm waiting on parts I decided to fix the lack of Glyptol on the rotor windings. Since the rotor turns
2.5 to 3.0 times the engine rpm or about 16,00 rpm, I wanted some better protection against the winding
coming loose. Brian didn't completely cover the winding with Glyptol when he built the alternator, but he
did use Transpo parts like he talked about.

FP02_RotorUnPainted_02446.jpg

FP02_RotorPainted_02451.jpg

FP02_RotorUnPainted_02443.jpg

FP02_RotorPainted_02452.jpg


I ordered a voltage regulator and brushes from Quick Start Alternators. I don't think the brushes are needing
replacement, but to be on the safe side I ordered them anyway while I was paying for shipping.

FP02_VoltageReg&Brushes_02458.jpg

https://store.alternatorparts.com/partnod4081.aspx
upload_2020-9-30_16-1-45.png

https://store.alternatorparts.com/cs144-series-brush-holder-assembly.aspx
upload_2020-9-30_16-2-27.png

Anyone ever run a ground to the back half of an alternator case ???

.
 
http://bzerob.com/library/gm/gm-SI-upgrade- to-CS-alternator.html

GM Upgrade to a CS Alternator
Why go through the trouble? Well, the GM SI alternators are easier to get and have higher outputs.SI is short for Systems Integrated which means the regulator is inside the alternator case. The CS alternators are even better!
The GM 10SI Alternator
All 10SI have three terminals (including those with a 1 wire regulator).

  • The large BATT terminal which gets connected to your battery positive and a dual terminal connector. (available at any autoparts store)
  • The 1 or R - Relay Terminal. (Marked with a 1 and R on case) This terminal provides a pulsing DC signal which varies with engine rpm. The voltage is half system voltage as measured with a voltmeter. This terminal is used to connect to the dash warning light, or used as a tachometer connection For the warning light, a lamp is wired in series with a switched voltage source. During normal operation the lamp stays off. If the regulator is damaged, the 1 terminal provides ground, and the warning lamp will light. This terminal is also active on 1 wire regulator equipped 10SI alternators.
  • The 2 or F or Field/Sense Terminal. (Marked with a 2 and F on case) This terminal is used to excite the 10SI into operation. (3-wire 10SI) It is connected to the battery positive. For simplicity you can connect the 2 connector pigtail directly to the BAT terminal on the alternator. The terminal is present on 1 wire regulators. Used only for those that require the stock connector to fit snugly. If you are converting from a 3 wire 10SI to a 1 wire regulator you can hook up all your stock connectors, and run it as is. However, that's wasted money unless you plan on cleaning out some wiring under your hood.
Typical SI Sources

  • Delco 10SI Series (61 amp/Single V groove pully) - Delco 1105360 / Lester 7127,7128 and 7282 used on 85-73 GM 4, 6, 8 Cyl
  • Delco 12SI Series (78 amp/Single V groove pully with M8x1.25 threaded ear) Delco 1100250,1105370,1105372 / Lester 7271, 7272,7272R and 7273 used on 83-89 GM 4, 6, 8 Cyl.
  • Delco 12SI Series (94 amp/Single V groove pully with M8x1.25 threaded ear) Delco 1101308 / Lester 7294 used on 84-87 GM 4, 6, 8 Cyl.
  • Delco CS130 Series (100-105 Amp /Single V groove pully) Delco 1101229, 1101275, 1101292 / Lester 7808, 7888 used on 88-90 5.0L Buick Estate Wagon, Cadillac Fleetwood Brougham (RWD), Chevrolet Caprice, Oldsmobile Custom Cruiser and Pontiac Safari.
  • Delco CS144 Series (140 Amp/6-Groove Pulley) Delco 10479891, 10480201 / Lester 8112 used on 93-96 5.7L Buick Roadmaster, Cadillac Fleetwood Brougham (RWD), Chevrolet Caprice and Chevrolet Impala 5.7L
If the one wire alternator is for cleaning out wires, you only need to retain the BAT wire. The 1 and 2 terminal wires can be eliminated. Don't be surprised to find that the Field wire only goes a short way into the harness and spliced into the BAT wire. The 1 wire regulator comes with a dust plug for the 1 and 2 terminals.

AC Delco wiring package 1870921 (for those 6 to 12 volt conversions) for wiring up a 10SI. This contains the terminal connector AND an extra resistance wire pigtail to connect to the ignition system (don't use a ballast resistor if you use a resistance wire). Also available is an ammeter package (1965400). Another piece (pn #8077 and 8078) is available from AC Delco for upgrading to a CS style from an SI. These SI-to-CS adapter plugs have a Molex connector to fit the existing wiring harness SI style connector, and the Delco Weather Pack connector to fit the CS-130 and CS-144. The AC Delco #8077 is used if you have a lamp on the dash and the #8078 has a load resistor for use with no lamp.

Alternate part numbers for the dash light version pigtails are Haywire P/N 2110 / Painless Wiring P/N 30707. General Motors P/N12102921 / Pico P/N 5331 are for no dash light installs.

Pulleys can be interchanged between the old externally regulated and the 10SI/12SI/CS-130, and even with the old externally regulated FORD alternators.

Always use a voltage gauge to monitor your charging system.
Don't expect your alternator to do anything for you at idle speeds. Alternator output increases with rpm, even a 100 amp unit won't put out much more than a 63 amp unit at 1000rpm.
The CS130 / CS144 Alternators
In 1986 GM introduced the completely new, 105-amp, CS130 Delcotron alternator (CS130 = Charging System with 130 mm diameter stator) because the SI series alternators could not keep up with the increased electrical demand and because overdrive transmissions were lowering engine and alternator rpms. The CS130 weighs less, is smaller in diameter but uses the same 6.6" mounting-hole, center-to-center distance, uses less internal parts, has a better voltage regulator system, has increased durability and is less noisy (audibly and electrically) than the SI alternator it replaced.

There is also a 120-amp, CS144 version if you need more output because you're running large amounts of electrical equipment in your vehicle such as high-powered stereos.

Typical CS Sources

  • Delco CS130 Series (100-105 Amp /Single V groove pully) Delco 1101229, 1101275, 1101292 / Lester 7808, 7888 used on 88-90 5.0L Buick Estate Wagon, Cadillac Fleetwood Brougham (RWD), Chevrolet Caprice, Oldsmobile Custom Cruiser and Pontiac Safari.
  • Delco CS144 Series (140 Amp/6-Groove Pulley) Delco 10479891, 10480201 / Lester 8112 used on 93-96 5.7L Buick Roadmaster, Cadillac Fleetwood Brougham (RWD), Chevrolet Caprice and Chevrolet Impala 5.7L
The 105 amp version size is close to typical SI alternator. So you can use the original brackets. Typical SI alternator is only 63 amps and at higher RPM's than what the CS's need. In other words, at idle, the CS is putting out, where as the SI is just spinning.

The 105 amp CS130 alternator can be found on late-80's GM truck or full size car with mounting ears that are 180-deg apart. Most will come with a serpentine belt pulley so you will have to change over your pulley if you are still using a V-belt.

The flange for the tensioning bolt and the alternator bracket are tapped for metric bolts so you will need to get 8 x 1.25mm bolts. The alternator bracket may need to be modified and you will probably need a couple of washers to take up the space between the alternator bracket and the new alternator.
Most of the connectors for the CS alternators are four wire but will only use two of them and the wiring is the same as the SI.

CS series wiring pin-out:

  • S = Heavy gauge wire to the battery supply usually red (loop back to post on back of alternator).
  • F = small gauge brown wire - not used.
  • L = Small gauge brown/red wire - comes from the dash light and energizes the alternator.
  • P = Small gauge brown/white wire - not used.
CS Install Note: The switched 'light' (terminal 1 on SI or 'L' on CS), must have 12V switched power with between 35 and 350 ohm resistance *** If below 35 ohm, the CS units will not work! *** That resistance is normally the bulb! If you try to be "custom" and use a LED, there isn't the correct resistance and the alternator will not work correctly! You can't just by-pass the light! You may need to add a resistor to this lead. Some documentation suggests that a switched power source can be connected to the 'F' terminal instead, where there is supposed to be an internal resistor.
 
Last edited:
When I replaced the Voltage Regulator last September 2020, it never did charge right. Everything seemed
to be working thou, but I realized now that it was because I always charged the battery during the period when
I wasn't driving. The volt meter always read in the 12 volt range, but in hindsight it should have been reading
over 14 volts all the time.

I was looking at buying a new one this morning, but decided to pull it and test the diodes again first. When
I pulled the rotor out of the back half and ONLY one brush popped out, I knew there was a problem.

Turns out when I put it together last September I got the brush wired jammed in the brush holder, see pic
below. I'm guessing the VR was bad and needed replacing, but then I introduced another problem. As they
say "You can't win for losing."

FP01_BrushWireJammed_02672.jpg
.
 
Guess adding a wire wouldn’t hire but the case of the alternator is bolted to the motor and that is grounded.
 
adding a short 10 ga- 8 ga copper wire to the alternator case to the block sure won,t hurt
https://www.jegs.com/i/JEGS/555/10201/10002/-1
555-10201.jpg

https://www.jegs.com/i/Powermaster/713/37864/10002/-1
adding a 200 amp alternator also helps

http://garage.grumpysperformance.co...eed-a-damn-good-high-output-alternator.16145/

https://www.dbelectrical.com/alternators/


http://www.jegs.com/p/Powermaster/Powermaster-GM-CS144-Style-Alternators/1534945/10002/-1

 
Last edited by a moderator:
While I had the alternator out, I pulled the radiator because I thought I had a leak in the upper
tank. But when I had it checked (while I watched) they could not find any leaks. This is the
second time, last summer I had it out and checked for leaks but they could not find any.

This last time the guy noticed a indention in the upper hose connection, so that's what we think
was causing the leak now. He had a tool he could stick inside the connection to make it round
again. Kinda reminded me of a exhaust pipe expander.

FP03_UpperRadiatorHoseConnection.jpg

Domino effect is now in working!:)

Since the radiator was out I needed to fix the allen wrench that broke off in the water
pump pulley.

FP03_WaterPumpBoltRepair_02675.jpg

FP03_BrokeAllenWrench_02682.jpg

I think I put too much torque on the wrench for it's size. You can see the twist on the right side above.

So I got setup to weld a nut to the end of the flat head. Question, can you weld to a black oxide
finish ???
My first attempt did not work, it just twisted off. For the second attempt I filed the surface
so it was shiny, then I welded the nut to the flat head, this worked.

FP03_WaterPumpBoltRepair_02679.jpg

FP03_WaterPumpBoltRepair_02680.jpg .
 
Thanks Grumpy !

Is there a problem MIG welding to a black oxide surface ? My first attempt was done with
the nozzle too far from the surface to be welded since it was down inside the nut, I positioned like
I was welding on the close side of nut . On the second attempt I had the nozzle almost touching
the nut.
 
https://www.finishing.com/75/78.shtml
I have rarely welded black oxide finish bolts, but don,t remember any real issues
but read the link above

 
Last edited:
Back
Top