Results 1 to 2 of 2

Thread: Datsun Z Alternator Upgrade to GM CS130 Alternator

  1. #1
    Join Date
    Sun Dec 2007
    Suburbs of Manchaca

    Default Datsun Z Alternator Upgrade to GM CS130 Alternator

    This procedure covers going from an external regulator Nissan alternator to a GM CS alternator. Finally, I recommend using a CS130 alternator. This is a collection of procedures from different sources combined into one complete procedure.
    Nissan External to Nissan Internal Alternator Swap (Putting an GM CS130 alternator in a '77 or earlier 280Z or a ‘70 –‘73 240Z)
    Why Swap?

    • The original '77 280z's build has an external mechanical voltage regulator that is unreliable and unstable with age. It is actually based upon elements that open and close many times each second due to heating and cooling. The principal is not much different than the overheat protection devices commonly used in your toaster and hairdryer. It also requires frequent adjustments of gaps much like spark plugs. The newer GM CS130 alternator incorporates a built in solid-state voltage regulator that requires no maintenance and is more stable.

    • The wiring between the alternator and voltage regulator typically is problematic.

    • The Z alternator is rated at 50A. The GM CS130 alternator is rated at 85 amps at idle and can be upgrade to 105 amps at idle.

    • The upgrade is pretty much bolt and go. Two wires need to be jumpered or spliced and that is it!

    • The CS130 unit is newer, readily available at all parts stores, and is inexpensive.

    • The CS130 unit is rock solid and the DC voltage is 14.4V at all RPMS (as measured on mine).

    • The Voltage gauge and hunting of the fuel pump will no longer waver.

    Disconnect - Negative battery terminal (Note - I repositioned my battery so that the negative terminal is near the fender).

    Here is a pic of the stock 77 alternator before doing anything (You can use it as a reference if needed.)

    Here is a another reference pic

    FYI Name plate on a stock 1977 alternator "12V @ 50A"

    Disconnect the cables to the alternator

    Remove the three bolts that hold alternator in place. I used a 13mm socket for the top bolt that clamps it to the bracket and a 12mm socket for the two bolts holding it to the engine block.

    Here is a picture of an easy way to access the lower front bolt. The rest of the work can be done from the top.

    Unclamping the carbon canister and moving it aside takes 30sec to do and helps a lot.

    Alternator removed

    Freshen contacts/connectors on the cable ends with sandpaper or scotch pad and contact cleaner (Caig Deoxit above). You only need to do the BAT, “E” and “T” contacts.

    Question: I would like to know if anyone has converted from the external regulated alternator to an internal. What wiring did you change?
    Answer: First, a little background: The 60 amp internal regulator alternator was used on the '78 280Z and then the non-turbo 280ZX. I have also seen it on the '78-'85 810/Maxima and the '81-'85 720 pickup trucks. It is marked "LR160" on the case. There was also a 70-amp version (marked LR170) that was used on the 280ZX turbo cars.
    [Note: It looks like the '84-'86 non-turbo 300ZX 70 amp alternator could be used as well, but the wiring connectors are different, so get (i.e., cut it off) the corresponding engine harness connectors as well if you get one of these alternators. I will write this up this conversion later.]
    Because I do not like to give instructions without some explanation of what you are doing (it makes troubleshooting easier), I will start by describing the internally regulated alternator's electrical connections:

    1. An "L" connection, which goes to a "switched" 12V supply. By this, I mean a 12V source that is active only when the ignition switch is in the ON position. I use the mnemonic "L" for "lamp", the alternator-warning lamp (if used) is in series with this connection. This terminal also supplies the "excitation" current to the alternator field winding at engine turn on, allowing the alternator to begin producing voltage as the engine is ramping up to idle speed. Once the alternator rotor is turning fast enough, it generates its own supply for the field winding and the current in the "L" connection stops flowing. The warning lamp (if used) goes out.

      2. An "S" connection, which goes as close to the positive terminal of the battery as physically possible. The "S" connection "senses" the battery voltage and this is the voltage that the regulator is trying to control. This connection has high impedance, so it only draws only micro amps from the battery, so it can be left connected without fear of battery discharging.
      The "L" and "S" connections are in the plug connector on the rear
      of the alternator that looks like the capital letter "T". The top
      of the "T" is the "S", and the other part of the "T" is the "L". Or in crude ASCII art:

    : ---------: "S"
    :.... | ....:
    : | :
    : | : "L"

    3. An "A" terminal, which is the output of the alternator, which also is connected to the positive terminal of the battery. This connector carries the charging current. Because of the high currents this wire must carry, it is a low gauge wire, which means it has a large cross sectional area. For safety reasons, a fusible link should be in series with this connector. The "A" terminal is the insulated threaded stud on the rear of the alternator.
    Of course, someone may ask; "Why do you need two separate (the "S" and the "A") connections between the battery and alternator?” It is because of the fact that even large wires have some resistance, and therefore there will be a voltage drop between the alternator and the battery when the battery is being charged. If the regulator sensed the alternator output (which is higher in voltage) and not the battery terminal, the result would be undercharging of the battery. Now there are alternators, which work this way, but they need a large diameter charging wire to reduce the voltage drop. The separate "S" connection is a much better method of regulation.

    4. Finally, there is a ground connection on the alternator, although the case is a good ground connection to the engine block.
    Now, the following procedure only applies to the 240Z. The 260Z has electrical connections between the regulator and the interlock module and the electric fuel pump, so it is more difficult to convert to an internally regulated alternator, but I have a procedure for it as well.
    1. Disconnect the battery.

    2. Unplug the external regulator and note the color code of the wires that are on the regulator connector of the engine wiring harness. You will be connecting some of these wires together, so get another plug from a junked regulator or cut the one off your old regulator. Now the wire colors I will be referring to are on the regulator connector of the engine wiring harness. This is because although the regulator wire colors match the engine harness with the stock regulator, I have noticed that some aftermarket regulators have a different wire color code.

    3. Connect the white wire to the yellow wire. This connects the battery to the "S" input.

    4. Connect the black with a white stripe wire to the white with black stripe wire. This connects the "L" terminal to a switched 12V.

    5. Disconnect and unbolt your old alternator. Bolt up the new alternator. Depending on what particular internally regulated alternator you use (I have seen different pulley sizes), you might need a different length belt.

    6. At the alternator, connect the white with red stripe wire of the engine wiring harness to the threaded stud (the "A" terminal) on the alternator. This connection provides the charging current for the battery. Connect the black ground wire to the alternator. Do not forget to include any bypass, or filter capacitor. Plug the two-pin "T" connector into the alternator.

    7. Re-connect the battery and start the engine. With a good digital voltmeter measure the voltage directly across the battery terminals. This is the charging voltage. It should be 14.7V +/- 0.3V, but this voltage is a function of the ambient temperature and the state of charge of the battery. If the voltage reading is not correct, then re-check your wiring. More than 15.0V indicates that the "S" connection may not be connected correctly.

    Converting from a NISSAN External to GM SI Alternator
    BTW, with regard to the terminal marks on the GM alternator case:

    GM/Delco "1" = GM/Delco "R" = Datsun "L" = warning lamp/Switched +12v
    GM/Delco "2" = GM/Delco "F" = Datsun "S" = constant +12v current sensor

    I had originally tagged this onto another thread but have completely rewritten it with updated information, hence the new thread...

    There are other posts on doing the Delco Remy (GM) alternator swap on an L6 engine, but I thought someone might want to see some pictures of what we did on all three of our 280Z's.

    Other alternator swaps have their advantages and this particular swap is not for everyone. My reasons for going with the Delco alternator were:

    1. The exact Hitachi replacements for the 1976 280z or the 1978 280z's were not in stock.
    2. The old external voltage regulator could be eliminated on the '76 Z.
    3. A GM alternator can be had anywhere, anytime for a low cost. It makes one less thing to worry about on a long trip.
    4. It was fairly easy to do with the tools I have.
    5. On two of our Z's, the bolts holes at the front of the mount were stripped and the bolts were missing. The swap solved that problem as well.

    Click here for a great website with info about the Delco Remy 10si/12si alternators.

    There are three methods of mounting the Delco CS130 alternator that I am aware of:

    1. Mount the alternator upside down. The place on the alternator where the adjustment bolt normally goes will bolt right up to the existing mount with no modification. The trouble is that some people have said that the thin metal on the alternator eventually bends.
    2. Buy or fabricate a new alternator bracket. The mounts I have seen advertised were $80 to just over $100.
    3. Modify the existing bracket. This allows the alternator to mount to the engine much as it does in GM cars.

    We went with option #3 since it seems to be reliable, inexpensive, and easy to do.

    Here are some of the tools used:

    • Reciprocating saw or hack saw
    • Bench grinder
    • Drill bits from 1/4" to 13/32"

    Parts used:

    • M10x113 bolt (HELP! Part #45636)
    • M10-1.5 hex head flange nut (Dorman 982-010)
    • M10 spring washer
    • M10 flat washer
    • 5/16"-20 bolt for ground strap
    • GM CS130 alternator plug

    Basic procedure:

    1. Remove Hitachi alternator and alternator mount.
    2. Shorten mount and drill a through-hole.
    3. Move the v-hub from the original alternator to the GM alternator.
    4. Install the modified mount and GM alternator.
    5. Change Field / Sense plug and put on larger ring-terminals.

    This is the third time I have done the swap. It takes between 2 and 3 hours to do the job if the parts and tools are all lined out.

    A picture of the new AC Delco alternator with modified mount next to the old Hitachi alternator with original mount:

    A picture of bolt and flanged nut:

    First, we removed the alternator-mounting bracket from the side of the engine and cut about an inch off the front mounting surface. We didn't want to accidentally cut too much off so I left the bracket a little long and then mounted it to see how much more needed to be cut off. I started by cutting off 1.25" (For CS130 cut 1.375” off). This placed the alternator pulley too far to the front. I used a bench grinder to do the fine adjusting. To get the alternator pulley was in perfect alignment, the bracket had to be ground so that it was exactly 1.7" deep (For CS130 trim to 1.625” deep).

    Next, the rear bolt hole needs to be enlarged and extended through the front of the bracket. The M8 threaded bolt hole needs to be enlarged to accept an M10 bolt. We used a 1/4" drill bit inserted into the rear bolt hole and drilled through the front. I worked up to larger drill bits and drilled the entire bolt hole until it was 13/32", which is just big enough for the knurled shaft of the M10 bolt. Actually, my drill set did not include a 13/32" drill bit, so I worked up to a 25/64" bit and hogged the hole out to make it large enough for the M10 bolt. For me, drilling the mount was the hardest part of this little project. It is a difficult process to keep the drill bit from grabbing while drilling without a drill press. Still, it only took about 20 minutes to get the mount modified.

    Here is the modified bracket mounted to the engine:

    Converting from GM SI to a GM CS144 or CS130 Alternator

    Additionally, the upper mounting tab of the CS130 is already threaded to accept an M10x1.5 bolt. This will may require modifying the stock alternator bracket to allow for an M10 bolt.

    All you have to do here is trim the mounting bracket the addition 1/8” to account for the thicker flange on the alternator. This makes the bracket length approximately 1.625” long. This will allow you to use any replacement alternator without modifying the case. The CS130 alternator tab is 3/4” thick.

    CS130 tab - 3/4-in. thick. The black mark shows the difference.

    Next, you will need to switch out the serpentine pulley for the L28 v-groove pulley.

    Note: On the other hand, you can purchase a small v-grove pulley from Quality Power. The smaller pulley will allow higher output at idle. They also have higher output alternators which can put out up to 105 amps at idle.

    Finally, you will have to modify the stock alternator bracket. The slot may need to be widened as mentioned above to fit an M10 bolt, but it also may need to be lengthened a bit to allow for a slightly longer belt. You may not be able to use the stock belt as it may be too short or too long and the alternator housing will not clear. I bought belts one size smaller and one size larger and returned the ones that were not needed.

    Note: With the pulley I had, I used a stock air conditioning belt for the alternator.

    Wiring changes for using a CS130

    Using the CS130 will reduce the modifications to the mounting of the alternator. A stock CS130 alternator will produce about 80amps at idle and a performance mode will produce about 100 amps at idle. Max output is approximately 100 amps for regular and 130 for the performance version. The mounting bracket will need to be shortened.

    This is the model of CS130 alternator that you will need to use in a Z. The ears are exactly opposite of each other.

    Now it is time to discuss the electrical modifications at the alternator. Never fear, these are easy. To make it stupid simple, go to an auto parts store and get a CS130 wiring harness. An electrical connector is made to convert stock alternator harnesses to CS alternators. It has two connectors, one on either end. The yellow wire is the exciter and the large is the battery sense. Simply, cut off the connector that does not attach to the alternator, attach male spade connectors to your wires to the new sub harness, and plug them in to the “T” connector and you are done!

    S-connect this right to the battery output "+" on the Alt. with a ring terminal
    F-Not needed
    L-Connect to 12V switched source
    P-Not used

    L = GM/Delco "1" = GM/Delco "R" = Datsun "L" = warning lamp/Switched +12v

    S = GM/Delco "2" = GM/Delco "F" = Datsun "S" = constant +12v current sensor

    : ------- : "S"
    :.... | ....:
    : | :
    : | : "L"
    I also recommend that you take 10 gauge or larger wire and ground the alternator to the engine block. I also recommend taking a ground wire from the battery to the engine block. I used 4 gauge battery cables to ground the battery to the body and the battery to the motor. This will improve the electrical performance of your car.

    I have noticed that I now charge around 14.25 to 14.5 volts at idle, a significant jump for me. The car idles smoother and it seems to rev better.

    Locate Voltage Regulator. It is under the bracket holding the fusible links. A 10mm socket removed the four bolts.

    Here is the bracket removed. You can see the Voltage Regulator and its inline connector

    Here is a schematic of the ZX alternator. Note the internal voltage regulator.

    • BAT (+12V battery) connection (White with red striped)
    • E (earth/ground) connection (Black) is the same on both alternators and requires no changes.
    • S (Sense) connection (Yellow) gets connected to a +12V source
    • L (Lamp) connection (White with black stripe) is connected to a +12source that is active only when the car is cranked by the starter. (You can see the node in the schematic where the L lines get power from the warning lamp when cranking and then from the alternator windings via the 3 clustered diodes when operating.)

    Electrical Jumpers
    NOTE: My recommendation is to cut the connector off the voltage regulator by cutting the wires as near to the regulator as possible. This will allow you to make the changes to the voltage regulator wires and not to the harness of the car. This will allow you to change back if you wanted to return your car to the stock configuration.

    This is the wiring to the electrical harness connector (as seen on the car when you unplug, remove, smash into bits, tramp on, and throw away the external voltage regulator)

    Here are the two connections to make - 2 to 3 and 1 to 5.

    Connect, solder, heat shrink, insulate and wrap
    Double check everything (wires correct and snug, bolts tight, fan belt snug and on correct pulleys, no tools in engine compartment, carbon canister put back and hose put on, correct jumpers at connector)

    Connect -neg battery cable briefly (1sec) and make sure there are no sparks or smoke!

    If all seems ok, connect -neg battery cable and try starting. Watch for smoke and watch the battery gauge for correct voltage and Red LED functioning.

    FYI if you have a '76 280z, the colors are slightly different:

    • The white with red striped wire on the 77 is just white on the 76 (still pin 2)
    • The blue wire on the 77 is green on the 76 (still pin 6 and unused)

    Here are the '76 connections for your convenience

    Ok, many people m still confused by what is being done to the wiring. Here are the jumper connection details for each year
    1975 1976 1977
    Connect 1-5
    (lamp to windings common)
    green & red to white & black blue to white & black blue to white & black
    Connect 2-3
    (+12V to Sense)
    white to yellow white to yellow white & red to yellow
    Note: Some 1974/5 cars only have 5 wires and will need to get switched +12Vdc from another source for the “L” wire on the alternator. We used +12Vdc from the test plug located near the coil/headlight.
    Changes Specific to a 240Z

    '73 240z Connector to VReg (Rectangular)

    I followed the instructions I found on the net and it worked perfect. Also, before you do this, do a search on this site for diode. Sometimes when you convert to an internal regulator, the car will not shutoff when you turn the key to off, this is due to current bleeding through the alternator, a diode must be placed in the circuit to block it

    Good luck Converting to an internal regulator alternator

    Note: You can use the following 240Z wiring upgrade from MSA if you do not want to set up the connector yourself.

    Alternator Upgrade Adaptor, 70-73 240Z
    Quantity in Basket: none
    Code: 12-4067

    Description: The Datsun 240Z was originally equipped with a 40-amp alternator, and a mechanical, points-type external voltage regulator. Today, many, if not most 240Z's have various electrical-dependant upgrades, like electronic ignition, halogen headlights, larger stereos, cd changers, DVD players, GPS systems, and more. The crude mechanical voltage regulator is unable to deliver a stable reliable output. That is where this Adapter Kit comes in. It is small, weather-resistant, and simply plugs into the wiring harness in place of the original voltage regulator. The diode is pre-installed and self-contained. Bolt on the ZX alternator, plug this adapter in, and you are done! Additionally, since no wiring on the car is actually changed, this upgrade is fully reversible. So if you ever needed to move the Kit from one 240Z to another, the original configuration can be restored in minutes. Then the kit can be transferred by reversing the instructions. You will need to source your own internally regulated alternator. You can also simply see related items below for our complete kit including an upgraded, quality remanufactured Bosch Alternator, for one special combined price with no alternator exchange needed!
    Model Guide: Datsun 240Z Code Guide: Datsun S30
    Year Guide: 1970, 1971, 1972, 1973
    Attached Files Attached Files
    Last edited by Electro Z; 9th February 2013 at 04:00 PM. Reason: add attachment

  2. #2
    Join Date
    Sun Dec 2007
    Suburbs of Manchaca


    If you want to do the 1 wire alternator upgrade you will need to do the following:

    The following is the information needed to order an upgraded alternator from Quality Power.

    MPN CS130
    Brand Quality Power
    Amperages Available: 135 Amp -- 105 amp idle $135.00
    Mounting Styles: Straight across ears
    Regulator Options: 1-Wire Regulator add $20.00
    Case Finish: Natural Aluminum Case
    Pulley Options: 2.5 Single V-Belt Pulley (you can pick the 2" pulley if you want peak amperage at a lower rpm)
    Output post position: Rear output post

    If you want to uses the stock wiring then don't order the 1 wire upgrade and follow the instructions in the article.

    Note: One wire alternators do not turn on until approximately 1500 RPM. At that point the voltage will jump up from around 12-12.5Vdc to approximately 14Vdc. This is not a problem as you are normally turning over 1500 RPM when driving. If you want the power to come on from idle then don use the 1 wire model but use the regular model and fool the instructions in the article.
    Last edited by Electro Z; 12th June 2013 at 11:23 AM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts