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Datsun 280Z Voltage Regulator Conversion
(As performed on a 1977 280Z)

  Craig Borden  
 

None

 

GM Delco-Remy Alternator Conversion Information

LR160 specifications and performance numbers here

Datsun LR160 Alternator Connection Descriptions

COMPATIBLE ALTERNATORS*
*Pulley swap & wiring connectors mods may be needed, alternator alignment and mounting are bolt-up
Year, Make and Model Output Rating (amps) Mods
'78 Datsun 280Z LR160 60A none
'79 - '83 280ZX 60A none
'81 - '83 280ZX Turbo 70A none
'81 - '85 720 Pickup 60A ???
'85 Nissan 300ZX 70A wiring
'85 Nissan Maxima "A" 70A wiring
'85 Nissan Maxima "B" 80A wiring
'95 Nissan 240SX 90A wiring/pulley

PicA

PicB

PicC

Cut off the wiring stub from the old voltage regulator or, if your regulator is still good, find an old one and use its wiring stub. You may desire to do away with the stub and hard wire the wiring harness but it will be best to see if you like the new arrangement before making such a permanent change (PicA)

(PicB) is a view of the engine side of the external VR connector which is the female receptacle. The terminals are numbered for your convenience. Remember that you will be wiring the male plug so make sure that you are splicing the correct wires. Double check yourself before you start wiring.

Wiring
With the old VR connector plugged into the engine harness connector, there are six different wires:

Connector Position WIRE COLOR New Connection WHERE IT LEADS (Refer to PicC)
1 white/red connect to 5 goes through the charge lamp in the dash to a +12V ignition source at the fuse box
2 white NOT USED battery connection - constant +12V
3 yellow connect to 6 goes to "S" connector on alternator
4 black NOT USED goes to "E" on alternator - ground
5 white/black Connect to 1 goes to "L" connector on alternator
6 white/blue Connect to 3 a true +12V ignition source

That is it. The charge light will work correctly and the remaining two wires (white and black) are unconnected and unused. Enjoy.

The Dreaded "Run-On" Fix by DIODE installation; 240Z and 260Z Owners ONLY
(contributed by Dave Chapman)
The 240Z and 260Z cars must be wired up a bit differently. The common problem is that the wiring is done correctly but the result is a car that won't shut off even when the ignition switch is off and the key removed. This is because the charging system is in a "feedback" loop and can't stop once it is going.
To solve the problem, a diode must be installed. A diode is basically a one-way valve for current and will not allow the "feedback" problem occur. The diode can be found at Radio Shack and the most common is specified as 1N5402.
The cathode end of the diode (end with a white stripe) should be connected to the switched 12V connection (connector position "1" above). The anode end of the diode should be connected to the "L" terminal (connector position "5" above).

Results

My gauge used to read high all of the time and always had. If you think your gauge is malfunctioning, see if you can adjust it first.
The alternator charges fine and I have had no problems with the conversion. This replacement is great because those factory mechanical regulators are getting hard to find and will be extinct shortly. The aftermarket, solid state external regulators never seem to work right (one actually caused my clock to smoke) so this mod solves that problem.