Back on the Road: 280z Alternator Upgrade

A very common issue with the Datsun 280z is the alternator’s external voltage regulator. The voltage regulator on the 280z is mechanical and very prone to failure. Now a days, alternators are internally regulated, and have a very long lifespan. Here, i’ll detail how to upgrade that alternator in the 280z, and wrap up why my car died in the middle of the freeway.

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What you’ll need:
– 12mm and 13mm socket (or maybe even 14mm depending on the bolts you have)
– 1983 Nissan / Datsun 280zx alternator (from Amazon BBB 14592, or O’Reilly’s Ultima #14592)
– wire cutter

What you’re doing:
We’re replacing the old 280z externally regulated alternator with a newer, internally regulated alternator designed for a 1983 280zx (it’s available and off the shelf).

See below: old and new alternators. I honestly don’t know if mine was original because several sites mention the OEM 280z alternator had smaller fans. In my case, they were pretty much the same. Mind the images..I was doing necessary repairs at 11pm. hooray.

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So why did my Datsun 280z die in the middle of the road? Why did the lights go dimmer and dimmer before then? Why was the engine running rough and eventually sputtering, choking to silence? Well, the alternator wasn’t doing it’s job – it wasn’t providing power to the system, so it was relying on battery power. And just like a toy car, when the battery starts to run out, all sorts of things happen. Lights go dim because there isn’t enough power. Engine acts up because there isn’t enough power to ignite the spark plugs. Ah! So regardless of whether it’s the regulator or the alternator, we’re doing the full upgrade, never having to worry about a failure in a mechanical switch.

You can get a 1983 280zx alternator from your local parts store fairly readily. I got mine from O’Reilly’s Autoparts for $46.00 – Ultima #14592. Equivalents are: BBB Industries 14592 and Premier Gear PG-14592.

1) Detach power – remove cables from the battery, so there’s no power to the system

2) Remove the wires from the old 280z alternator and remove the alternator itself using the 13mm socket wrench. It may help to take a picture of the alternator just prior to removing the wires.

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3) Install the new alternator, and reattach all wires

4) Locate the voltage regulator, which is just behind the metal plate that the wire fuses are mounted to. Un-attach the 6-wire connector.

5) Depending on your year 280z, use the chart below to determine which colored wires to jump. Regardless of color, wires 1 and 5 are to be connected, as well as 2 and 3. You actually have several options: 1) cut / connect wires before the 6-pin connector; 2) jump the wires on the connector (like shown below); or 3) cut / connect wires after the connector. I choose to just jump at the connector in some rare chance I need the connector in the future (though, this IS one of those upgrades that is just necessary on a 280z). Here’s a chart from AtlanticZ.

Daily Datsun 280z alternator upgrade wiring diagram

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6) Reconnect the battery, check for any immediate electrical issues

7) Turn on the car to run on battery (not all the way on), and note that the charge light is lit in the volt meter dial. Turn the car on to verify the charge light turns off, and you’re registering around 14V. If the charge light is still on, and the dial is only reading 12V while the engine is running, it means something is a miss. Double check your wiring all around.

Now that your alternator is internally regulated, so there’s no more faulty regulator to replace!

 

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Yeah! all done – i believe this only took me about an hour to do. I certainly remember the sleep / peace of mind afterwards!

Helpful link from AtlanticZ: http://atlanticz.ca/zclub/techtips/alternatorswap/index.html

Let there be light!

Finally, 3 weeks later, headlights! No more slogging through the night w/ hazard lights on! No more hearing it from the wife! No more.. ok ok, what did i fix? I was able to install the new[er] 280z combo switch fairly swiftly (seeing as i’ve done it countless times before). This one, purchased from eBay, came in decent shape, and the cam switches that turn on/off the parking lights and headlights are solid. Solid. Turn on the headlights, though… nothing. Back to the voltmeter. Measured again between the terminals on the combo switch – 12.5v… but when i turn it on, it goes to zero volts. huh! a ground issue? I again make my way down the chain toward the fuse panel, then the other way toward the battery. ah ha! doh.. the fusible link looked good, but upon serious inspection (meaning trying to pull it off):

Daily Datsun - fusible link

wtf – seriously? i measured the voltage across it, and it was good! good i tell you! but probably because it was hanging by a thread, which will read voltage, but not have the capacity to hold upwards of 50A of headlight power. Just for reference, the headlights fusible link is on the bottom left (when looking into the engine bay from the passenger side).

Daily Datsun - fusible link

Until my replacement 280z fusible links can come in from Motorsport Auto’s (MSA) Z store, I just trimmed, and reattached the link – and…viola!

Daily Datsun - headlights on

and wouldn’t you know.. highs AND low beams work! huzzah!   And that’s not all. Interestingly enough there’s a bit of discrepancy in the 280z’s fusible link layout! You’ll notice on MSA’s fusible link product page, they note the use of the black fusible link (80A) for the headlights, and on AtlanticZ.ca’s site, they note that a red/brown fusible link (50A) should be used; with black being used for the alternator / ignition. See below:

MSA’s diagram:

Motorsport Auto's Z fusible link diagram

Atlantic Z’s diagram:

Atlantic Z's fusible link layout for 1977 280z

So who’s right? It would make sense that if any circuit out of the four has to have the highest rated fuse, it would be the alternator and ignition circuit. Datsun Field Service Manual (FSM) says…. huh. it doesn’t. yeah, pg BE-6 doesn’t know which one goes where. A few google searches later, you’ll notice that most images will show that Atlantic Z has it correct, the black fusible link is for the Alternator / Ignition Relay. This additional wiring diagram from CarPartsManual.com shows it clearly (even though for a ’74-’76).

Datsun-Z-engine-bay-wiring-diagram

Other supporting images show the same layout (not in favor of MSA’s diagram)…

I really like ZCurves’ solution for using the blade styled (read: more accessible / cost effective) fuses.

Yet another: http://www.atlanticz.ca/zclub/techtips/fusiblelinks/correct_fusible_links3.jpg

I guess we’ll be contacting MSA to find out what the real setup should be!

ok. time to move on to real stuff: suspension!