How to Convert 240Z to Internally Regulated Alternator

[Arne]

Stacy, I've never done this on a 260Z, nor do I have access to a 260Z to see what needs to be done. So I'm afraid I can't help you on this.

[SteveJ]

Hi Arne my name is Stacy I have a early 1974 260z and I want to upgrade to a 280zx alt. which I do have I keep finding info for a 280z but not for the 260z. Any help would be appreciated my home e-mail is candss4@yahoo.com if possible I can call you all I need is a contact number. Thanks in advance Stacy

Stacy, are you looking for the plug-and-play adapter, or are you just looking for information on converting to the ZX alternator?

[74260z4me]

Steve; I already have a 280zx alternator and have extra plug ends I will get whatever else I need to to it right. I have read about the 260z wiring being a little bit different. From the pictures I have seen my plug from the voltage regulator is different, and I have a fuel pump at the fuel tank and something about a interlock any help would be appreciated. Thanks

[joker72z]

Why don't you guys just buy the new alternator from Z Specialties in Washington. I bought the 105amp internally regulated alternator and it's just plug and play...that easy. PLUS> You get better amperage at idle and can easily run wipers, blower, CD and lights without everything going dim.

Check it out

[dogma420]

well joker72z, for one thing, I paid $40 for a new alternator, and many others can get this upgrade for $5-10 from a pull it lot...that's why. It's essentially just 2 wires spliced in, at least for a 240z. I have too much juice now, it's just great compared to the stock 240z alt.

When it's this cheap, why do you need to spend $100 or more for more amps...most on here don't need honestly that many amps.

74260 -- I don't have any wire diagrams around, but if you look at your wires that connect to your alternator (never mind the connectors) are there the same wires as in the diagrams for converting a 240z to this alternator?

Wires with the same colors more than likely get spliced together--you'd bypass the external regulator, and make sure you add the diode like in the conversion instructions, so your car turns off with the key (and doesn't continue to run).

Feedback...need more info man.

[troyz]

I have an early 260z and I'm upgrading to the zx alt. I have done the wiring as described for the 240z and when all complete I turned the car in the on position and I get a clicking from my fuel pump I believe. I heard theres something different that has to be done for the 260, but I can't find it anywhere. Please can someone help me so I can get it running and check out the benefits of the new alternator. Thanks- Troy

[dogma420]

260z people-- us 240z people can't help with no information....there isn't an obvious answer that we can just say 'oh, here is your answer....' tell us what you did exactly and maybe we can help...just wanting an answer isn't going to get you anything. sorry.

Troyz-are you saying that your wiring went exactly like a 240z? If so, I've done the conversion, and it should start no problem--I didn't have any issues, and from the instructions that can be found on this forum site, you shouldn't have any issues either. I would double check your work. If something is even a little bit different than the 240z instructions, please explain what was different, then maybe we (I) can help.

[troyz]

It all seems to be the same, but somehow the fuel pump is connected. I don't want to start the car until I get this fixed. I may just be able to disconnect the electronic fuel pump and run just off the mechanical. I didn't even know it had an elec fuel pump until this happened. I'm hoping someone in the z world has done this conversion for a 260 and can help. Thanks- Troy

[zcarnut]

On the 260Z there are two fuel pump relays in series with the rear-mounted electric fuel pump. One of these relays will not allow the electric fuel pump to operate when the engine is being cranked over when starting. I can't imagine the purpose of this "feature", but since the stock 260Z also has a mechanical fuel (like the 240Z) you will still have a supply of fuel to the carbs when cranking.

The other relay is to shut off the electric fuel pump if the engine stops rotating. This is a safety feature in case of an accident where you might rupture a fuel line. Although the engine may stop, you would not want the electric fuel pump to continue to pump fuel.

This relay requires an electric signal input so as to be able to determine whether or not the engine is actually rotating. On the early alternators (with the external regulator) there is a voltage induced at the "N" terminal of the alternator connector when it is rotating. This is needed to operate the "cut out" relay in the external regulator.

On the 260Z Nissan also uses the voltage at the "N" terminal to operate one of the fuel pump relays. (This voltage signal is sent it to the seatbelt interlock module as well.) This is done via an electrical connection off the external regulator (which has it's own connection to the "N" terminal of the alternator).

So, when you eliminate the early alternator and it’s external regulator on the 260Z you eliminate this safety feature. I don't feel comfortable instructing someone to disable this safety feature so this is why I never included the 260Z in my “How to Convert a 240Z to Internally Regulated Alternator “ instructions.

On my 260Z I elected to feed the electric fuel pump relay with the switched 12V (as you have done) so that the electric fuel pump operates whenever the ignition key is in the ON position. I have triple carbs and I like being able to prime them before starting the engine.

It is probably possible to design a circuit that would have an "engine rotation" output signal when using the later internally regulated alternators. I just never got around to doing this.

On the later Z cars Nissan used a special oil pressure sending unit (with two terminals) that supplied a voltage when the engine was rotating and therefore generating oil pressure.

[Quinn'Z]

What if the white wire always has power as in my case it does and i'm not sure why. My poor car has had 38 years of rewiring by whom ever. I tried running a wire from ign to K and S straight to battery and it started smoking. Any advice. Did I miss something?

[SteveJ]

If you can use a multimeter, I should be able to help you, but not until I return home.