early 74 260Z alternator swap

[morbias]

I'm looking at replacing the alternator and voltage regulator with a 280ZX jobby, but everything I have read so far suggests it's more complicated than for a 240Z because of connections to an electric fuel pump relay and interlock system. Does this apply to all 260's or 74.5 onwards only?

I'm guessing the ignition interlock is a US only thing?

Also, will my amp meter still function?

 

[Mr.F]

electric fuel pump relay and interlock system

Not fitted to any UK cars, so the situation should be the same as for 240Z...

 

[SKiddell]

Its worth bearing in mind that an awfull lot of S30 info on the web is from the US, refering to US cars, our US cousins don't factor in other variants from other parts of the world.

Of course if your car is a US import then its very relevant

 

[morbias]

Good stuff, thanks guys!



I take it I wouldn't have to swap out my amp-meter for a volt-meter? Also would I have to put a diode in the circuit?

 

[Mr.F]

You will need the diode in the old voltage regulator circuit - either by the ready made plug or by making it up yourself.
Voltmeter preferred to ammeter, but the original ammeter should work just the same...

 

[morbias]

ok, thanks!

 

[Craig_260]

sorry to dig an old thread up here but im thinking of doing this to my 260z firstly id just like to ask How did you get on with the conversion Morbias? and have any of you guys used the conversion kit you can get on line?

 

[SKiddell]

Do you need a "conversion kit"? is it not just a case of

Source a 280ZX alternator (reconditioned) or any internally regulated unit with the same bolt pattern/hand
Make a diode regulator plug based on the pictures online (£1 diode from maplins and an old loom plug)
Take off old alternator and throw it in corner of garage
Take off old regulator and throw it at the cat
Fit new alternator (bolt for bolt fit)
Fit pully
Fit modified plug (plug it in)
Re fit belt

Drive car

2 hours at best

I use this setup on a fuel injected, electric water pumped, ECU'd, electric fan'd road/track/quarter mile car....its been like it for 5 years with no issues

 

[morbias]

I haven't had a chance to do this yet Craig, I know it's been 6 months already...

I bought a ZX alternator which turned out to be knackered, then found out the voltage regulator on my car has been hardwired into the engine loom to further complicate matters. And then a lot of other stuff took priority - it's sort of been 1 step forwards 2 steps back for the last few months, I'm just about losing the will to live right about now. One day I will get it done but I'm afraid I can't provide any feedback on how it went just yet!

pages worth reading:

Nissan/Datsun Z Car Voltage Regulator Conversion (has a list of compatible bolt in alternators)
http://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html


Has anyone seen the Z Specialties alternators? Apparently you don't need to rewire any of the regulator connections, not sure how that works. 105amp High Output Alternator: Electrical Z - Misc. Electrical - 15009-EPEE - Z Specialties Online Store - If we don't have it in stock, we can get it!

 

[Craig_260]

this thing i saw wasnt so much a conversion kit i guess it basically just had everything needed to be bolted on with the re-conditioned unit and the modified regulator. is the guide on here or just google?

 

[Craig_260]

I haven't had a chance to do this yet Craig, I know it's been 6 months already...

I bought a ZX alternator which turned out to be knackered, then found out the voltage regulator on my car has been hardwired into the engine loom to further complicate matters. And then a lot of other stuff took priority - it's sort of been 1 step forwards 2 steps back for the last few months, I'm just about losing the will to live right about now. One day I will get it done but I'm afraid I can't provide any feedback on how it went just yet!

pages worth reading:

Nissan/Datsun Z Car Voltage Regulator Conversion (has a list of compatible bolt in alternators)
http://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html


Has anyone seen the Z Specialties alternators? Apparently you don't need to rewire any of the regulator connections, not sure how that works. 105amp High Output Alternator: Electrical Z - Misc. Electrical - 15009-EPEE - Z Specialties Online Store - If we don't have it in stock, we can get it!

thanks for the update pal ill check those links out. did you get the alternator from a scrap yard or bought a recon one?

 

[morbias]

I got it from ebay, supposedly from a low mileage car. It looked like it had been dropped though as the pulley was bent up

 

[morbias]

Ok, I decided I've been lazy enough and should get around to tackling this conversion. So, alternator conversion take 2.

Right, so as mentioned the voltage regulator has been spliced directly into the engine harness which means I haven't got a plug to look at. Currently I have the harness unplugged from everything in the engine compartment so it's a bit easier to work on, but what do I find when looking at the voltage regulator? There's a wire coming out of the vreg that isn't connected to anything at all.

I'm assuming this is the correct pin-out for my car (this is from the '74 260Z FSM and all the colours seem to match up) and there is a white/red wire coming out of the vreg that isn't connected to anything.

I started unwrapping the engine harness to look for the white/red wire it should be connected to, and I kept going, and then I unwrapped a bit more, and then a bit more... long story short, there is no matching white/red wire in the harness at all.

Seeing as I need to connect the missing wire to another wire to do the conversion, this is a bit of a b*stard to be quite honest. In other words, I need to run a new wire to whatever the white/red wire should be connected to, but I don't know what that is, does anyone know?

Also I need to find out what the letters on the pin-out picture refer to;

L = L connector on the alternator?
IG = ignition?
F = ?
E = earth?
N = S connector on alternator?
A = Battery?

Somebody please help me!

 

[morbias]

I've been staring at circuit diagrams for the last two hours, but none of them are specific to my car. This is what I've worked out so far:

Pin 1: L - White/Red - Missing wire, it should apparently go to the charge lamp in the dash then on to +12v ignition @ fuse box
Pin 2: A - White - Alternator output to battery
Pin 3: N - Yellow - Sense wire (connects to 'N' on alternator)
Pin 4: E - Black - Ground
Pin 5: F - White/Black - Lamp connection (connects to 'F' on alternator)
Pin 6: IG - White/Blue - True +12v ignition source (whatever 'true' means)

To bypass the Voltage Regulator:
Pin 1 connects to Pin 5 (with a diode in-between)
Pin 2 connects to Pin 3

Seeing as I have an ammeter instead of a voltmeter I don't have a charge lamp. Is that why I don't have a white/red wire in the harness? If so, then what do I connect the cathode of the diode to?

[EDIT] Thinking about it, the diode would need to be connected to a switchable +12v source, which I assume would be pin 6. Is that right? I don't want to fry anything!

[EDIT 2] Looking at the circuit diagrams for internally regulated and externally regulated alternators, the main difference is that everything goes through the L connector on the internally regulated version negating the need for an IG terminal. So comparing the two, it looks like I can just use the IG wire on my harness to connect to the diode, in order to excite the alternator when the ignition is turned on. If someone with more brains than me could confirm that, then I'd be grateful.

Externally regulated:

Internally regulated:

 

[morbias]

I'm wondering -- since I don't have a charge light in the dash, do I need to put a resistor in-line on the IGN wire to get the alternator to start charging? Would 10 ohms be enough?

(IGN SWITCH)------------|10A FUSE|------------|10 ohm|-------------->|--------------F(ALTERNATOR)

Does this look right?

 

[morbias]

Just an update for anyone needing to do the same thing. Today was the first time I've been able to test the new alternator wiring and it all works perfectly -- no needing to blip the throttle to get the field going either. After calculating it properly the resistor needed is in the region of 40 to 45 ohms. Too small a resistance and you risk burning out the alternator, too much and the alternator won't charge.

I went with 43 ohms (a 10 ohm and 33 ohm resistor in series), alternator starts charging as soon as the key is turned.