'75 280Z alternator upgrade

[75er]

Has anyone out there done the 280zx alternator upgrade on an early 280z? I've read various threads online about different wiring needs between 240/260Z and a 280Z, but some of the difference seems to be related to the 280z having a voltmeter rather than an ammeter on the dash - my 280Z still has the ammeter so was hoping someone out there might have done the swap on a similar car & figured out how to connect it all up!

 

[MCBladeRun]

Hi

Did you ever figure it out?

I was curious as no one has replied to you. A voltmeter should pick up the voltage between the -ve and +ve or possibly the +ve and the 0v ground (I'm new to this, don't quote me)
An ammeter should consist of 2xwires with a detecting coil around the +ve wire leading to the battery (I think?)

Martin

 

[johnymd]

The principle of the conversion should be the same for any zed going from external to internal regulator. There are quit a few writ-ups on this.

Basically it is just a case of Joining the L (lamp) and S (sense) wires so they go straight to the alternator terminals rather than the external regulator then linking up another couple.

 

[jonbills]

+1 I can't remember the details but it was easy, after spending a while looking at the wiring diagrams for cars with ammeters and voltmeters. I swapped a voltmeter into mine and I think I only jumpered a few pins on the old regulator socket.

 

[AliK]

Does this help?

http://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html

And 280z wiring diagrams here ...

http://www.atlanticz.ca/zclub/techtips/electrical.htm

 

[johnymd]

I fitted a mx5 mk1 alternator to my zed last week. The wiring is exactly the same as the 280zx and most internally regulated alternators. Basically it has 3 connections: main power out (which you can connect straight to the starter terminal as it’s so close), L connection (which goes to an ignition feed via a charge lamp), and S connection (which goes to a live connection near the fuse box and senses the battery voltage).

I have just bought another Mazda alternator as I can’t seam to get the charge light to come on. It comes on when I short the L terminal wire to earth but not when connected to the alternator. So I’ve taken a punt on a brand new Mazda 323 alternator. It was only £32 which seams about the going rate. I’ll swap it today to see if the light works now. The old one charges ok but it would be nice to have the light working. I’m not using the ammeter but do have a cheap little volt meter I’ll stick somewhere.

 

[MaximG]

The delete plug that you get to do away with the external regular has a resistor included in it.

 

[johnymd]

What’s the resistor for? A load for when there’s no lamp? I recall fitting a diode once the stop the engine running on.

 

[Rob Gaskin]

Guys comments please (I know we have a few amateur [ not ammeter] electricians).

My 240 has the 280ZX alternator. Also it had some additional wiring (and fusebox) for rally related 'stuff'. The power for the second fusebox came off the 'swtiched' terminal of my battery master-switch (between battery and starter).

I have removed the additional wiring and I'm going to improve it.

First of all the ammeter - this measures current from or to the battery and is wired after the starter. So as my additional wiring is before the starter I assume it doesn't measure any current drain in those circuits (in the same way as it doesn't measure starter current). However if with the alternator charging and the battery 'flat' would it measure that load too because it is supplying it through the ammeter from the alternator? I'm not in a position to physically check it atm.

Next I'm thinking of fitting a Voltmeter with charging light (like my 260Z). Where do I connect this meter to and does it require a separate 'charge' signal from the alternator (for the 'charge' light)?

Thirdly I have read that the old-style fuse boxes can overheat due to poor connections. Has anyone experienced this and have they fitted a 'blade' fusebox?

 

[Rob Gaskin]

Sorry but another topic:

My battery master-switch is fitted in the +ve lead to the starter. That means I have this lead running through the bulkhead and unprotected by a fuse. It has been suggested (by a member) that in this case I should fit the master-switch in the -ve lead.

Comments please.

I do realise that many competition cars have the battery in the car and run heavy-duty power leads through the bulkhead.

Realistically I'm far more likely to short the battery when using a spanner on the +ve terminal - really silly design! Always remove the -ve first.

 

[toopy]

Realistically I'm far more likely to short the battery when using a spanner on the +ve terminal - really silly design! Always remove the -ve first.

I think that answer's your own question Rob

It's personal choice really, but the reason mine is on the Neg is because that's what it advised in the instructions, the happy coincidence being you can faff about with tools by the Pos terminal with no fear of sparks/shocks etc with the earth fully isolated!