So recently my lights died when driving (at night!) an when I got home it turned out the battery was not charging - also I then realised the charge light was on (its covered by the tacho but I saw it lit when I had a proper look).

So first off I knew the car had already a solid state regulator (so I assumed it was ok as it was newer than the 32 year old Alt). So I got a new alt and hooked it up (old alt had #OOPS#ed bearing/brushes and the coil read a little on the low side - possible short).

Once I started it I checked the battery voltage (same as when the engine is off) so I knew the damn thing wasnt charging.

Next I performed the Regulator bypass test - I powered the field coil from the +ve battery terminal and when the motor was on you could hear it bog down under load and the mulitmeter showed it was in fact charging.

I also checked the continuity of the cables between the reg plug and the back of the alt and all of them were ok. I could measure 12v in the plug when the igntion was on and I could also power the charge light by shorting it to ground.

Everything pointed to a buggered reg seeing as the cables and alternator were ok.

Next day I got a new reg. The guy in the shop said they had trouble with the electric regulators and I then brought the mechanical type one (brand new). The plug on it was identical to the original and the wire colors all matched up. Once I installed it I started the car and the charge light was still on! Even the DMM across the bettery showed no charge!

What on earth is wrong? Has anyone repleaced both the alt and reg and still had this trouble?

Can you confirm that the replacement alt that you fitted is not an IR [internally regulated] type

Yes this is very common
1. Using wrong alt marked L &S for the T-connector
2. Aftetmarket regulators. Many are bad from brand new, both electronic or mechanical.

Definatley externally regulated (has field and neutral pins on it).

Fixed the problem though!

What got me was that I checked everying and it showed up ok - so whats causing the problem? Magic lol?

What happend was I rechecked the reg socket pins on the harness and the feild/neutral/earth/active cables had continuity and were properly connected. The light pin had 12 volts (ready to be grounded by the reg when no charge).

However, the ignition pin had no power! I checked the fusebox and there it was - blown IGN fuse.

What happened yesterday was that after checking the socket and working out EVERY pin was as it should be , I assumed that the regulator must be broken. As a last resort I tried to manually trigger the power transistor in the reg (to see if it failed) but as it turns out I dont know my TIP107 transistor pin outs and I blew it up (no loss, the reg was rooted anyway).

This also blew the ignition fuse!

Anyway, the car runs, the battery charges and on idle I get 14v and 14.2v with the high beams.

And after the test drive the datto is scary fast, might do a write up sometime.

yes i would like to hear about your turbo gear.

I dont have a camera lol, I'll try to borrow my mates soon.

A summary of the car is:

1979 Datsun Sunny B310

A12 motor circa 1979 - stock internals
IHI turbo - rebuilt/custom carbon seal mod
Mikuni HSR 45 carburettor - custom machined needle and jets
Apexi Power Airfilter
18 psi (20psi on over boosting)
Electronic locked distributor 25* (can run 30* if I back off if it knocks on occasion)
Custom turbo mani
Custom dump pipe
Exhaust to suit
Custom Inlet
Custom charge pipe (with H2O injection setup)
Water injection (650psi pump, 5L tank, switches on at 8psi)
GT40R coil
Gilmer drive
300zx radiator (I cut/welded part of the tank to clear the chassis rail) It's huge, only 5mm clearance all around, 10mm from the bonnet and 55mm thick!

60 series 5 speed
Rebuilt - all bearings and seals changed, re shimmed.
I made custom washers/bushes/ball socket for the gearstick so that there is no free play/slop and gives awesome gearshift performance.
Custom crossmember
HD full face clutch

Suspension is lowered
King springs all around
New bushes all around
Custom strut brace
Monroe Gas GT shocks all around
Stock wheels for now (I'am buying ROH Shift R's and 195/50R 15 tyres - adrenalins Re001)

Other work done is strip the front end and POR15 the engine bay/undercarridge to fix minor surface rust (I'm just parranoid).
Guages - tacho, boost, WBO2, turbo timer
Synthetic fluids all around
Immobiliser
Klaxton horn!!!

And finally paint! Everything I take off is repainted while I work on the car, grit blast, prime and paint. That included, all suspension parts, brakes, rims, undercarrige parts, manifolds, turbo, pipe work, everything!

All fabrication - TIG welding(stainless/aluminium), fittng, machining, wiring, design and tuning is done by me at home.

Work left to do is the wheels/tyres, paint and interior - then I guess its a showcar lol.

I will get a proper project build page done soon with more info, lots of photos and a bit about me.

sounds fantastic, i like the idea of painting everything, i started doing it with my control arms and castor rods when i changed the bushes but only used rattle cans as i dont have a compressor yet.

definitely interested in your firm gearshifting techniques (lol) i hate my sloppy gearbox

your setup sounds porn mate!