Back at it again

[Dcsinclair22]

Hi all, as some of you may remember, back end of last year I decided to tackle the mammoth task of the wiring (more like a group of 100 spiders had been let lose under the bonnet) but anyway due to several reasons (mainly health problems) I put the project on the back burner, but I am back at it and once more require a little advice so here goes........  whoever wired the car up clearly either had a death wish or just didn't have a clue, I had live wires going to thin air, limited use of relays, stalks that didn't work, everything was controlled by those little toggle switches and were just hardwired direct (I think hence why the fuel pump kept blowing) talking of fuel pump to put into context how messed up the wiring was, once I stripped most of the wires out and had nothing connected, If I put a live feed direct to the high beam wire on the left headlight, the fuel pump would run, that was the final straw, lost my temper and in a fit of rage, ripped the whole loom out and completely started again, now this I'd where I could do with a small bit of advice, there was no starter relay for the starter motor and no relay for the alternator (not sure if the alternator requires a relay) but I'm about 97.679% positive the starter motor should have a relay, so my question is, what amp relay and will a standard 5 pin 40amp work or will I require a bigger 100amp 2 rod type relay, bearing in mind the starter has the solenoid built in. Anyway sorry for the long read but thought if give an insight into what I've been up to, here's some before pictures, I'll stick up some after pictures here once I've finished 

[Dcsinclair22]

Also another question regarding alternator, when I stripped the alternator wiring out, the was a brown wire from the alternator running through the firewall and splitting of in about 10 different directions, when it comes to re wiring, can I just run a positive from the alternator to the new fuse box positive to send power to my whole fusebox when the engine is running or should I just leave it with the wire running to the battery and charging the battery and all my fuse box power running from the battery? 

[IanS]

Starter solonoid is low current and will not need a relay.

Alternator main output is normally permently connected to the battery, it has 3 phase rectifiers (diodes) installed which stop the alternator discharging the battery when stopped. Second wire is to the bulb in the dash.

Normally a relay (70A?) from the ignition switch powers the live line of the most of the fuses, side lights and hazard lights have to work with ignition off and are the exception.

It does not matter which way the alternator power line runs main relay-battery or battery-main relay, the one that uses least cable is normally chosen.

[Dcsinclair22]

That's great thanks Ian, ive been reading through some alternator threads, I'll need to confirm what alternator I have (was bought brand new last year just before I got the car) as I don't have a light on the dash or behind the dash, not sure if it matters but my ignition key only acts as a steering lock, turning the key does absolutely nothing except engage lock, the car Is turned on by a silly little red key that cuts power to the positive from the battery, then I have a 4 switch 1 button panel on the dash, looks like something from top gun, so to start the car, it was turn red key (passenger side footwell) flip up a red rocker cover, flick swith up (sent power to fuel pump, push the start button ( sent power to coil and starter) and the car started, then one switch turned the lights on, another switch controlled the fan, so on, the only thing that was controlled by the stalk was indicators, (now have all lights working from stalk so it's slow progress at the moment 

[Dcsinclair22]

Or the coil was linked to fuel pump switch, can't quite remember but pretty sure that's all irrelevant 

[IanS]

Most alternators use light to give early charging at engine start but most will self start charging when engine revs hit about 2000 rpm. Once charging the alternator only drops out when stopped.

Some folk want something diferent when they build

[Dcsinclair22]

Yeah I'm back at the car tomorrow so I'll grab some pictures of the alternator, the location of the alternator seems strange to me aswell, right on the bottom drivers side where the rad pip goes straight thru the centre of the belt, so to change the belt I need to drain the coolant 

[Dcsinclair22]

[Dcsinclair22]

Ok so got some pictures of the alternator, albeit upside down and back to front pictures but I'm hoping someone can confirm, seems to be 3 wires coming from the 3 pin plug and 1 thick wire from the bottom nut, so do I just run the thicker of the 3 wires to the battery, 1 to a light on the dash (never has a light before unless it was somehow wired to one of the clock lights maybe?) and one to the positive post on the new fuse box? Or should 2 go to the battery? 

Edited May 29, 2024 by Dcsinclair22

[nelmo]

I have a similar setup but I bought the main GBS loom, so I don't know where those 3 smaller wires go to exactly.

One thing I will warn you of, in case you haven't done this already; disconnect the battery before going anywhere near that thick wire. My first alternator died and I almost electrocuted myself trying to take that big wire off without disconnecting the battery. As it was, I literally burnt a groove in the old alternator body as I dragged that wire off the post- acted like an arc welder - scared the crap out of me

[Dcsinclair22]

23 minutes ago, nelmo said:

I have a similar setup but I bought the main GBS loom, so I don't know where those 3 smaller wires go to exactly.

One thing I will warn you of, in case you haven't done this already; disconnect the battery before going anywhere near that thick wire. My first alternator died and I almost electrocuted myself trying to take that big wire off without disconnecting the battery. As it was, I literally burnt a groove in the old alternator body as I dragged that wire off the post- acted like an arc welder - scared the crap out of me

I'm hoping I don't need to take the big wire of but I'll definitely be sure to disconnect the battery first if I do so thanks for that. Just need to figure out the 3 other wires, then I'm pretty much ready for a little test drive, then I'm considering repainting the whole car but that's a thread for another day

[IanS]

this might help

[Dcsinclair22]

Thanks Ian, upon futher inspection the alternator wires are labelled (not including the big thick wire that goes to starter motor) so the 3 cables are b+ b+ and d+, all 3 originally ran to the positive on the starter motor then came of the positive and into the fire wall

[Sparepart]

I have done some investigation of the photos of the alternator that you have. I found an article about rebuilding an alternator that looks very much like yours, here is a photo from the article.

It looks like you have overkill on the charging cables, in that the big thick cable and the two large spade terminals are all delivering the output from the alternator. I'm gessing that at the starter motor there are two thick cables bolted to the same terminal, one is this one from the alternator and the other then runs to the battery. As the label on the photo here says, the smaller terminal is for the ignition warning light. The warning lamp lead serves two purposes. When the engine is not running, the alternator is not generating a voltage, the warning lamp is also connected to the battery, so a small current will flow from the battery through the lamp (illuminating it) and to the alternator and then the alternator earth. This small current is used by the alternator to start energizing the field coils, so that the alternator can start to generate voltage (and current). Without this small initial current through the alternator it will turn but not produce output. As soon as the output from the alternator reaches a voltage equal to the battery (12v) then the small current through the warning lamp ceases, and the lamp goes out. That's why the "ignition light" works the other way round from normal warning lamps, i.e. it goes off when all is ok. It is not necessary use a lamp to provide the small current, a resistor with the same value as the warning light resistance will do, it's just convenient to kill two birds with one stone. When some people replace all their waring lights with LEDs then if this warning light is replaced, the current flowing through the LED is too small to energise the field coils, and a small cuircuit to wire a resistance in parallel will be needed..........i'll stop now before I bore my own pants off.

[Dcsinclair22]

4 hours ago, Sparepart said:

I have done some investigation of the photos of the alternator that you have. I found an article about rebuilding an alternator that looks very much like yours, here is a photo from the article.

It looks like you have overkill on the charging cables, in that the big thick cable and the two large spade terminals are all delivering the output from the alternator. I'm gessing that at the starter motor there are two thick cables bolted to the same terminal, one is this one from the alternator and the other then runs to the battery. As the label on the photo here says, the smaller terminal is for the ignition warning light. The warning lamp lead serves two purposes. When the engine is not running, the alternator is not generating a voltage, the warning lamp is also connected to the battery, so a small current will flow from the battery through the lamp (illuminating it) and to the alternator and then the alternator earth. This small current is used by the alternator to start energizing the field coils, so that the alternator can start to generate voltage (and current). Without this small initial current through the alternator it will turn but not produce output. As soon as the output from the alternator reaches a voltage equal to the battery (12v) then the small current through the warning lamp ceases, and the lamp goes out. That's why the "ignition light" works the other way round from normal warning lamps, i.e. it goes off when all is ok. It is not necessary use a lamp to provide the small current, a resistor with the same value as the warning light resistance will do, it's just convenient to kill two birds with one stone. When some people replace all their waring lights with LEDs then if this warning light is replaced, the current flowing through the LED is too small to energise the field coils, and a small cuircuit to wire a resistance in parallel will be needed..........i'll stop now before I bore my own pants off.

Thank you very much for your detailed response, you are correct in the respect that the big lead from the alternator does run round to the starter, then up to the battery but (and here's where it gets a bit strange to me) the 3 other cables run round by the starter, then 1 thin cable runs through the fire wall (I assume this is the ignition warning light (never had one but must have run somewhere) but the other 2 cables 1 quite thick and one thin runs to the starter and connects to starter via a ring connector then come from the starter through the firewall too, where the thinner of the 2 went to a gauge and the thicker of the 2 splits about 10 different ways, so can I just cut the thicker wire down and run it to the positive on the new fuse box or can I do away with it completely?