This has never been my strongest side. I can't understand how this works.

Battery dead this morning including all indicators. Replace battery, started no worries, checked the alternator and regulator. Here come the interesting point. Reading fluctuated from 14.2 to 18 volts which lead me to replace the regulator. Same result with a new regulator, moved on to brushes but OK. To eliminate the alternator, I fitted a new but fluctuation continued. Moved on to the 3 wires on feeding the regulator.
1 coming from the alternator (field) OK
2 coming from earth (middle spade) OK
3 coming from + suddenly had earth, no good or what?

Didn't understand where the earth came from. Began stripping the loom looking for a faulty instrument suppling the earth. No luck.
Ended on the coil pulling one wire off (- or + same result) and bingo the earth dissapeared on the plug feeding the regulator.
Became suspicious, connected both wires on the coil and sure enough, when turning the engine with the pionts closed I had earth of the regulator plug. When points opened back to ''normal''
Bugger I've never seen this before or maybe I've forgotten. Can someone please explain as I have no bloody idea.
I guess this explains the flucuation when engine is running, points breaking the circuit.

Hello 2CViking,

First of all connect the terminals of the multimeter to the correct slots, that is black to com and red to Ω/V .
If you measure current up to 1-10A then red to 10A slot.

It's normal to have voltage droping when the contacts close as the coil has low ohming resistance.

OK but I still get a reading when the points are closed.



Also discovered that I get similar reading when the oil pressure circiut is connected...???

The coil should have in the primary 3-4ohm so this is normal.
The capacitor maybe is short circuiting.
Is the new battery really good?
Disconnect everything except the bettery and see.

Next step will be in a methodic approach.

The battery is not connected, same for alternator.
The voltage meter is set on sound telling when I have a curcuit. I get the sound when points are closed, also when oil pressure circuit is connected. As soon as I disconnect points the sound goes or when turning the engine so the points opens. When pulling the wire off the oil pressure circuit the sound goes.
When battery is connected and alternator running, I get 14 - 18 volts regardless of the regulator. I think that the + wire on the regulator turn negative when the points are closed

Viking,
is the ignition switch in the 'on' position?
The voltage regulator ( as well as the wiper, oil pressure, choke warning, etc, etc.) should not be linked to the ignition circuit unless the ignition is switched on...

ken

I followed the wires back to the dash and disconnected, wiper motor, fuel gauge, hazard switch, warning lamps + the 2 yellow on the ignition switch. I noticed when disconnecting oil pressure warning lamp that the sound disappeared, however the sound continue until the points open.
I can not for the life of me understand how there can be a curcuit when everything is disconnected.

Viking,
that's the whole point of them being on the same circuit, so that they all go live when the ignition is switched on.
Unless you cut the individual wires leading from the fusebox, you will find that there's a path to earth via the oil pressure switch, points ( intermittently), fuel gauge and so on.

The only checks you need to do on the wire which is feeding 12 volts to the voltage regulator is that there's no voltage with the ignition 'off' and 12 volts with the ignition switched 'on'.

Problems with too much voltage being delivered by the alternator are most often caused by a poor earth for the regulator.
On a couple of cars, I've had to run a separate earth wire from the 3 way plug onto the body or onto the gearbox.

ken

The coil also?

I was thinking about that too. Just a bit concerned, I have a small spark when I connect the negative to the battery.