Morris Minor Owners Club

Looks very nice

Thanks, Wish it worked as good as it looks.

At least it's nice to work on. Everything comes apart as it should and not caked with crud.

is this of any use
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Smart looking engine bay - but can't see - is it running -ve earth or +ve earth ?

Thanks for the info.

Car is +ve earth.

Well - the test will be to see if the dynamo 'motors'!

Morning all (well almost)

First test done and the dynamo 'Motors'. How fast should it motor? I'm guessing mine is turning about the same speed as it would when connected at idle.

Starting to follow Mogwai's charts now

Following Mogwai's chart but I don't have a control box, just a dynamo and a regulator.

I forgot to mention, when measuring the voltage across the back of the dynamo, it kept jumping to 10-13v every so oftern. Difficult to tell with a digital gauge.

Control Box = Regulator

Thanks.

I went back to basics. Voltage from the small terminal on the dynamo = 0.2-0.3v. Voltage to the large terminal 1.2-1.5v.

I would expect 12-14v and hence I'm going to change the dynamo. It's not expensive but would give peace of mind.

If the dynamo 'motors' - it's fine! Don't change it - look to the control box and the wiring. Your motoring test will also have polarised the dynamo correctly - if it was wrong before - so it all may work correctly now anyway!

The small terminal is the field connection and is fed from the regulator to control the output level of the dynamo therefore if the voltage on this terminal is 0 or near to it the voltage on the large output terminal is also zero. As your dynamo motors it is in good order and the fault lies in the regulator or the wiring to it

Another quick test is to run a temporary connection from the battery feed to the small terminal whilst the engine is running, the dynamo will then charge at full output so proving it works (disconnect the small terminal from the dynamo to the regulator before doing this).

Look at this diagram below. The right hand contact should close when the engine is reved and stay closed for a while after going back to idle, this is the cutout contact and connects the field to the battery. Remove the top of your regulator rev the engine and gently push the cut out contact to make the circuit as occasionaly they can stick and once prodded into life they work fine. do not hold it down if it wants to pop straight back up.<br><br>

Ok, it's all starting to make sence now.
So my problem lies with the regulator not telling the dynamo to produce power. Correct?
The photo of the engine bay was from last year and I have just changed the regulator because originally we thought that was the fault. I'll check my wiring from today back against the photo and see if I've connected something up wrong.

2 weeks ago when she broke down, it ran ok on ther dynamo but didn't charge the battery and hence changing the regulator.

Duncan

Yes good idea check the continuity of the wiring ( resistance or bleep, if it has it, check on your meter) from the dynamo to the regulator (disconect both ends before testing as you will get a paralel circuit giving false readings otherwise. With luck it will be something simple like 2 transposed wires for instance. Good luck with it

To clarify A & A1 are connected together and will be at 12 volts as it connects to the battery. D goes to the big terminal of the dynamo F goes to the little terminal of the dynamo and E goes to earth

Well done Nigel - Problem solved.

I used a fly lead direct from the battery to the small terminal and the large terminal gave 11.5v upto 13.5v when reved.

I then took the cover off the new regulator and the little arm on the right was not moving. After a little prod, she clicked down and the charge light went out.
When returning to idle, it didn't click back up like you said, but did after I turned the ignition off. Is this ok?

Yes - although I would have expected it to open at idle speed - unless the idle is quite fast ? I am wary of advising folks to prod that contact down - because if it sticks down - it can run a very heavy reverse current back into the dynamo - possibly causing a fire and certainly flattening the battery quick time ! So - just make SURE the contact opens when you switch off.

Hi bmc
I have a problem with my regulator in that the red light stays on until I remove regulator cover to flick contact to make light go out ,but when I start car again it happens again can any lubrication be done to the mechanism and if so what can I use
Regards Ian

No - not lubrication! Ypu may be able to make an adjustment to bring it in earlier - or I seem to remember bending the retun stop down slightly to hold the top nearer to the core. But the worry is - if it 'sticks in' - there could be trouble ahead. Try by all means - but I do suggest looking out for another control box - although i wouldn't go as far as buying a NEW one. Alternators can be picked up cheaply - i'm sure regulars on here will know I refuse to pay more than £1 for one ! And -although some disagree - I find them very reliable. So - if the dynamo continues to be troublesome - rather than spend a fortune on it - look out for an alternator!

hi bmc
problem is my car is sidevalve and an alternator will look out of place the regulator was replaced in the past as it is not the screw terminal type and looks clean inside I was thinking of one of using one of the switch cleaning sprays
Regards Ian

Ahh - yes - I can see why you want to stick with dynamo! No harm in the cleaning spray. Is it a normal regulator -as depicted above ^^^ in nigel's helpful diagram ? If so - the adjust screw is shown (item 2) and the stop arm (item 4) - you could try the tiniest closing in of the stop arm!