My dad is half hr from Canterbury, on the coast between Dymchurch and New Romney, and is happy to give you a hand with his strobe if you want.

Thanks Russel, I might take you / your dad up on that.

I rebuilt the original carb today, which now seems to be running quite happily. The choke pull off thing was beyond repair though, so I just rotated the end cap to stop any potential air leak and removed the little arm.

I noticed the charge indicator had given up the ghost yesterday, I checked the voltage across the battery terminals with the engine running and it was nonsense, fluctuating to quickly to get any sort of reading.

I disconected the alternator and drove home, and had an investigate today. All the wiring looks correct, the battery was at about 12.34V with the ignition off. At a (low) idle, it was reading 14.3V (not fluctuating this time), and when reved it dropped to about 14.24V - but the charge indicator on the dashboard still wasn't reading anything.

Not overcharging at least, but I don't trust it not knowing what's going on. Would the voltage regulator be the first port of call, and is there any way to test it other than replacing it? Is the indicator on the dashboard simply a voltmeter reading the battery voltage?

Thanks!

Copy & paste from that other forum...

George,
have you had a look at the alternator brushes?
If they're well worn down, you can have the situation where they will make good contact with the slip rings at tickover or just above, but fail to do so at higher rpm.

The instrument in the panel is a voltmeter, but of the 'hot wire' type, so it's slow to react in comparison with a moving coil type.
Also, if the battery is low on charge, it can take a few minutes after startup for the needle to move across the scale...

Ken

p.s. This might come in handy since you've ditched the choke pull-off gizmo.
http://www.flickr.com/photos/3013285...9456q4-bmCsND/
http://www.flickr.com/photos/3013285...-9N1kYa-aEorCC

Well, huge thanks to Russ's dad for the use of his stroboscope, coffee and biscuits! The timing was definitely out, so I'm glad I did that, can't get any signs of pinking out of it now.

However, there is still something fishy going on with the charging. The voltmeter on the dash sprung back to life, and it the charge regulator seemingly fixed itself. Being poor I decided not to question it in case it needed expensive new parts!

On the way back from uni today though, I noticed the indicators had given up flashing. Upon investigation, the flasher was fine, but the battery voltage was fluctuating wildly again, presumably upsetting the circuitry in the replacement flasher unit.

Here's a crap video to show what I mean about the voltage fluctuation:

http://s895.photobucket.com/user/GasMar ... e.mp4.html

That's connected directly to the battery terminals, and every now and again you see it flicker to 150V or something nonsensical like that. The amount of flickering to nonsense voltages goes down a bit with increased engine rpm.

There is a good ground at the regulator, and I tried another regulator with similar results, which led me to the alternator. The brushes don't seem too worn, and they still get pressed in against their spring by a reasonable amount when fitted.

Not quite sure where to go from here, should I splash out on a replacement regulator (I just tested it with a L78S12CV regulator chip I had lying around, mostly because it had '2CV' in the name...). Or is it more likely to be a fault with the alternator, and is there any way of deducing where the fault lies?

George,
to avoid the risk of repetition.
http://www.ebay.co.uk/itm/VINTAGE-VOLTM ... 2a333ca702



Might have a go at this one myself if you can't borrow/liberate one from the labs...

ken

What are the brushes like in the alternator?

They're a lot more suspicious about borrowing from the labs now, back at sixth form they would let me borrow cloud chambers and oscilloscopes and so on, here even a voltmeter is forbidden. Liberation is an option, but I'd rather wait until they've submitted the marks for my lab report just in case! The reason for my puzzlement was that I had used this voltmeter on dad's 2CV without any problems, and on mine for the first month. Anyway, improvising with what I had to hand I made a potential divider and calculated the voltage using an arduino, displaying it to my laptop screen through the serial monitor. Whilst still digital, I didn't notice any of the fluctuations I was getting before, so maybe it is just my voltmeter having an off day. The indicators are working again now anyway, with the addition of a proper bimetallic flasher, so I will keep an eye on it and see how it behaves. Aside from this, I haven't had any problems, started straight away every time, and I've been getting around 50mpg which I think is pretty good for a van.

Thanks for your help

I get the same effect sometimes using my cheapy multimeter in the engine bay. I'm not sure whether it's down to grubby contacts in the VR, causing the voltage to oscillate, or down to poor shielding in the meter and its leads, and HT interference. Checking the voltage inside the car, at the ignition switch, for example, seems to be fine, so I suspect it's the latter. In that case you might be able to improve things with judicious use of tin foil, I suppose.

Your way sounds more fun though!

@arduino
Like!

George are you planning to make a replacement reg using the L78S12CV.
Interested if you do?
Cheers