Seems to be plenty of info here

Rob

GC, beat me to it !!

Hi

If you remove the armature from a BTH magneto it will definitely lose it's magnetism unless you use a keeper, Lucas mags have a different magnetic material that holds it's magnetism.

Best source online for magneto information is as stated above the Brightspark magneto's site which has loads of information and how-to's on magneto repair and they also do remagnetising. I've used them in the past for parts and rewinds and there service is very good.

Dave

Edited By Dave Wootton on 03/12/2020 15:56:10

Reminds me of a story my father told about the TA(or whatever it was in the 1930's). At the time he worked as a mechanic for the firm that supplied and maintained the trucks. He was sent on an exercise in NWales with a big group.

The sargent in charge lined up the squaddies and after asking who could drive, added enough extra to give one per vehicle on the you, you and you principle. Father was then asked to give basic instructions. And off we go.

Some time later ascending a steep pass one truck was smoking very, very badly, think smokescreen! At the next stop they investigated. Oil was overflowing out of the engine. The sump was full to the pistons. When asked the squaddie said " You said to add oil if the oil pressure dropped. Every time I switched off the engine at rest stops the oil pressure dropped to zero – so I did as I was told".

Nice rig Maurice!

It looks like a re-cycled washing machine motor, do you have a speed control on it? For testing magnetos or other ignition systems it is also very handy to have a 'rotating spark gap', this is a asynchronous electric motor driving a spark gap, adjustable to give a range between 0.125" and 0.5" (the bigger gap is useful for high energy systems such as CD ignition ). If a misfire occurs due to breakdown of the system the spark gap immediately allows you to recognise the 'missing' spark as the sparks form a pattern such as a 3 point, 4 point, 5 point star etc as system speed increases.

We used these 'RSG's' as a way of setting the soft and hard ignition cut on the Lucas Race Ignition boxes, we set them up 60 rpm 'soft' and 20rpm 'hard' below the Monk limiter of the F3000 cars as the Monk denied for 2 secs and was a huge disadvantage if a driver triggered the Monk system. Very useful bit of kit which we recycled out of the Magneto service department.