One for the mag experts.

[Rex]

I have two MO1L mags as used on the singles. Same direction of rotation, but one has the A/R cable at the front and the other at the rear and likewise with the HT pick-ups. Other than that they're identical, so would they be interchangeable?

[JulianS]

I suspect one is slack wire advance and the other tight wire advance.

The specification label numbers would identify the mags.

[Rex]

Well yeah, but that's not an important difference.
The label gives the direction of rotation, year of manufacture and mag type. It doesn't really help in this instance.

[Triton Thrasher]

They are likely to be interchangeable, if they physically fit.

As already said, rotating the cam ring against the rotation direction of the armature is advancing, so one magdyno is tight wire advance, one is slack wire advance.

[mikeb]

i believe they varied by which side the pickup  was on, by direction of rotation and by tight wire / slack wire. but otherwise the same. as Julian says the model number would help determine this and tell you what bikes they are from (find the lucas MO1 catalogue on the brightspark site). and as TT says they should work if they fit.

[ironhead]

Depending on what bikes they fit eg: BSA "M & B" models have the pickup facing the rear. Norton singles at the front.( not sure of other fitments, the ID tag will tell you, ( type number )if you read the Lucas fitment info ) It all has to do with clearance to frame, cylinder etc.

[JulianS]

Lucas magdyno fitment list uo to 1957.

The BSA singles used right fitted pickup.

[Rex]

That's an interesting chart Julian, and thanks for posting it.
Unfortunately 60+ years after mag production ceased we don't have the luxury of fitting the exact mag model for the bike concerned, so I'm hoping to fit a MO1L which came off an Enfield (and might have been incorrect for that model) to an M100 Panther.
Being a very "spacious" design behind the engine I'm hoping that the pick-up positioning won't cause any problems. Apparently the drive spindle height can alter between models but these appear identical, so here's hoping.

[groily]

All MO1s will have the same 45mm spindle height Rex, no problem there. Might have to sort out the base mounting depending on whether you need screws to bolt it on or dowels / pegs to locate in the platform with a strap over the whole shebang.
The direction of rotation is the most important thing, and completely off the top of my head I think  Oilfields and Panthers were both anti-clockwise drive. 90% of MO1s seem to be ACW, but pre-war Nortons went clockwise until the drive train was modded and rotation reversed.
The camplate for an anti-clock mag should have its depression - points closed period - about 6/7 o'clock to 9/10 o'clockish looking straight at it. Often, but not always, stamped 'L' for Left for anti-clock. Clockwise ones have their depression t'other side and may or may not have an R stamped on.
Tight or slack advance doesn't matter much as long as the cable run is OK. but the end housing could be swapped if necessary. Camplates might or might not be notched to work from either side.
The mag body could  be modded to take the HT pick-up on the other side if needed, and the open hole blanked off. Quite a few around like that in fact!
Swapping sides would affect spark polarity as you'd be using the other flip point of the armature, but otherwise nothing to worry about and no other mods needed.
So 99% for sure, no problem to do what you're doing  . . . fingers crossed!

[Rex]

Thanks Bill. Much appreciated.