Lucas Magdyno Numbering

[Pete.Silson]

Does anybody know what a Lucas KN1E magdyno is? Externally it appears to be an MN1E but I can't seem to find it listed in any references. I assume the 3 37 means March 1937.

Pete

[paul.jameson]

Using pure guesswork, has the KN1E got a manual advance retard or not? I suspect it may be an automatic or fixed advance.

Assuming In am wrong - which is highly likely - give Tony Cooper a ring and ask him.

[pete.collings]

My 1958 Lucas catalogue gives KN as a 45mm spindle height, and 1E as for use on four cylinder machines, does this match up with the magneto itself, can't make out what it is from the photo, a pic of the entire mag would be helpful.
Be aware the details plate is easily exchanged, so may not be original.

[Pete.Silson]

Paul,

It does have a manual advance/retard and, on further seraching the Lucas parts catalogue, I have found the seriel number (463602) listed as an MN1E used on 1936 and early 1937 4G's. I guess it must be a typographical error on the plate.

Pete

[nevhunter]

The Scotts ran a similar magneto. Both run at engine speed. Perhaps the reason for the (E). The four needs a distributor. Nev

[leon.mitchell]

The "337" part of the stamping is, I think, the date stamp for March 1937. Many Lucas products used this date format - even some of the acetylene bicycle lamps from the early 1900s.

Leon

[paul.jameson]

My theory for the KN1E as opposed to MN1E being fixed as opposed to cable advance retard was based on my idea that the K2F has fixed advance retard and uses the automatic system in the gearwheel drive to advance and retard. I did say that I was likely to be wrong and so it has proved to be.

So let's try an alternative argument and work on the idea that the K refers to the magneto HT pickup being held on by a spring clip rather than by the 2 screws used in the M version.

Can you take your HT pickup off and see if there are a) the holes for the 2 screws (which appear to be missing from the photos you have posted) and b) whether there are locating holes in the magneto body for an HT pickup held in place by the spring clip visible on your photo?

Again, I may well be wrong, but I am used to that after 40 odd years of Ariel ownership.

Either way, I am pretty sure that your KN1E magneto has the thinner fibre gear driving the dynamo and distributor. You can tell the difference by looking at the end plate. The wider gear version is a flat plate while the narrower one has a stepped end plate. When this fibre gear strips you lose drive to the distributor so it becomes a recovery home job,as a rule. Presumably this is why Lucas moved to the wider gear fairly soon after the introduction of the magneto mounted distributor for the Square Four for the 1936 season. Without going out and measuring the gears, I think the wider gear is about a third wider than the narrow one so has a much longer life. The wider gear seems to be standard post war but I don't know if they appeared pre war.

[Pete.Silson]

Hi Paul

The HT pick-off has two threaded holes with locating pegs and a spring clip rather than screws. I have three examples of MN1E magdynos all of which have the same arrangement. Does your 4G magdyno have two screws? Most examples of MN1x, MN2x I have come across seem to use two screws but I have seen examples with both. Presumably the spring clip lets you take out the HT brush without dismantling half the bike to get access to the screws. The only case I can see where the spring arrangement wouldn't really work is where the HT leads comes out at 90deg as with an MN2 used on a horizontally opposed twins like a Douglas.

The KN1E end plate appears identical to both my other (post-war) MN1E's and it looks to me like it has the wider gear-set although this could be an addition from a later rebuild.

The "KN" prefix is listed in the Lucas Spares Magneto section as "45mm spindle height" (as in the KN1). Maybe Lucas used KN1E for this early incarnation of an MN1E (which has 45mm spindle height) but later changed it MN1E to be consistent with other magdynos. The "1E" is listed as "For use on four cylinder machines" which is consistent.

Sorry to shoot down another theory but keep them coming. I am glad there is someone else out there intrigued by the details.

All the best Pete

[leon.mitchell]

The "KN" prefix is listed in the Lucas Spares Magneto section as "45mm spindle height" (as in the KN1). Maybe Lucas used KN1E for this early incarnation of an MN1E (which has 45mm spindle height)

Hi Pete,

"K" usually refers to 45mm spindle height, and "M" to 35mm. Are you sure that an MN1E is not a 35mm instrument?

[Edit: True for magnetos, but not for magdynos it seems! Draganfly has some ideas https://www.draganfly.co.uk/index.php/a ... fh-1948-58 :

1936-49 Singles MO1 MO = Magdyno with face cam, 1 cylinder with short 40 Watt dynamo
1950-58 Singles MOIL MO = Magdyno with face cam, 1 cylinder with long 60 Watt dynamo
1955-57 HS MK I KNR1 K = lightweight unit, N=45mm spindle height, Racing, 1 cylinder
1948-57 KH/FH K2F K = lightweight unit, 2 cylinder, Flange mounted,
1936 4F MSL1S MSL = Magdyno with 3rd brush dynamo
1937-48 4G MN1E MN = Magdyno with ring cam, 1E = 4 cylinder machines
1949-58 MK I/II DKX4A = Distributor, KX, 4 cylinder, Automatic advance]

Cheers

Leon

[paul.jameson]

Hello Pete,

I have 2 screws holding my HT pickup on but no spring clip - although there is a screw filling a hole where a spring clip may have been. Remember that I didn't have a magneto at all when I bought my 1936 4G so I was glad to obtain one which would fit the bike (and which has the wider fibre gear, although that is probably wrong, but very, very few people could spot that).

The narrower fibre gear is 3/8" wide and the wider one 1/2" wide. What are yours?

I can see this thread ending up in me riding the 4G down to you to compare notes !