Hello,
I hope someone can enlightened me regarding magneto installation on my 1939 sq4. It seems like I’m missing a kind of oil seal holder, where the magneto axel comes through the engine casting. I found these two pictures in a workshop manual, clearly showing a kind of seal holder.
Regards
Henning
Your crankcase has been modified by a previous owner. I suspect the 4 holes were for screws to hold a plate onto the crankcase with a lip seal held in the plate. I would imagine that the plate and seal would be very thin. The original arrangement, which works quite well, has a sort of "top hat" arrangement inside the timing case and is a close fit over the shoulder of the magneto sprocket. That shoulder has a scroll cut into it which prevents the oil from exiting along the magneto shaft.
I will see if I can find a photo to assist in your understanding.
Paul Jameson
35 LG (project), 37 RH500, 52 ex ISDT KHA, 54 KH(A), 75 Healey 1000/4.
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist (but not Machine Registrar), Gauges and Clocks Spares Organiser.
Hi Paul,
Great news. I thought it was something like that, because my magneto sprocket has the oil scroll, but I thought there was a kind of sealing, rubber or felt. A photo and maybe some measurement would be great…
Your best bet would be to order a copy of drawing ET1001 from Roger Gwynn. This has all the information you need on it.
Paul Jameson
35 LG (project), 37 RH500, 52 ex ISDT KHA, 54 KH(A), 75 Healey 1000/4.
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist (but not Machine Registrar), Gauges and Clocks Spares Organiser.
Hi Henning.
When I first started up my 1945 SQ after restoration I had a problem with a major oil leak coming from the back of the timing case where the mag armature enters. As you show in your first picture taken from a workshop manual there is a boss that protrudes into the timing case that is supposed to allow the mag pinion scroll to draw the oil back in.
As you can see in the poor quality picture of my engine before the restoration it had been repaired at some time but still allowed oil out. Fellow member, Paul Wirdnam, suggested using an oil seal so I purchased a 26mm by 20mm by 5mm oil seal, we reamed out the boss to fit, machined off the scroll on the pinion to fit the 20mm hole and put it back together. Hey presto no more oil leak, well from that point anyway. Here is the link to Paul's listing of his restoration blog when he did the same to his 1939 SQ4.
1931 Ariel VB31, 1935 Triumph 5/3 project, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10 Super Flash, 1954 Ariel VH
