Hi all...my 1941 WM20 has sprung an oil leak between the engine casing and the the magdyno at the magdyno pinion oil seal. The fault is not the oil seal as it is new. The problem maybe with the casing around the oil seal. It has been worn away on one side. I am reluctant to put sealants in the area as I think they will breakdown and block oil holes within the engine. Perhaps another reason for the oil leak is that I may have the oil seal in the wrong way, I have the flat side of the seal flush with the casing, but the bevelled centre of the seal matches the magdyno pinion drive cog shaft, suggesting it needs to be turned around. Has anyone had this problem, and did you find an answer?

Regards,

Bryce

The lip of the oil seal, ie the bit with the spring round it, should be facing the way the oil comes from. You could try putting some wellseal round it. Very sticky stuff and won't break down. Coat both surfaces and allow to set for about 15 minutes before assembling. Always worth having a tube in the workshop anyway.

http://www.wellseal.co.uk/

Ron

email (option): ronpier@talk21.com

thanks Ron i will give it ago

Wear in the seal housing is a fairly common problem caused by the engine being run with the magdynamo straps not fully tightened...

The REME had a repair for this which they carried out when the engine was overhauled. They bored the crankcase until the seal housing was completely removed and then fitted a stepped brass 'top hat' ring which incorporated a new seal housing.

This was retained in the crankcase by 3 countersunk screws...

I have found there is frequently enough material in the seal mounting boss itself to remachine it to a concentric hole without breaking through the side of the boss...

I then turn up a thin aluminium ring which is a 'snug' sliding fit in the remachined boss and has the correct inside diameter for the seal...This is retained in place using bearing fit Loctite....

The initial problem with any form of repair is accurately establishing the original centre of the hole to ensure that when machined it is concentric to the mag armature...

I have made a 'clocking' jig for this job....

Unfortunately these more permanent and 'correct' repairs can only be carried out when the engine is stripped...

To avoid the problem it is worth developing the habit of checking the tightness of the mag straps every so often as part of normal maintenance, or if already damaged, to prevent it getting any worse!...Ian

email (option): ian@wright52.plus.com

Thanks Ian...as usual very insightful

Also check the condition of the crankcase mag base, shims and mag lower face as these often erode due to the magdyno dancing about. After tighening everything up check the mag pinion/ idler mesh.
Richard