Oil leaks.

[chaterlea25]

Hi Zander,
There is an oil scroll cut in the bush,
It has happened that inner and outer bushes have been fitted wrong way round leading to the scroll pumping oil into the dynamo case
If you are removing the inner timing case (before you do) check the rotating breather sleeve for looseness
Read the manual about fitting the cork washer to the breather sleeve,
If the sleeve is /was loose,  excess crankcase pressure will force oil out everywhere

HTH
John

[Zander]

Am sincerely grateful for all the constructive and helpful advice on here
The investigation will continue today.

[Zander]

Update2.  The scroll in the outer case bush is machined in such a way that  allows oil through instead of returning it to the crank case, so a new one is on the way.
I've also ordered the appropriate gaskets a set of tab washers and a full set of cork seals, so hopefully, I'll get it back on the road soon.

[Zander]

Update 3.  Not a good day in the workshop today.  A plus point was the arrival of the parts I ordered yesterday.  Excellent service from SRM.   The new idler bush is tighter than the old, so that's good.  The machining of the scroll is pretty much same as the old one, so oil can pass through into the dynamo drive chamber - not so good.  The oil hole in the new bush is half the size of that in the original one, so it begs the question whether to leave it as is, thereby reducing the flow of oil into the bush ( and into the dynamo chamber,) or to drill it out after installing it in the housing. To reduce the end float on the idler gear to about 0.010" ( too tight)?, I intend making a bronze bush.  I'm also tempted to fit an oil seal in the boss, but it will mean loosing 3mm of support for the end of the idler shaft. I think it would be ok, as there doesn't seem to be much load exerted by the dynamo chain.
Offering up the new gaskets, the timing case outer is fine but the inner one seems way out.  Are there different casings for certain engines I wonder.  I'll be asking SRM that question. On the dynamo front, I've read bikerbob's posts, and also everybody else's, tested the armature/ commutator, field coils, connections and brushes, and flashed it. Dynamo motors in the correct direction as on the casing, but still no charge

[duTch]

 I suggest send the bush back  for the correct one.

I have no felt/cork/other seal in my idler setup, and it doesn't appear to leak any (and I run my belt dry), and I've had the cover off for various reasons a few times, so get the right bush and go from there.

 As TTJohn noted;

Your quite correct in saying there should not be any oil in the dynamo compartment, so check your gasket that side also inspect the condition of the web inside the cover to make sure that it is sealing okay, the one that runs from the top down to just above the oil pump housing and make sure the web is complete......................TTJohn

,

 The interface web on my outer cover was only in contact with the inner one by about half, and being only about 3-4mm wide was not much contact.
To rectify this, I widened the webs by having the main casing (or maybe the cover-or both) professionally built up with weld on the oil pump side and dressed it to suit- this was also necessary because the belt drive pulley was interfering with the web on its side, and needed fettling down with the Dremel.
 

[Zander]

I think the bush is correct - it has the spiral grooves (scroll).  I'm also aware that this design must work, or there would be a proper "fix", so I accept that I'm probably looking to fix a problem that doesn't exist on the majority of A10's.  Regarding the idler gear end play, neither the crank case or inner cover bush heads show any sign of damage or excessive wear, but I'll fit a new gasket on the inner case and get an accurate measurement of end float, which I reckon will be over 1mm.  I'll also take into account the relationship of the idler and other gears in determining the size of spacer I'll make.
Needless to say, the gasket which was destroyed upon removal (inner case) is that which I have the problem with regarding the fit of the new one, so I'm reluctant to press ahead at the moment.  It will "sort of" fit, but it's not right.  Looks as though it's stretched about 4mm across the width.  I've emailed SRM to see if  my machine needs a different gasket.  It may, of course, be me just being a tart, but I want to get this job done properly, first time cos I want to ride it
The webs will come under scrutiny today - thanks for the pointers in that direction
 

[chaterlea25]

Hi Zander,
The early and late A models had different cases and gaskets
The gaskets I have had from SRM for late models have been OK
The scroll should be in the direction so as when the shaft rotates it will bring the oil back into the inner side..
As to fitting a shim?
I would not fit a shim between moving parts, If a shim is needed remove the bush from the case and fit a shim between the case and bush shoulder

John

[Zander]

Hi John
Thanks for info re the cases.  The one I got from SRM is too far out to use.  I emailed them but have yet to get a reply, so I've ordered another one from a different supplier hoping that I'll get a better fitting item.  Agree with your comment regarding the shim - I've placed it under the head of the bush.  While faffing about in the area of the timing chest, I noticed that the A/R bob weights were stuck wide open, so I've ordered new springs for that. The mechanism seems a bit stiff, so if the new springs don't sort it, it's off with the unit and something else to sort.  The dynamo continues to present a severe challenge.  I've not previously had a problem in this area and have always considered dynamo refurb to be a relatively simple job. Not this bugger, though
All good fun, ain't it?

[KiwiGF]

It sounds like it might be time for you to invest in a set of "wadd" punches and some gasket material, once you've got the technique of making your own gaskets, you will hardly ever buy another gasket (or fibre washer) 

[bikerbob]

Agree I make all my own Gaskets except for the head gasket whenever I have any casing off I always make up 2 gaskets one as a spare. You can get gasket material quite cheaply on ebay. As regards the fitting of the shim this was advised at the time by the the then BSA tech consultant, I take the point about  moving surfaces if they were dry but that shim is well lubricated and when fitted to my then A10 it caused no problems in the 16 years that I had it and when I spoke to the present owner he has had no problems so that shim has been in place now for 20 years. You have factory fitted shims next to moving surfaces in the rocker box and the gearbox but as long as they are lubricated will not cause a problem.

[Zander]

Yup, I made a few hole punches by turning  a chamfer on the end of a bolt and drilling the appropriate size hole in the end.  I had a stock of gasket material of various thicknesses but I've run out of a sheet big enough to make the one that I want.  SRM have replied saying that sometimes you have to trim them, but on the one I have, several of the holes are "hanging in the wind".  More gasket material on the way!
One of the reasons I put the shim under the head of the bush is that I don't have suitable sized materials in stock to make a washer type shim,  but was able to make one in two halves, which, as its encapsulated tightly between bush and inner cover, it won't be going anywhere.  I'd have been content to do it your way, bb. Thanks for the input, which is much appreciated.👍

[chaterlea25]

Hi Bob,
Rocker and gearbox shim washers are hardened so they work between moving parts
If you cut a shim from steel or brass shimming material they are not suitable for moving parts

John

[Zander]

Stewart from SRM emailed me this afternoon offering to send another gasket, which I consider to be excellent service.  👍

[ellis]

Nice Bloke Stuart. He is very helpful.

[bikerbob]

Chaterlea I see now where you are coming from and I agree with what you say but the shim I used all those years ago was at least 1mm thick possibly thicker which will account for it lasting so long and if I ever have to fit a similar shim in the future I will harden and temper it just to be on the safe side cheers Bob.