BSA B31: Strange oil leak from Timing case

[briancairns]

Hi,
I have a 1954 Plunger BSA B31.
I had to take timing case cover off to have work done on magneto. This ended up taking a few months, so cover was off bike for quite a while.
 When I put everything together and went for a test run, I noticed that after a few miles, oil was 'pulsing' out from the bottom right hand side of timing case. When engine stopped the oil leak pulsing stopped. There seemed to be a build-up of pressure in the timing case. Thus, the pulsing oil leak. Not just a slow drip.
I stripped it down again but noticed a few things and have a few queries. I have now taken cover off three times, but each test ride gives the same problem.
1.   Oil was returning to oil tank and circulating to head.
2.   I noticed that oil quill dropped out very easily and when put back in rotates very easily in its correct position, when I re-seated quill each time I ensured that hole in base of quill was aligned with hole in the place where you seat the quill but each time, I take it off, it has rotated, is this normal? Am I missing a circlip or seal for quill?
3.   Would the breather be blocked causing a build up of pressure, although I did shoot compressed air down the hole of the copper crimped tubing and it exhausted to the outside ok, when I reversed this procedure, air was prevented form going back up copper tube. Can I assume breather is working correctly? Should hole in copper breather tube be facing the cover casing (pointing away from bike, see photos)
4.   Would the rubber grommets/seals in the timing cover be damaged/dried out causing excessive oil to enter timing casing and thus a build-up of pressure?
5.   I checked oil level in primary casing ......all fine.
6.   I checked sump, no excessive oil but filter needed cleaning.
7.   Checked spring and ball bearing of the non-return...all fine.
8.   I have cleaned faces of timing case etc and used a new gasket each time I took cover off and used a smear of Wellseal to help seal the gasket.

Thanks in advance for any advice

[neil1964]

I presume that the gasket is new of good quality and was lightly greased.
Threads of screws and case all clean?  The oil pressure release valve cover washer is new and that the ball/spring are in the correct order and ball is seating. The quill will always get leak by and the rubbers on the cams need to be intact but unlikely a big issue. Oil is probably being blown out of the oil hole in the bottom of the cover bypassing the gasket.

[Ian C]

The quill should be a press fit into the timing cover i.e. shouldn't be loose!!

[briancairns]

I presume that the gasket is new of good quality and was lightly greased.
Threads of screws and case all clean?  The oil pressure release valve cover washer is new and that the ball/spring are in the correct order and ball is seating. The quill will always get leak by and the rubbers on the cams need to be intact but unlikely a big issue. Oil is probably being blown out of the oil hole in the bottom of the cover bypassing the gasket.

Hi yes, all new gaskets which I buy from Dragonfly (seem good quality) and I also use Well seal. I bought a new set of casing screws to see if it would help, oil pressure release valve cover washer is new. I will buy new rubbers for cams. Ball bearing is seated properly and both spring and ball bearing are new
What also concerns me is the oil quill when seated is very loose and seems to be turning when in situ therefore not lining up with the whole for the big end feed. I align hole from quill and casing cover, but when I take cover off again, they are always misaligned.
Also, it's not just a drip leak between the cover and gasket it is pumping out but stops when engine is stopped.
I have ordered new quill and Loctite 648 which is a retaining compound which will hopefully stop quill from rotating.
Thanks Brian

[briancairns]

The quill should be a press fit into the timing cover i.e. shouldn't be loose!!

Hi
I have ordered new quill and Loctite 648 which is a retaining compound which will hopefully stop quill from rotating.

Thanks

Brian

[cdsdorset2]

Have you checked there is not a build up of old sealant in the bottom of the casing screw holes. I use a woodscrew etc . It is supprising how much gets compacted in the bottom and reduces the clamping pressure.

[briancairns]

Have you checked there is not a build up of old sealant in the bottom of the casing screw holes. I use a woodscrew etc . It is supprising how much gets compacted in the bottom and reduces the clamping pressure.

Yes did that and picked everything out, the new casing screw set are slightly longer than casing screws on the cover, they fit perfectly and definitely get a better clamp or grip. I measured the length of screw holes and the new screws are not too long and fit ok.

Cheers

Brian

[V500]

Have you checked there is not a build up of old sealant in the bottom of the casing screw holes. I use a woodscrew etc . It is supprising how much gets compacted in the bottom and reduces the clamping pressure.

I use a drill bit rotated by hand. Amazing how much rubbish comes out.

[briancairns]

Have you checked there is not a build up of old sealant in the bottom of the casing screw holes. I use a woodscrew etc . It is supprising how much gets compacted in the bottom and reduces the clamping pressure.

I use a drill bit rotated by hand. Amazing how much rubbish comes out.

Just did what you advised, amazing! loads of rubbish came out.....but don't think thats the problem.
Cheers

Brian

[neil1964]

Although far from expert I've never seen a loose quill, and I guess from your description it is rotating and blocking the exit via quill to big end so all of the oil feed pressure is going to the oil way between timing cover and crankcase.
I've not used 648 (I use 243 blue as stud lock and 641 bearing fit) but I understand it is the green one that after 24hours cure is said to be very strong bond (assuming thorough cleaning prior) so correct alignment first time!!
Good luck and let us know how you get on.

[briancairns]

Although far from expert I've never seen a loose quill, and I guess from your description it is rotating and blocking the exit via quill to big end so all of the oil feed pressure is going to the oil way between timing cover and crankcase.
I've not used 648 (I use 243 blue as stud lock and 641 bearing fit) but I understand it is the green one that after 24hours cure is said to be very strong bond (assuming thorough cleaning prior) so correct alignment first time!!
Good luck and let us know how you get on.

Have ordered the bits and pieces so hopefully get job done this week and next, will let you know how it went.
Thanks for your advice
Brian

[Ian C]

Although far from expert I've never seen a loose quill, and I guess from your description it is rotating and blocking the exit via quill to big end so all of the oil feed pressure is going to the oil way between timing cover and crankcase.

There isn't oil pressure on the quill but there is some on the cams due to the seals between timing cover and cam shafts. Also the quill has an undercut as shown on Brians picture in the position of the oil feed hole, so can be fixed in any 360° postion and oil will still get to the big end. My comment was that if the quill is loose in the timing cover more oil would 'possibly' be escaping into the timing chest than designed.
In view of the quill being loose, I'd investigate why this has occurred. Is it a case of there not being enough concentric clearance between quill and crank?
To Brian, Have you tried placing the quill into the end of the crank and turning it?

[briancairns]

Although far from expert I've never seen a loose quill, and I guess from your description it is rotating and blocking the exit via quill to big end so all of the oil feed pressure is going to the oil way between timing cover and crankcase.

There isn't oil pressure on the quill but there is some on the cams due to the seals between timing cover and cam shafts. Also the quill has an undercut as shown on Brians picture in the position of the oil feed hole, so can be fixed in any 360° postion and oil will still get to the big end. My comment was that if the quill is loose in the timing cover more oil would 'possibly' be escaping into the timing chest than designed.
In view of the quill being loose, I'd investigate why this has occurred. Is it a case of there not being enough concentric clearance between quill and crank?
To Brian, Have you tried placing the quill into the end of the crank and turning it?

Hi Ian,

To Brian, Have you tried placing the quill into the end of the crank and turning it? 

Do you mean turn the kick start over?
The quill turns ok by hand when inserted.
cheers
Brian

[Ian C]

Thanks for confirming Brian. 

[neil1964]

There isn't oil pressure on the quill but there is some on the cams due to the seals between timing cover and cam shafts. Also the quill has an undercut as shown on Brians picture in the position of the oil feed hole, so can be fixed in any 360° postion and oil will still get to the big end. My comment was that if the quill is loose in the timing cover more oil would 'possibly' be escaping into the timing chest than designed.
In view of the quill being loose, I'd investigate why this has occurred. Is it a case of there not being enough concentric clearance between quill and crank?
To Brian, Have you tried placing the quill into the end of the crank and turning it?

How does oil get to the big end?
What happens if the quill is in too far and occludes the oil ways?
If the timing cover seals are too far in on a DBD you lose big end feed.