1961 model 16 oiling problems

compo · Post by **compo** » Sat Jul 30, 2011 10:39 am

Engine oil is transferring into the promary drive chaincase at an alarming rate.

I believe that it can only be the crankcase oilseal.

has anyone tackled this problem?
If so any tips and are specilal pullers/extractors required for removal of drive sprocket or clutch assembly?

can the job be completed with the engine in frame?

Could oil accumulated in the sump due to excessive wet sumping have caused the seal to blow, if indeed that is the problem?

Any advice would be greatly appreaceated.Text

SPRIDDLER · Post by **SPRIDDLER** » Sat Jul 30, 2011 11:38 am

Welcome.
There isn't an oil seal in the c/case at the main bearings. See engine drawing in Workshop Manual.
The excessive oil in the primary case could be due to high c/case pressure as a result of worn cylinder/rings allowing gases to escape past the piston into the c/case. Or 'Wet sumping' (which see by using those keywords and using the 'Search Forums' facility).
Does it run o.k. and without smoke or oiling of the sparkling plug?
This workshop manual will answer many of your questions. This one's for the Matchless which is the same as AJS:
http://archives.jampot.dk/Book/Workshop ... 7-1964.pdf
Members of the Sussex section will be very willing and able to help if you come along to our club night. See Section Forums.

BTW- Read the two 'Stickies' at the head of this Forum section which will confirm, A) how to do Forum searches and B) you'll note that your question should be in the 'Help' section...
Quote:
"This area should not be used to ask questions or provide the answers - that should all be in the Help forum".
No doubt our Moderator will move it there in due course.Edited by - SPRIDDLER on 30 Jul 2011 10:42:27 AM

compo · Post by **compo** » Sat Jul 30, 2011 8:46 pm

Thanks for the info.
I drained thye sump and drew best part of a pint and a bit out.
Drained the primary chaincase. refiiled with oil & roadtested.

No problem.

Wetsumping seems to be the problem.
Thanks once again.
Compo

bigwol · Post by **bigwol** » Sun Jul 31, 2011 3:16 am

Surprised you have this issue with a single, is usually the twins wet sump and fill the chain case!

rex.webb · Post by **rex.webb** » Sun Jul 31, 2011 5:02 pm

All the singles i have owned have "WET SUMPED" if left for to long.
MUST get them out and DRAIN THE OIL !!!!!!!!!!!!
RIDE with CARE and LIVE LONG to ENJOY your BIKES.

SPRIDDLER · Post by **SPRIDDLER** » Sun Jul 31, 2011 8:42 pm

After Marigold had stood, bent in t' shed for 10 months we drained 2 pts out ...

Jez H · Post by **Jez H** » Mon Aug 01, 2011 11:33 am

Does the oil build up in the chain case while the engine is running?

SPRIDDLER · Post by **SPRIDDLER** » Mon Aug 01, 2011 12:23 pm

Yes.
If due to high crankcase pressure (running with worn bore or rings):
Some oil or oily mist will pass as designed through the crankcase breather (an outlet at the main bearing swelling in the c/case casting behind the inner chaincase) and out onto the lawn (via a small dia short copper pipe, if fitted). See engine drawing.
Some oil mist/oil will also pass from the crankcase through the two main bearings and into the chaincase.

Build-up of oil in the chaincase can also be due to wet sumping:
If the bike is left unused for a while (days, weeks or perhaps months) oil will drain slowly from the tank past the oil pump and collect in the bottom of the crankcase. When th'engine is started and before the oil pump has managed to return this oil to the tank some will be forced out of the breather, some via the main bearings into the chaincase and some may also be forced up the cylinder (by crankcase pressure generated by the descending piston) into the combustion chamber resulting in a fouled/oily plug and substantial smoke (burnt oil) from the zorst.

Marigold stood for 11 months on the centre stand after my accident. When we put her onto the side stand oil began to run out of the crankcase breather. We drained about 2 pts from the 'sump'.

Jez H · Post by **Jez H** » Mon Aug 01, 2011 12:35 pm

ahh yes. My question about it building up while the engine was running was related to the original post.

If it is building up enough to go over in large amounts into the chain case while the engine is running then it sound to me like a sluggish oil return rather than normal wet sumping while stood. Mine had this problem and then eventually blocked completely and also the relief valve you mention lets go quite spectaculary dumping extremaqely large amounts of oil onto the road.
18 months later you can still see the big stain by the side of the road where it did it. C

SPRIDDLER · Post by **SPRIDDLER** » Mon Aug 01, 2011 1:13 pm

Hmm. "Eventually blocked completely" eh? Now he tells us!!
Yes, if the pump isn't returning the oil fast enough it will build up in the crankcase when th'engine is running.
Can you see oil returning into the oil tank, initially at start-up in a continuous stream, then in bubbly spits and spurts, (which is normal)?
Poor oil scavenging/return can be due to a number of things:
Blockage - e.g excessive gasket sealant logded in crankcase oilway. Collapsed or squashed/pinched return pipe.
Air leak at the front or rear pump cover plates (the ones secured with BA screws).
Front cover plate gasket incorrectly fitted.
Plunger guide pin incorrectly fitted or worn at the end which locates in the plunger eccentric annular groove.
Damaged plunger splines/worn plunger....(Unlikely)
The breather is a free-floating thin steel disc flap valve sort of arrangement. If, as you say, "it lets go spectacularly" it's possible that this could become jammed shut or stuck by crud or gunge (technical terms) until the pressure rises enought to free it, although I've never come across that. Annoyingly the inner chaincase has to come off to access it properly.
I suppose the breather outlet pipe, downstream of the flap valve, could have become blocked...

(Bored, looking out glumly at the fine day with time on my hands, having been immobilised indoors for the past week after further ops to remove five 3 1/2" self-tappers from hip, knee etc.
)Edited by - SPRIDDLER on 01 Aug 2011 5:29:57 PM