Mk 3 wet sumping valve - where is it?

They often stick in the housing, especially if the oil is a bit old and sticky - DON'T try to fit one without verifying that the original is not present.

Try measuring the depth of the smaller gallery next to the crank feed. It should read about 0.8" deep.

If yours is there and stuck, a tap on a wooden block might free it, otherwise turn it upside down and lightly play a blow torch over the bulge on the case. As the oil thins, the spring normally pushes the plunger out. If it's really stuck then you might have to resort to drilling it and forcing a self-tapper in to aid extraction but this will mean replacing the plunger.

If the re-used crush washers you refer to are the exhaust pipe to head seals, I would refit the "crushed" ones. New ones will need continuous retightening until they too are fully crushed. Inbetween times your pipes will be losening off and this is the thing to aviod when running a Commando as it damages the head threads.

hi Chris

Am rebuilding my mk2a 850 an fittednew oil tank banjo alloy washers an the one between the bolt head and the banjo leak no mater how much force was applied (lots more than you should have to)

Copper is mush better for sealing washers but on the ACCESS NORTON Website (google it they have many helpfull threads) there are people who say copper washers also leak on their bikes.

i fitted two Dowty type washers to my tank an that stopped it leaking without have to pull the thing over tightening the bolt! If you have not seen a Dowty seal its a metal washer with a rubber type seal in the bore that seals the faces as the washer is trapped between the bolt and banjo fitting. They are use in high pressure hydraulic systems so will have no problem with oil system on a Norton.

I can not tell you the size or make of the ones I fitted as I just went to a local hydraulic fitting company showed them the parts the man gave me two an said I could have them as they are only pence and not worth the paper work.

Have fun Karl

Looks like Norton anti-wet sumpingdevice wasomitted by whoever last rebuilt engine. As already pointed out , check first it's not stuck inside housing with spring compressed which is a common problem (and was on mine when I stripped engine). I'd strongly recommend just forgetting this not very effective Norton designed anti-draindevice and fit a Mick Hemmings valve which is a simple job fitting in the outgoing oil pipe from the oil tank and which really does work properly.

If I were to delete the valve and continue using the Mk3 timing cover, I think that I'd want to block the bleed drilling from the rear of the plunger. Otherwise, a certain amount of the oil pump's output will be sprayed inside the timing cover rather than directed to the big ends. It may not be significant but I wouldn't want to be the one to find out.

I reckon that if you ensure the housing has no burrs and polish the plunger so it's an easy sliding fit, you shouldn't have a problem and it will work more often than not.

The good thing with this system is that the valve is pushed open by pressure, rather than relying on suction drawing a valve off its seat.

I've never done it without the tool and most camshafts have a fairly sharp edge. The 'tool' doesn't have to screw in (although that's easiest). It would probably be possible to fashion something out of a piece of wooden dowel. It just needs to gently open the seal as the case is pressed home.

Hi Chris

you can fashion a thin plastic sleeve from an old tizer bottle, just cut yourself a section of the bottle 2 by 3 inches, roll the plastic so you have a tube lets say half inch diameter by 3 inches long ,poke this through the new camshaft oil seal which is already fitted to the timing cover , you can use the plastic tube to locate over the sharp camshaft edge and protect the seal from snagging when you re-fit the cover,once the covers home you simply slide the plastic out.

I've also used this method ,but on a larger scale ie thicker plastic shimming to set the rotor/alternator clearance

steve

my primary did the same thing no leaks after filling or when standing for a week or more. But after running the engine a short time a few drops but still not when stood. Then off for the MOT its first time on the road for 30 years an my first time on a right foot gear shift ( boy that eas fun) an oil dropped steady off it but after cleaning no drips when stood.

I check oil tank level that looked same as before then checked primary it had just enough oil to be seen when you remove the level screw. As no part of my garage drive or street is level (sheffeil is all hills and slopes) i my have over filled it an i hvae read that even when filled to the level that is to much an will leak.

i will leave it alone an see if it stops after a short while if you are sure it is not a major leak an would be ok to leave i would do the same if i was you just for a short time to see if as the level drops the leak stops by its self. You can remove the plug that gives a veiw of the primary chain to see if it still has plenty of oil on it for time to time.

Karl

I'd say that the most likely source, assuming the chaincase face is sealing properly is from the alternator lead grommet, especially if the lead has been positioned so that any oil splashing onto it can run downhill. The grommets do harden.

Gearchange crossover shaft is another possibility on the Mk3 (but I've never had that one).