Forum

[Norm]

The feed pump can only deliver half what the scavenge pump can/could remove, if you have a excess oil in the sump it is because the scavenge pump is unable to remove the oil due to some restriction simple as that. Smoking out the breather means your bores are probably glazed and the rings not bedded in

[Tim NZ]

You have nothing to worry about filling the primary with oil. There is no possibility for oil to pass through the crank breather unless the sump is FLOODED!
The Connie motor has a raised oil level in the ex cam tunnel to prevent excessive wear due to the hotter oil from off the exhaust side. It is then possible for the oil to pass out the 'window' into the sump proper, thus not getting to the timing chest, and over loading the sump...
But you have fitted a Large bore return pump, which was created to over-come that very situation.


Blocked oil ways: I have encountered casting flash obstructing the sump pick up: 7/8 of SFA able to get up to the pump...


I have found the head of a broken drill bit wedged into oil drillings where someone had attempted to open them up...


I have encountered LARGE lumps of cast alloy in galleries that could not have passed in or out of the drillings! Dislodged internally from cross drilling oil ways...


You had the problem previously. and have replaced EVERYTHING, except the timing cover...


Your pistons will be OK, but your rings may be damaged?


For the rings to function correctly, there MUST be negative crankcase pressure, or the rings wont seal correctly.


You MUST have a non return of some sort attached to the breather; the Duck-bill hose is ideal, but typically its location is not.

Check your rings and renew as need be


Reinstate the crankshaft breather.


Confirm ALL drillings, every single one including the oil pump discs, the galleries and gasket matches on the timing cover, if need be fit one of your other bikes T-covers to substitute.

[Tim NZ]

6 bolt oil pump covers???!!!


Big sigh.


I think you you have the wrong timing cover! All the six oil pump covers I have seen have been designed to have ALL the return oil drain into the sump, and the OPR vents back to the oil tank. Both sides of the return suck from the sump and none from the timing chest! The oil way drillings in your pre 1960 cases are not the same!




You definitely need to confirm ALL drillings and that they match

[Bullet Whisperer]

There was a big twin [Airflow] brought here a couple of years back, which the owner had paid a lot of money for after it had an expensive rebuild, but it was smoking and spewing oil out. We tried all sorts of stuff, all to no avail, until I fitted another timing cover which had come with it and looked slightly different internally. That cured it instantly. Regarding pistons and rings, there are Indian made rings out there which look ok and I put a set in our 350 racer once - this was a learning curve - to find it smoked like a destroyer, with black goo dribbling out from the exhaust port. Some Hepolite piston rings fixed that problem. I mention this because Indian made rings would fit in your engine and could be the culprits? Cheers, Paul.

[vince]

Does the oil tank have a breather? with double capacity return pump your pressurising the tank and it will eventually stop the oil return. Does the oil return continually when you first remove the filler cap? A little test is remove filler cap and rubberband a plastic bag over the hole and see if it expands when engine is running.

[Tim NZ]

The oil tank is directly connected to the crankcase via small passage cut into the crankcase top face behind the inlet camshaft...


Plastic bag over the oil filler cap will not prove anything.

[Connie 60]

Sorry Tim I had a Blonde moment, the 6 bolt cover was from the 61 SM I no longer have and the spare SM cases I was refering to with the duck bill breather does have the 4 bolt type.
The NOS cases having been on the shelf for 50 odd years were pretty grubby so I cleaned them thoroughly particularly the oil ways so I hope I got that bit done ok. On closer inspection the upper return hole was a little obstructed by the timing chest gasket. But not enough to make too much diff I would have thought. I will doctor the gasket where needed and slightly recess holes in the timing cover but they do seem to match up pretty well.
I only have the Connie now and the spare SM cases whose timing cover has a a rielief valve in the base to relieve oil into the timing chest. I could block it off I spose to use the cover on the Connie as a test but am sure the cover is ok at this stage.
The pistons and rings were Hitchcock jobs ordered straight from the online parts book. I don,t know there make as I can,t remember the packaging. From memory the rings were just in a plastic snap lock bag and plain packaging for the pistons so I spose they are Indian!

[vince]

Connie 60, Is the oil tank pressurising as per my previous question?

[Connie 60]

Hi Vince
I dont think it is. Though I can' t check it atm as I have the timing cover with me and the bike is 400 km away. When the engine is cold there is no pressure and I don't think I have noticed anything unusual when I have checked return flow when hot. I had a lot of pressure with old cases with breather into tank roof so much so that the tank cap wept some oil on runs. If there was pressure I reckon the tank cap would let it out. As Tim said the vent from. the inlet cam tunnel would sort if it is not blocked by sealant when bolting the cases together which is easily done. I pressure tested mine on build up and it seemed ok.
Cheers Mike

[Norm]

I always remember Craig Jolly pulling his Meteor motor down many times because it was wet sumping only to eventually find the head had come off one of the screen screws and somehow got under the screen and blocked the scavenge hole