B26 pre OIF, oil hole mystery?

[Barney Rubble]

Hello again folks. Just replaced the kickstart spring on my motor, and have observed that there is a small hole in the inner timing case from which oil issues, when the engine is turned over. It is about .020", looks like a drilling, and the engine only has to be turned a couple of degrees to put oil out of it. I have found no reference to this, and need to know if it meant to be there! I have attached (or tried to), a diagram of where it is, approx. So, is this a defect, is it engine oil (as it seems to be pumped), or is it something else?

In the manual, it is digam B25, (the manual downloaded from here IIRC), it looks to be just visible as a dot between the gearchange shaft, and the screw head to its' right.
Thoughts please- Have I missed something, or do I have a pinhole that needs plugging? Thanks as usual for your help, folks!
Off now to a VJMC show (traitor!!) as the sun is out and it's hot! And I need to make some blue smoke.....

[JulianS]

The little hole allows oil expelled from the breather to be readmitted to the crankcase.

[Barney Rubble]

Ingenious! just that it looked like it was coming from the pump, the way it pulsed. I guess it will find its own level (or will it??) in the space between inner and outer timing cases. Shoul it make its way back into the engine oil system somehow? if left to constantly drain, it would bleed it all into the caes, then? I can't tell if it gets scavenged from the lube diagrams, so wondered if this hole should be there, and is it a problem that it runs oil out? It has been a very long time since I was in one of these engines- over 40 years in fact. Hmmm. Cheers, Julian.

[JulianS]

The hole should be below the oil level in the sump.

Sump is not an oil resevoir and should not be very much there.

[Barney Rubble]

Wet sumping- not wanted, lol.
So,  am I correct in saying, what comes from the sump, via this hole, ends up by default adding to gearbox level?
And if persistent, lowers the oil tank level?
More to worry about!

[JulianS]

You can check for wet sumping by removing the sump cover.

The oil which you may find between the inner and outer timing cover does not go to the gearbox, there is not oilway between them.

It is worth reading the most excellent book by Rupert Ratio - Unit Single engine manual. It explains the hole and very much more.

[Barney Rubble]

I'll have to get the book. I just thought that if it persists in wet sumping (indicating another problem elsewhere, maybe a NRV, which sticks) it could be a problem. I expected the oil, if sufficient amount, to infiltrate the gearbox via the camplate slot or some such, if if it got high enough. Not worried about wet sumping, I know they will all do a bit over time, and I don't think mine is particularly bad in this respect. Mystery solved, pretty much! Thanx Julian.