What way does the rocker shaft oil hole face?

Reassembling the head, I wanted to ask what way does the flat spot with the oil hole face? Facing the valves? or facing in to the center of the head....
Facing the center of the head looks like it's the correct way, the hole then alligns up with the oil drain hole in the rocker arm..But I wanted to double check.

Thanks!

rocker shaft orientation

From the NOC Commando Service Notes

"The rocker spindles are fitted with the oil flats outwards - away from the holes in the rockers - because otherwise too much oil swamps the head."

Not what you thought.

David

nidyanazo said:

Facing the center of the head looks like it's the correct way, the hole then alligns up with the oil drain hole in the rocker arm..

Click to expand...

Because a Commando's valve gear is supplied with high pressure oil from the supply side of the pump, instead of from the rather lower pressure scavenge side as was the norm for the majority of other British bikes (including Nortons before the last 1000 Atlas models that had the same arrangement as the Commando) not only would the valve gear be swamped with oil if the rocker spindles had the flats facing inwards, but there would also be a loss of oil pressure to the big ends, so the spindles always have the flats facing outwards.

Thanks!

Although it seems quite hard for that oil to migrate around the shaft to the "drain holes" in the rockers... It's quite a tight fit...
Is there another escape route for the oil?

nidyanazo said:

Is there another escape route for the oil?

Click to expand...

The oil could run along the spindles and escape, and I would expect a certain amount of oil gets out that way, but that's it.

I was always curious about this too and after playing with a couple of heads I came to the conclusion once the head warms up, the shaft radial clearance is considerably increased allowing the oil to migrate readily, also the oil will be hot and thinner as well.

On the original 1949 iron head Dominator they had a machined bore size fit for the rocker spindles and when they went to the first of the alloy heads they had serious oversize play (and leaks) requiring a re-dimensioning of the rocker spindle bores.