Rocker Shaft Orientation

[Terryb]

Need some advice please.
I’m assembling my A10 rocker box and noticed the rocker shafts have an oil channel running along its length. Can’t find any info on the orientation of this slot, when re-assembling. Help please?

[morris]

I always mount them oil channel upwards.
The reason behind it is that the oil then comes out from above and thus doesn’t have to work it’s way up to lubricate the rockers.
That’s my theory anyway 

[Terryb]

He’s, that makes sense. I’m surprised that it’s not recorded in any Service Sheets or after market manuals. I’ll follow your advice, many thanks👍

[BagONails]

Putting mine back together now and this question occurred to me so I did a quick search and this was the only thread that came up.

It may be that this doesn't really matter but I'm sure BSA wouldn't have left this to chance...would they?

My feeling is that the oil supply is most needed on the underside of the rocker shaft as it is there that the shaft and rockers react the forces coming from the push rods working against the valve springs. Most friction and wear you would expect to occur on the underside of the shafts and rocker bearing bores. I notice there are oil drain drillings in the rockers too on the underside, presumably to aid oil flow.

Final clue I have found is on page 21 of the owner's instruction manual where the exploded drawing shows the valve gear all laid out in as you would expect the correct orientation in vehicle. This shows the rocker shafts with the oil delivery channels facing DOWN.  I'm not worried about gravity so much because the oil is delivered under pressure.

Per my reasons above and what's shown in the drawing, I'm putting mine in channels down, sorry guys! 

But as I said at the start we all end up over thinking these things and to be honest it probably doesn't make an iota of difference whichever way they go. This is about the only part of my bike I've worked on that hasn't been shagged out so I'm thinking this is one of the more robust areas of the unit! Cheers 

[limeyrob]

On anything with an oil "in" and oil "out" holes I would put the "in" opposite side to the holes.  This means the oil has to travel around the shaft to drain, cannot take a shortcut to the drain holes missing the bearing surface.

[muskrat]

G'day BON.
I'm with Rob on this one. My reasoning the same plus if the groove is down there is less area making contact meaning more wear. As the rocker is only under load about 1/3 of the time allows oil to flow towards the drain holes. There is bugga all pressure feeding the rockers.
Cheers

[BagONails]

Yes all good points thanks Rob and Musky. I was having second thoughts as I assembled things yesterday when I also realised the radial grooves line up with the spit holes so there is a direct communication from delivery side out of the two holes in the middle of the shaft, along the axial channel then around the radial ones at each end to the spit holes.  With those holes being much bigger than the inlets at the banjo there can't be any pressure much at all as you say...so I had a change of heart and turned them 180 degrees!  I guess the spit holes are there to encourage some oil to dribble under the rocker arms and onto the valve stems.

Whatever, a local guru said he'd never given it any consideration and never worried about the orientation, not seen a lubrication problem with the rockers on these either.