Rocker lubrication

[cinquecento]

Could someone please help to understand how the rocker lubrication works in this pic.

Oil under pressure from the pushrod enters the bush...but how does oil make its way to the load point at approx 6 o'clock when the valve opens.

I suspect it's due to a hydrodynamic wedge being create as the rocker rotates to open the valve...but when the rocker rotates back to its resting position, is there a another wedge created on the other side. This would imply a wedge basically bounces backwards and forwards as the valve opens or closes.

Any help or clarification would really be appreciated.

[stevieturbo]

The bush inside the rocker likely has spiralling or some means of oil passing

Either that or via the shaft itself.

Oil needed to the tip etc would be extremely small, many would not have any sort of forced oiling, just splash

[PhillipM]

I'd be amazed if it's fed from the pushrod, more likely as Stevie says it's flowing in from drillings in the rocker shaft?

[stevieturbo]

PhillipM said:

I'd be amazed if it's fed from the pushrod, more likely as Stevie says it's flowing in from drillings in the rocker shaft?

LS' and I presume quite a few others do feed oil up the pushrod.

[cinquecento]

Yes..it's definitely pushrod fed..as per the RHS oil gallery in the pic. The pushrod, rocker adjuster and bush oil hole is 3mm in diameter.

[PhillipM]

Interesting, seen a few too and never really noticed!

Not sure there'd be too much of a wedge actually forming under the rockers at most speeds, mixed mode mainly given the low surface speeds and oscillation - maybe just enough to help work the oil through the loaded area and out of the spray point there, the shaft clearance and any feed grooves are probably enough to keep the rest flowing - what does the shaft and inner surface of the rocker look like?

[cinquecento]

The shafts are perfect..the rocker bushes are very badly scored.

It's from a Rover V8 that's been changed to pushrod rocker oiling.