I know it's been discussed before, but I thought I'd re-check my rocker shafts. When I looked before, there was *some* oil getting to the top of the engine, but it didn't seem to be a lot. I know these engines don't have oil sloshing around everywhere, but I was expecting to see some. I popped the rocker covers off again, one at a time, and fired the engine up. I couldn't really see much evidence of oil coming out of the rocker bosses, (I'm assuming the little holes either side are for oil to come out of?). I took the rocker shafts off, and poked around the two main oil ways at the ends of each side with a pipe cleaner, and noted that both the rear oilways were sludged up. Cleaned them out with a fresh pipe cleaner soaked in engine degreaser. I then turned my attention to the rocker shaft itself; I put it in the parts washer and washed it through with a diesel/paraffin mix. I used some rubber bungs to block up the bolt holes, which helped the washer fluid get right through. Refitted the rocker shafts and fired the engine up, but still couldn't see much evidence of oiling going on. The only thing I could see was a slow migration of oil in the bottom of the rocker chest moving towards the back of the engine on both sides, and most of the rockers seemed to have some oil weeping out around the rocker arms, but not all of them, and not from the little holes. I would have thought the parts washer should have shifted any gunk through. There didn't seem to be any play in the rocker arms, and all seemed free, and the engine runs quietly. What's the best thing to do...?