The head on my 2wd saphire has developed a loud tappety noise which I thought may be a broken tappet, but after replacing the tappets (a couple did seem solid) the noise is still there.

I've taken the cam cover off and turned the engine over and you can here a distinctive metallic click/tap on the exhaust valves on cylinder 4.
When I took the cams out the inlet side has a lot more oil lying in the head than the exhaust side and it seems that the exhaust side is not getting fed enough oil.

It would seem that the oilway is blocked somehow or is there any other cause. The engine has good oil pressure.

Is this a common problem?

What's the best way of testing/unblocking the oilways or sorting the problem?


Cheers

Gordie