Cylinder head oil starvation
We’ve currently got some cylinder heads in our workshop for overhauling.
It’s not unusual for us to to be doing this type of work, but these particular heads have highlighted a problem which can affect most engines.And the results can be catastrophic.
It was during the inspection of the rocker gear that we found some of the oilways on the rocker posts were blocked with carbon deposits:
If the rocker posts had not been removed and treated as individual components, this blockage would have been missed and the restricted oil flow would have continued, leading to the seizure of the rocker gear and possibly further engine damage.
This happens because before the oil reaches the rockers, it is fed from the cylinder head up the rocker post and they are designed in such a way that over time the oil has pooled in this area, and gradually hardened following numerous heating cycles.
If you are dismantling assemblies, make sure every part is removed and properly checked, with particular attention to the oilways.