Low oil pressure after shim

[Signature620]

The pressurised oil is supposed to travel to the head from the block, then to the cams, then to the rockers. So when a cam bearing spins it will increase it's diameter and/or shift forwards or backwards. This allows oil that would normally be under pressure between the cam and rockers to be released into the overhead, so much that the oil pump can't keep up, lowering the general oil pressure.