Abstract: Disclosured herein are apparatus and methods relating to combustion engines. In an example, a combustion engine includes a head and a rocker assembly. The rocker assembly including: a rocker shaft including therein a pressure reservoir, a pedestal support adapted to be fastened to the head and sized and structured to support the rocker shaft, a rocker lever pivotally supported by the rocker shaft, and a hydraulic engine brake mechanism within the rocker lever including a hydraulic control valve configured to selectively actuate an exhaust valve of the combustion engine.