Rocker arm assembly

A valvetrain assembly comprising:

• a first engine valve;
• a second engine valve;
• a valve bridge operatively associated with the first and second engine valves;
• and
• a combined rocker arm assembly configured to selectively open the first and second engine valves, the combined rocker arm assembly comprising:
• a rocker arm body;
• an exhaust rocker arm assembly formed in the rocker arm body;
• a lost motion spigot assembly operatively coupled to the exhaust rocker arm assembly via a first bore formed in the rocker arm body, the lost motion spigot assembly including an adjustment nut and a guide which cooperate so as to define an internal bore;
• a shaft assembly arranged in the internal bore below an upper surface of the adjustment nut, the shaft assembly configured to adjust a lash of the lost motion spigot assembly;
• and
• an engine brake rocker arm assembly formed in the rocker arm body, the engine brake rocker arm assembly configured to alternately operate in a collapse mode and a rigid mode,
• wherein the lost motion spigot assembly is configured to selectively engage the valve bridge so as to open the first and second engine valves,
• wherein the engine brake rocker arm assembly is further configured to selectively engage the valve bridge so as to open only the first engine valve when operating in the rigid mode,
• wherein the adjustment nut includes a T-shaped cross-section,
• wherein a portion of the internal bore at the adjustment nut is threaded except for a portion of the internal bore corresponding to an upper flange portion of the T-shaped cross-section that is not threaded,
• wherein the shaft assembly includes an upper shaft and a lower shaft collectively extending through the guide, and
• wherein the upper shaft is threaded to the threaded portion of the internal bore at the adjustment nut.

A valvetrain assembly comprising:

• a first engine valve;
• a second engine valve;
• a valve bridge operatively associated with the first and second engine valves;
• a combined rocker arm assembly configured to selectively open the first and second engine valves, the combined rocker arm assembly comprising:
• a rocker arm body;
• an exhaust rocker arm assembly formed in the rocker arm body;
• a lost motion spigot assembly operatively coupled to the exhaust rocker arm assembly via a first bore formed in the rocker arm body, the lost motion spigot assembly including an adjustment nut and a guide which cooperate so as to define an internal bore;
• a shaft assembly arranged in the internal bore below an upper surface of the adjustment nut, the shaft assembly configured to adjust a lash of the lost motion spigot assembly;
• and
• an engine brake rocker arm assembly formed in the rocker arm body, the engine brake rocker arm assembly configured to alternately operate in a collapse mode and a rigid mode,
• wherein the lost motion spigot assembly is configured to selectively engage the valve bridge so as to open the first and second engine valves,
• wherein the engine brake rocker arm assembly is further configured to selectively engage the valve bridge so as to open only the first engine valve when operating in the rigid mode,
• wherein the guide includes:
• a first step configured to interface with the adjustment nut;
• a second step configured to interface with a biasing mechanism;
• and
• a third step configured to engage a stop surface formed on the rocker arm body,
• wherein the first bore includes a shoulder configured to cooperate with the second step so as to define a first biasing mechanism seat for the biasing mechanism, and
• wherein the exhaust rocker arm assembly includes a cap configured as a second biasing mechanism seat for the biasing mechanism.