25105687
Outer Cam
Mack

The outer cam is a critical element in certain camshaft assemblies, functioning as the mating surface or lobe that drives valve lifters or followers in the initial phase of valve timing. In engines with modular cam designs, an outer cam can influence the timing accuracy, lift profile, and overall valve train dynamics. Worn or damaged outer cams lead to reduced engine efficiency, rough idle, and loss of power, especially under heavy load. Replacement requires exacting tolerances and precise alignment with the inner cam and rocker assemblies to restore correct valve timing. Inspect for pitting, scoring, or uneven wear, and ensure the timing marks align during service. This part is essential for maintaining optimal combustion events and predictable throttle response in demanding operating conditions. Choose a part matched to your engine family and revision level to avoid mis-timing or performance gaps. Source One Parts Center supports your maintenance with trusted outer cam components.