Two technicians are discussing camshafts.Technician A says that increased valve overlap is caused by camshaft lobe wear. Technician B says that most OHV engines have variable valve timing in order to improve performance and reduce emissions . Who is correct?

Question

Quizplus · Accepted Answer

Technician A is incorrect. Increased valve overlap is not caused by camshaft lobe wear. Valve overlap is the period of time when both the intake and exhaust valves are open at the same time during the engine cycle. This can be controlled by camshaft design.

Technician B is partially incorrect. While variable valve timing (VVT) can improve performance and reduce emissions, most OHV (overhead valve) engines do not have VVT. OHV engines typically have a simpler valve train design and do not require VVT to achieve their performance and emissions goals.

Two Technicians Are Discussing Camshafts