Valve lash is necessary to allow for

• A. Cam profile wear
• B. Piston expansion
• C. Valve expansion
• D. Cylinder bore wear

Answer: (C)

Valve lash is there to accommodate thermal growth of the valve and its related components. When the engine heats up, the valve stem, valve seat, and surrounding parts expand. If there were no clearance, they could bind or contact each other, preventing the valve from seating properly or even causing damage. Setting a small gap when cold ensures there’s room for that expansion so the valve can open and close smoothly and seal correctly when hot. It isn’t about cam profile wear, piston expansion, or cylinder bore wear.