Valve lash adjustment state: closed.

Valve lash adjustment state: closed.

• A. Open
• B. Closed
• C. During valve overlap
• D. With timing belt removed

Answer: (B)

Valve lash is the clearance between the valve stem and the rocker or lifter when the valve is fully closed and seated against its seat. The adjustment must be done with the valve closed because, at that moment, the valve is not being moved by the cam, so you’re measuring the true static clearance. If you tried to set it with the valve open or during overlap, the cam lobe, lifter, and rocker are in motion and the clearance would be measured at an incorrect point in the cycle, leading to improper lash. The timing belt being removed isn’t part of the adjustment state; lash is set with the timing components installed and the cylinder positioned so the valve is fully closed.

Valve lash is the clearance between the valve stem and the rocker or lifter when the valve is fully closed and seated against its seat. The adjustment must be done with the valve closed because, at that moment, the valve is not being moved by the cam, so you’re measuring the true static clearance. If you tried to set it with the valve open or during overlap, the cam lobe, lifter, and rocker are in motion and the clearance would be measured at an incorrect point in the cycle, leading to improper lash. The timing belt being removed isn’t part of the adjustment state; lash is set with the timing components installed and the cylinder positioned so the valve is fully closed.