🔍 Key Concepts

• Valve lash (valve clearance) and how it affects the timing of when the cam actually starts to move the valve • The relationship between cam lobe position, tappet/rocker arm motion, and when the valve begins to open and finishes closing • What happens if there is more clearance between the valve train parts than the manufacturer intended

💭 Think About

• Picture the cam lobe rotating: if there is extra clearance before it contacts the rocker/valve, does the valve start to move earlier or later in the cam’s rotation? • Once the cam has passed its maximum lift and starts to close, with extra clearance in the system, will the valve stay in contact with the cam longer or will it lose contact and seat earlier? • Compare normal clearance vs excessive clearance: in which case does the valve spend less total time off its seat?

✅ Before You Answer

• Be clear on what "excessive" valve lash means: more clearance than specified, not less • Think about whether increased clearance causes shorter or longer valve open duration overall • Verify mentally: does the valve begin opening after the cam lobe starts lifting (delay) and return to the seat before the cam lobe has fully finished its closing ramp when lash is excessive?