🔍 Key Concepts

• Relationship between camshaft and crankshaft in a four-stroke engine • How many crankshaft revolutions occur in one complete four-stroke cycle (intake, compression, power, exhaust) • How often the valves need to open and close during that full cycle

💭 Think About

• First, count how many strokes are in the cycle and how many crankshaft revolutions are needed for those strokes. • Ask yourself: during those strokes, how many times should each valve (intake/exhaust) open and close? • From that, decide whether the camshaft needs to turn faster, slower, or the same speed as the crankshaft to match proper valve timing.

✅ Before You Answer

• Be clear on: 1 full four-stroke cycle = how many crankshaft revolutions? • Check that your chosen camshaft speed would make each cam lobe operate a valve the correct number of times per full cycle. • Eliminate any option that would make the valves open too often or not often enough for each full engine cycle.