The camshafts on the engine, shown in the...

The camshafts on the engine, shown in the...

Question 1 of 270705eccefa1bacbc34ba4d47647

The camshafts on the engine, shown in the illustration, operate at a speed equal to __________. See illustration MO-0005.

Question 1 of 27070

Q

The camshafts on the engine, shown in the illustration, operate at a speed equal to __________. See illustration MO-0005.

No Illustration

This question does not have an illustration

🔍 Key Concepts

• Relationship between crankshaft rotation and valve timing in a four-stroke diesel engine • How many crankshaft revolutions are needed to complete all four strokes (intake, compression, power, exhaust) • Gear or chain drive ratio between the crankshaft and camshafts in typical marine four-stroke engines

💭 Think About

• Look at the illustration and mentally follow one piston through all four strokes; how many times does the crankshaft turn while the intake and exhaust valves complete one full open/close cycle? • If the camshaft controls the valves for one complete engine cycle, how fast must it turn compared with the crankshaft, which controls piston movement? • Compare this to a two-stroke engine: would the camshaft-to-crankshaft speed relationship be the same or different, and why?

✅ Before You Answer

• Confirm from the illustration that this is a four-stroke engine (identify intake, compression, power, exhaust strokes). • Think about the number of crankshaft revolutions per engine cycle versus number of camshaft revolutions per engine cycle. • Eliminate any options that would cause the valves to open and close too often or not often enough for one full four-stroke cycle.