🔍 Key Concepts

• Rotating vs. reciprocating forces in an engine (what needs to be balanced) • How crankshaft balance affects loads on the main bearings • Difference between side thrust, end thrust, and bearing loading

💭 Think About

• Think about what part of the engine the counterweights are attached to and what motion they are trying to balance. • Which component(s) will feel more stress if the crankshaft is not properly balanced during rotation? • Ask yourself: what type of load would become more even if the rotating assembly is properly counterweighted?

✅ Before You Answer

• Be clear on what piston side thrust is and what causes it. • Understand how unbalanced rotating masses affect the main bearings during each revolution. • Verify which option talks about a condition that directly results from an unbalanced crankshaft rather than from piston motion or structural strength.