🔍 Key Concepts

• Crank web deflection: what it measures in a crankshaft and why engineers take these readings • Relationship between deflection and bending/straightness of the crankshaft rather than wear size alone • Which components affect crankshaft alignment: main bearings vs. thrust bearings vs. bearing shims

💭 Think About

• Ask yourself: when you put a dial indicator on crank webs and measure deflection at different positions, what problem are you really checking for? Alignment, axial clearance, or bearing thickness? • Think about which part of the crankshaft’s support system, if worn or damaged, would cause the crankshaft to bend or sag and change web deflection readings. • Compare: thrust bearings mainly control end play (axial movement). Would axial movement be what web deflection readings directly show, or is it something else?

✅ Before You Answer

• Be clear on the difference between radial bending/straightness and axial end play of the crankshaft. • Decide which of the listed options would most directly cause a change in measured web deflection rather than just a change in bearing clearance or shim size. • Mentally picture how crank webs move when the crankshaft is misaligned versus when thrust bearings are slack or shims are altered. Which motion would a deflection gauge actually record?