SOS Mechanic Certificate – Engine Repair Practice Exam 2026 - Free Engine Repair Practice Questions and Study Guide

When using plastigage to examine bearing inserts, the measurement it provides can help determine the clearance between the insert and the corresponding crankshaft journal. If Insert "A" shows more clearance than expected, this suggests that the insert may not fit properly in its designated location.

An increased clearance often indicates that the insert has worn down or that there has been some misalignment or damage, thereby resulting in a deviation from the manufacturer's specifications. Bearings are designed to function within specific tolerances; hence, if the clearance exceeds those tolerances, it signifies that the insert is not performing as intended. This situation can lead to inadequate lubrication and increased wear, potentially causing engine failure over time.

In summary, more clearance than what is specified usually means the insert is out of tolerance and may need to be evaluated for replacement to ensure the engine continues to operate effectively and reliably.