One method of determining crankshaft...

🔍 Key Concepts

• Crankshaft alignment vs. wear – what measurement shows bending/sagging of the shaft, not just bearing clearance • How crank drop is checked on large marine engines using a dial indicator as the shaft is rotated • Difference between checking parallelism of webs/cheeks and checking if the shaft has sagged or is misaligned in the bearings

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• Which method directly shows if the crankshaft centerline is no longer straight or level as it turns in its bearings? • Which options mainly measure bearing clearances or distances between cheeks, and which one looks for vertical change (sag) at each throw during rotation? • On a large slow‑speed marine diesel, what routine test is recorded in a log sheet to monitor if the shaft is bending or the bedplate is settling?

✅ Before You Answer

• Identify which choice involves measuring vertical movement at the crankpin while the shaft is rotated • Distinguish methods that check bearing clearance from those that check shaft straightness/alignment • Ask: which procedure is standard practice on large marine engines for checking crank alignment over time?

One method of determining crankshaft misalignment is by __________.

laying a straight edge across the crank webs at the crank pin and measuring the distance to the crank pin in two places

taking micrometer readings between the crank cheeks opposite the crank pin every 90° of crank angle rotation

measuring the crank drop on either side of each crank throw while the crankshaft is slowly rotated through one revolution

rotating the crankshaft through one revolution, pausing each 90° of rotation to measure bearing clearances, top and bottom

🔍 Key Concepts

💭 Think About

✅ Before You Answer