What method is used to verify crankshaft runout?

What method is used to verify crankshaft runout?

• A. Use a torque wrench to rotate.
• B. Mount a dial indicator on a fixed datum and rotate the crankshaft to measure journal runout against spec.
• C. Visually inspect under light.
• D. Use a straightedge across journals.

Answer: (B)

To verify crankshaft runout, you need a fixed reference and a sensitive measurement device that can detect lateral movement as the shaft turns. Mount a dial indicator on a fixed datum tied to the engine block or a bearing surface, with the indicator probe touching a crank journal or a master surface. Rotate the crankshaft smoothly through a full 360 degrees and observe the dial reading; the total deviation you see is the runout. Compare that value to the manufacturer’s specification to determine acceptability. This method provides a precise, quantitative measurement of how far the crankshaft is off-center as it turns. Using a torque wrench won’t measure runout, visual inspection cannot quantify it, and a straightedge across journals isn’t a reliable or standard way to assess runout.

To verify crankshaft runout, you need a fixed reference and a sensitive measurement device that can detect lateral movement as the shaft turns. Mount a dial indicator on a fixed datum tied to the engine block or a bearing surface, with the indicator probe touching a crank journal or a master surface. Rotate the crankshaft smoothly through a full 360 degrees and observe the dial reading; the total deviation you see is the runout. Compare that value to the manufacturer’s specification to determine acceptability. This method provides a precise, quantitative measurement of how far the crankshaft is off-center as it turns. Using a torque wrench won’t measure runout, visual inspection cannot quantify it, and a straightedge across journals isn’t a reliable or standard way to assess runout.