When doing an inspection for valve stretch what tool should be used?

When doing an inspection for valve stretch what tool should be used?

• A. Contour or radius gauge
• B. Feeler gauge
• C. Dial indicator
• D. Micrometer

Answer: (A)

When inspecting valve stretch, you want to evaluate the actual shape of the valve stem’s rounded profile, not just a single linear dimension. A contour or radius gauge is used because it matches the various radii along the stem and tip, letting you see if the contour has changed from its original shape. If the stem has stretched, the radius at critical points will no longer match the known-good profile, and the gauge will reveal gaps or a poor fit along the stem. This makes it the most effective tool for detecting changes in the curvature that indicate stretch. Feeler gauges measure small gaps between surfaces, which isn’t what you’re checking here. A micrometer gives a single diameter measurement and doesn’t capture profile changes along the curved surface. A dial indicator can measure runout or displacement at a point but doesn’t map the full contour of the stem. So the contour or radius gauge directly addresses the need to verify the valve stem’s curved profile for stretch.

When inspecting valve stretch, you want to evaluate the actual shape of the valve stem’s rounded profile, not just a single linear dimension. A contour or radius gauge is used because it matches the various radii along the stem and tip, letting you see if the contour has changed from its original shape. If the stem has stretched, the radius at critical points will no longer match the known-good profile, and the gauge will reveal gaps or a poor fit along the stem. This makes it the most effective tool for detecting changes in the curvature that indicate stretch.

Feeler gauges measure small gaps between surfaces, which isn’t what you’re checking here. A micrometer gives a single diameter measurement and doesn’t capture profile changes along the curved surface. A dial indicator can measure runout or displacement at a point but doesn’t map the full contour of the stem. So the contour or radius gauge directly addresses the need to verify the valve stem’s curved profile for stretch.