What instruments are typically used to inspect a cylinder barrel for out-of-roundness?

The use of a dial indicator or inside micrometer is essential for inspecting a cylinder barrel for out-of-roundness because these instruments provide precise measurements critical to assessing the cylinder's shape. A dial indicator is particularly effective for detecting minute variations in the diameter around the cylinder's circumference, which is crucial for identifying any deformation or irregularities that could affect engine performance and sealing.

An inside micrometer can measure the internal diameter of the cylinder's bore with high accuracy, enabling you to determine if the cylinder is consistently round and meets the required specifications. It is designed for this specific application, unlike other tools mentioned, which are less suited for such precise internal measurements.

The other instruments listed are not appropriate for measuring out-of-roundness in a cylinder barrel. For example, a torque wrench and caliper are more suited for checking fastener tension and external measurements rather than internal dimensional accuracy. Likewise, an impact wrench is used for applying torque rather than measuring, and a ruler would lack the precision needed to assess small variations in diameter accurately.