What tool is used to measure the side clearances of piston rings?

The thickness gauge is specifically designed to measure the clearance and the specific thickness of materials, making it the ideal tool for measuring the side clearances of piston rings. This tool allows for a precise measurement in small increments, essential in ensuring that the piston rings fit properly within their grooves and maintain the correct operating conditions. Proper side clearance is crucial for engine efficiency, as it helps control oil flow and reduces the risk of piston ring wear or damage.

While other tools like micrometer calipers and vernier calipers could provide measurements, they are typically used for measuring external dimensions or can lack the specific thinness required for accurate clearance readings encountered in piston rings. Rulers are less precise and not suitable for the fine measurements needed in engine components, which require more specialized tools for accurate assessment. Thus, the thickness gauge stands out for its purpose and functionality in this particular application.