What tool is used for compressing the valve spring for removal and insertion?

The tool used for compressing the valve spring for removal and insertion is a valve spring compressor. This specialized tool is designed to safely and efficiently compress the spring, allowing the valve keepers (or locks) to be released or installed without damaging the springs or the engine components.

A valve spring compressor typically features two arms that grip the valve spring and a mechanism to apply pressure, making it easier to manipulate the spring during maintenance tasks. This is crucial because working with valve springs involves a significant amount of force, and proper handling is necessary to avoid injury or damage.

In contrast, the other tools listed, such as a piston puller, cylinder clamp, and spring puller, have different purposes. A piston puller is used to remove pistons from the engine, while a cylinder clamp is primarily used to hold the cylinder in place during various operations. A spring puller is generally employed for removing external springs, not specifically designed for valve springs. Therefore, the valve spring compressor is the only appropriate choice for this task.