What is the function of a valve spring compressor?

The function of a valve spring compressor is primarily to assist in the installation or removal of valve springs from the cylinder head. When working on small engines, it's essential to be able to compress the valve springs so that the retainers can be removed or installed without damage to the components. The valve spring compressor provides the necessary leverage and force to safely compress these springs, allowing for straightforward access to the valves and other components.

While alignment of valve springs and measurement of spring tension are important tasks in engine maintenance and repair, they are not the primary functions of a valve spring compressor. Additionally, removing valve seats is a separate process that does not involve the use of a valve spring compressor, as seats are typically pressed into the engine block or cylinder head and require different tools to remove.