Airborne Flying Services of Hot Springs, Ark., developed and now offers the Valve Wizard, a set of three valve spring compressor tools for Lycoming O-235, O-290, IO/O-320, IO/O-360, AEIO-360, O ...

Here are two common valve spring compressors for use with the heads still bolted to the engine. The stamped steel compressor (top) is fast and convenient for most stock valve springs.