The valvespring appears to be no more complicated than the spring that swings your screen door shut behind you. Granted, the concept is pretty simple, but in the context of the engine's valvetrain, ...

Many gearheads buy their cylinder heads fully assembled and don't have to sweat making sure all of the various parts are set up correctly. But for those that build their own, or that just need to swap ...

Those wound-up pieces of high-tensile steel under your rocker arms work so hard closing your valves over millions of cycles that they could probably use a replacement right about now. We're talking ...