I like my mechanical valve spring compressor that looks like a giant c-clamp, Mines got a tension clamp that holds it in the open position. I think I am going to find the right size piece of pipe and cut some access holes in it. drill press plus this thing is GREAT http://www.goodson.com/CF-12-125_Diameter_Valve_Spring_Adaptor/
i really need to snap some pics of my valve spring tool..it works soo amazing..