I built this for working on changing valves. Wasn't thrilled with the options available for compressing valve springs on M62 and made my own based on a $12 HF "universal" tool and a piece of copper pipe.
I cut off one hook, modified the other side so it actually holds, I cut a slot that hooks onto the outside stud between the cylinders. Very happy with the results.
I found a piece of plastic pipe that goes around the copper to make sure it stays centered. Awesome.