that's a nice animation & explanation. It is still difficult for me to tell just by sound if I have bad lifters since there is so much other noise in the valve train. I see on Jims website they recently introduced a new lifter diagnostic tool. I was thinking about buying it, but it is kind of pricey, in the mid to high $200 range. But it would be nice to know when you are swapping out cams or inspecting lifters, if they are working 100%.