Originally Posted by gmog220d

I have, a few times on at least two OM616s. It is the best way to know cam timing accurately. You need a dial indicator that is scaled right for the measurement, and a way to hold it in place.

I used a magnetic base with jointed arm for holding the dial indicator in place. I bought a set of extensions for the rod to keep the tool above the rocker and cam, which provided a straight shot down to the valve retainer. It helps to use a longer tool for rotating the engine, so you have greater control and are less likely to overshoot the 2mm depth.