Originally Posted by Frank Reiner

While using a dial indicator to measure the movement of a valve provides an admirable degree of accuracy, the reliance upon the production marks from the factory to determine the position of the crankshaft tends to negate the usefulness of the indicator's accuracy.

Who is to say that the pointer is correctly located in the front of the chain case? Who is to say that the circumference of the balance disc or torsional dampner is correctly marked for TDC or the number of degrees before or after? If TDC has not been verified for all of the specific components (crankshaft, balance disc/dampner, pointer) then only one part of the reference, the valve lift, is accurately known. Crankshaft position is not accurately known.