A system for controlling the timing of a cylinder valve in a reciprocating internal combustion engine includes a crankshaft position sensor for determining position of the crankshaft, and a camshaft structural force sensor for determining the presence of a structural force upon the camshaft related to a unique rotational position of the camshaft. A controller receives position signals from the crankshaft and camshaft structural force sensors. The controller compares the valve position signal from the structural force sensor with a predicted valve position based upon the crankshaft position and determines if the predictive value is in error. If an error is greater than a specified threshold, the predictive model will be corrected.