A method and system for monitoring at least one reciprocating machine having a crankshaft and at least one cylinder, comprising providing at least one sensor for monitoring the at least one cylinder, the sensor being in communication with at least one processor configured to measure at least one signal from the at least one sensor and to thereby determine an angular position of the crankshaft; selecting at least one subset of potential crankshaft angular positions; calculating at least one statistic associated with the at least one subset of possible crankshaft angular positions based at least partially on data from the at least one sensor; and automatically providing a user with at least one warning or automatically shutting down the machine if the at least one statistic exceeds at least one predetermined threshold; wherein, the at least one sensor comprises at least one acoustic emission sensor.