To notify a driver of a possibility that a combustion condition is deteriorated or fuel consumption is increased due to a shift of cam phase involved by elongation of a timing chain and to store it as data for a vehicle inspection.

An engine rotatively drives a crank shaft (7) and cam shafts (11,12) by the timing chain and comprises an ignition timing processing means (31) for calculating optimum ignition timing and a spark ignition means (6) for performing spark ignition in conformity with the optimum ignition timing. The engine is equipped with a cylinder pressure sensing means (32) for detecting cylinder pressure and a determination means (31) for judging if the timing chain is elongated or not based on a detection value of the cylinder pressure.

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