Arrangement of an engine with a generator

The arrangement has a cylinder casing (12) and a timing cover (11) that form housing (3) for valve gear drive units (4). An alternator (5) is connected to the casing and the cover. The alternator has lugs (6) whose forward movement does not reduce the width of a sealing surface (17) of the housing. The surface extends in a tab (7) between the lugs.