Engine

The present invention relates to such an engine as mentioned below. The engine comprises a belt transmission device (2) which interlockingly operates a cooling fan (1) and a timing transmission device (4) which interlockingly actuates a fuel injection pump (3). The belt transmission device (2) and the timing transmission device (4) are dividedly arranged at a front end and a rear end of a cylinder block (6), respectively. The fuel injection pump (3) is arranged on one horizontal side of the cylinder block (6) and a belt tensioner (7) of the belt transmission device (2) is disposed in front of the fuel injection pump (3).