to a front end of a cylinder head of each bank of the v type engine designated by numeral 6 is a rocker cover which covers both a cam shaft 5 and various valve parts driven by the cam shaft 5 designated by numeral 7 is an oil pan which reserves a lubricating oil of the engine designated by numeral 10 is a bearing cap for a crankshaft 8 the crankshaft 8 has a cranksprocket 9 secured thereto respective idler sprockets 11 are rotatably connected through shafts 19 to the respective cylinder blocks 2 a chain 13 is operatively put on the cranksprocket 9 and the two idler sprockets 11 each cam shaft 5 has a cam sprocket 14 secured to a front end thereof a chain 15 is operatively put on the cam sprocket 14 and the corresponding idler sprocket 11 thus rotational power of the crankshaft 8 is transmitted to the two cam shafts 5 through the respective idler sprockets 11 to a front end of the crankshaft 8 there is secured through a bolt 17 a crankpulley 16 a belt not shown is operatively put on the crankpulley 16 and known auxiliary devices not shown so that the auxiliary devices are powered by the crankshaft 8 as is seen from fig2 a front cover structure 1 is attached to the front ends of the two cylinder blocks 2 having the crankpulley 16 exposed to the outside of the engine for achieving this attachment the front cover 1 has an aperture no numeral through which the front end of the crankshaft 8 passes a seal ring.