The 318is engine was designated M42B18 and was derived from the 318i M40 block (made from pearlitic gray cast iron) with siamesed cyliner bores and integral oil jets monuted in big ends 2, 3, 4 & 5 for piston cooling and gudgeon pin lubrication. Big ends bearing are of the three layer type. The complete engine ended up 13kg heavier and 30mm taller than the M40. The chilled-cast aluminium alloy 16 valve twin cam head is a classic pentroofed design with the spark plug centred between the valves...