Abstract: Increasing the diameter of cylinder bores in a cylinder block requires a longer and heavier cylinder block to accommodate the larger bores. If the cylinder block is not lengthened it is difficult to accommodate the water jacket between the outermost cylinder bore and the cylinder block end wall. The cylinder block of the present invention has an upper part including a number of cylinder bores surrounded by a water jacket. The upper part also has first and second end walls which are generally co-planar with first and second end walls of a lower part of the block, but include projecting portions adjacent the top deck. The projecting portions may curve outwardly from the first and second end walls and generally follow the curvature of the two outermost cylinder bores on the block. By providing the projecting portions on the first and second end walls, a minimum width of water jacket can be accommodated without significantly increasing the length and overall size of the block.

Abstract: An oil cooler (1) is removably mounted on the side of an engine block (13) with a tubular coolant flow coupling (19) received as a push-fit in an aperture (18) in the block so that the coolant flow connection is simply made as the oil cooler is fastened to the side of the block. The coupling (19) may be a push-fit in respective axially aligned apertures (18,20) in the block and the cooler. The flow coupling may be an inlet coupling for coolant from the block. The end of the coupling that cooperates with the block has an extension (24) that projects into a coolant flow passage (17) in the block and is shaped to form an inlet opening that is directed laterally of the axis of the coupling and upstream of the coolant flow in said passage. The extension (24) collects coolant from said passage and produces a pressure drop in said passage.