09000-09421 PUMP ASSY, INJECTI Denso Cross

1.1 Engine Proper
(1) Combustion chamber The combustion chamber is made up of the cylinder head and piston top. The hole type injection nozzle as well as the nozzle tube is mounted on the cylinder head. The nozzle tube holds the nozzle in position and protects the nozzle from coolant. Since the outside of the nozzle tube is exposed to the water jacket, the top end of the tube is sealed off with an O-ring and the bottom end staked to prevent entrance of water.Combustion is accomplished by compressing the fuel directly injected into the combustion chamber.On 6D15 and 6D15-T engine, a valve recess is provided at the cylinder top to ensure clearance between piston and exhaust valve.(2) Valve mechanism (a) Both the intake and exhaust valves are made of surface-treated heat-resistant steel. The valve seat angle is 45° for both valves. Valve stem seal is mounted to the valve stem, which controls the amount of lubricant on the sliding surfaces between the valve and valve guide.A valve guide with carbon cutter is used for the exhaust valve.(b) Two unevenly pitched valve springs are used to prevent chattering at high speed. The inner and outer spring coil directions are opposite to each other.(c) The rockers are made of precisely forged carbon steel. The end sliding portions of the rockers has been quenched. The rocker shaft is a hollow round rod sealed off with expansion plugs at both ends. The inside of the shaft serves as an engine oil passage.(d) The push rod has a steel ball welded to its bottom end and a spherical or depressed piece welded to its top end. Both ends are carburized case-hardened. (e) The tappet is of cylindrical shape. Its mating surface with the camshaft is a large-diameter sphere to prevent local wear. The tappet can be removed by removing the cylinder head without removing the camshaft.(f) Excellent reliability at high speed has been achieved by adopting a high camshaft which permits the use of shorter push rods with high rigidity.(g) To facilitate the insertion and removal of the camshaft from the rear end of the case, the bearing I.D. is narrower toward the front.(3) Crankcase and cylinder liner (a) The crankcase is made of cast iron, provided with ribs to ensure high rigidity, and built with minimum stress concentration and deformation.(b) The oil main gallery is located on the right side as viewed from the front and supplies the engine oil that has passed through the oil filter and oil cooler to various sections. Engines other than the 6D14 and 15 series have an oil jet provided for each cylinder to cool the piston.(Refer to Group 12 LUBRICATION.)(c) Cooling water that has entered the water jacket cools the cylinders before it flows to the cylinder head. (d) The cylinder liner other than 6D16, 6D16-T engines is of the wet type that is removable. It engages with the crankcase at the top of the crankcase and at the bottom of the water jacket.