UENR4490-01 11 Engine Operation The connecting rods (4) are machined from forged steel. The connecting rods have bearing caps (6) that are fracture split. Two connecting rod bearings (5) are installed between the connecting rod (4) and the bearing cap (6). The bearing caps on fracture split connecting rods are retained with Torx bolts (7). Connecting rods with bearing caps that are fracture split have the following characteristics: A gear at the front of the crankshaft drives the timing gears. The crankshaft gear turns the idler gear which then turns the following gears:
Camshaft gear Fuel injection pump and fuel transfer pump The idler gear is driven by the crankshaft gear which turns the gear of the lubricating oil pump. The splitting produces an accurately matched surface on each side of the fracture for improved strength. Lip type seals are used on both the front of the crankshaft and the rear of the crankshaft. The correct connecting rod must be installed with the correct bearing cap. Each connecting rod and bearing cap have an unique serial number. When a connecting rod is assembled the serial numbers for the connecting rod and bearing cap must match. A timing ring is installed to the crankshaft.
The timing ring is used by the ECM in order to measure the engine speed and the engine position. A ring gear for the balancer can be installed to the crankshaft. When a balancer is installed, the engine oil pump is an integral part of the balancer assembly. The ring gear for the balancer drives the balancer. Crankshaft Gears and Timing Gear Case Illustration 8 g02155439 Typical example Illustration 9 g02212814 Typical example (1) Crankshaft gear (2) Crankshaft (3) Crankshaft thrust washers (4) Crankshaft timing ring (1) Hole for the water pump gear (3) Position of the accessory drive gear The crankshaft can be a spheroidal graphite iron casting or a steel forging.
The crankshaft oil seal is mounted in the cover of the timing case. The timing case cover is made from sound-deadened steel or cast iron. The crankshaft has five main journals. Thrust washers are installed on both sides of number 3 main bearing in order to control the end play of the crankshaft. The timing gears are made of steel. The crankshaft gear (5) drives an upper idler gear (4) and a lower idler gear. The upper idler gear (4) drives the camshaft gear (6) and the fuel injection pump gear (2). The lower idler gear drives the oil pump. The water pump drive gear is driven by the fuel injection pump gear.
The crankshaft changes the linear energy of the pistons and connecting rods into rotary torque in order to power external equipment.