The crankshaft converts the linear motion of the pistons into rotational motion. The crankshaft drives a group of
gears (front gear train) on the front of the engine. The front gear train provides power for the following components:
Engine oil pump
Fuel transfer pump
The crankshaft is held in place by seven main bearings. The oil holes and the oil grooves in the shell of the upper
bearing supply oil to the connecting rod bearings. The oil holes for the connecting rod bearings are located at the
following main bearing journals: 2, 3, 5, and 6.
Hydrodynamic seals are used at both ends of the crankshaft to control oil leakage. The hydrodynamic grooves in
the seal lip move lubrication oil back into the crankcase as the crankshaft turns. The front seal is located in the
front housing. The rear seal is installed in the flywheel housing.
The camshaft (Figure 3, Item 1) has three lobes at each cylinder in order to operate the unit injector, the exhaust
valves, and the inlet valves. Seven bearings support the camshaft. The camshaft is driven by an idler gear that is
turned by the crankshaft in the front gear train. Each bearing journal is lubricated from the oil manifold in the
cylinder block. A thrust pin that is located at the rear of the block positions the camshaft through a circumferential
groove. The groove is machined at the rear of the camshaft. Timing of the camshaft is accomplished by aligning
marks on the crankshaft gear, idler gear, and camshaft gear with each other.
Figure 3. Camshaft.