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TM 5-2410-241-23-1
FIELD MAINTENANCE
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THEORY OF OPERATION: ENGINE AND FUEL
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ENGINE
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Cylinder Block
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The cylinder block is a unique design with a deep counterbore that supports the cylinder liner. The cylinder block
also forms the coolant jacket. Two oil manifolds are provided in the cylinder block for engine lubrication. The
manifold on the lower right side of the cylinder block provides oil to the following components:
Piston cooling jets
Crankshaft bearings
Oil filter base
The manifold on the upper left side of the cylinder block provides oil to the following components:
Valve mechanism
The manifold on the right supplies oil to the manifold on the left. The oil travels through the cut above the number
one main bearing and the cut above the number four main bearing.
Cylinder liners (Figure 1, Item 1) are seated on a ridge (Figure 1, Item 4) in the middle of the cylinder wall between
the crankcase and the coolant jacket. The ridge is created by a counterbore in the cylinder block. The cylinder
liners have a lip (Figure 1, Item 2), which rests on the ridge. The seals of the coolant jacket are located in the upper
regions and middle regions of the cylinder liners. The lower barrier uses a D-ring seal (Figure 1, Item 3) that is
located above the seating surface of the cylinder liner. The upper barrier is the head gasket, which is above the
coolant jacket.
The cylinder block has seven main bearings in order to support the crankshaft. The main bearing caps are
fastened to the cylinder block with two bolts per cap.
Figure 1. Cylinder Block.
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