The cylinder block (Fig. 1) serves as the main structural part of the engine. Transverse webs provide rigidity
and strength, and ensure alignment of the block bores and bearings under load. Cylinder blocks for the two-,
three-, and four-cylinder in-line engines are identical in design and dimensions except for length.
The block is bored to receive replaceable wet-type cylinder liners. On the in-line cast iron cylinder blocks, a
water jacket surrounds the upper half of each cylinder liner. The water jacket and air box are sealed off by a
seal ring compressed between the liner and a groove in the block (Fig. 2).
The current cylinder blocks have an additional seal ring groove approximately 1/8
inch below the original top groove. The lower seal ring groove in the current
cylinder block has been eliminated. All turbocharged engines use a seal ring in
both upper grooves.
An air box surrounding the lower half of the cylinder liners conducts the air from the blower to the air inlet ports
in the cylinder liners. An opening in the side of the ,block opposite the blower on ,the in-line engines provides
access to the air box and permits inspection of the pistons and compression rings through the air inlet ports in
the cylinder liners.
The camshaft and balance shaft bores are located on opposite sides near the top of the in-line engine block.
The upper halves of the main bearing supports are cast integral with the block.
Figure 1. Cylinder Block