DETROIT DIESEL 53
1.1 Cylinder Block
4. Check the main bearing bores as follows:
plates and drain the water jacket. Then remove the
liners and seaI rings and blow out all of the passages
a. Check the bore diameters with the main bearing
in the block with compressed air.
caps in their original positions. Lubricate the bolt
threads and bolt head contact areas with a small
6. Dry the cylinder Iiners with compressed air and coat
quantity of International Compound No. 2, or
them with oil to prevent rust.
equivalent. Then install and tighten the bolts to
the specified torque. When making this check, do
not install the main bearing cap stabilizers. The
Inspect Cylinder Block
specified bore diameter is 3.251 " to 3.252 " (In-
Line engine).
After cleaning and pressure testing, inspect the
If the bores do not fall within these
cylinder block.
limits, the cylinder block must be rejected.
1. Check the block bores as follows:
CAUTION: Main bearing cap bolts are espe-
cially designed for this purpose and must not be
a. Make sure the seal ring grooves (Fig. 11) are
replaced by ordinary bolts. Effective with
thoroughly clean. Then inspect the grooves and
engine serial numbers 6D-27030 and 8D-1155,
lands for evidence of pitting and erosion. Two
a new hexagon head bolt and hardened steel
grooves are provided above the air inlet ports of
washer are being used in place of the former
each cylinder bore in the current block. The single
12-point flange type main bearing cap bolt.
groove formerly below the air inlet ports has been
eliminated. However, a cylinder liner seal ring is
NOTE: Bearing caps are numbered to corre-
required in the upper groove only. The lower
spond with their respective positions in the
groove (on the current block) is provided for the
cylinder block. It is imperative that the bearing
seal ring if inspection reveals extensive pitting or
caps are reinstalled in their original positions to
erosion along the upper land or inner surface of
maintain the main bearing bore alignment. The
the upper groove. If both grooves are eroded to
number of the front main bearing cap is also
the extent that sealing is affected, then the block
stamped on the face of the oil pan mounting
must be replaced.
flange of the cylinder block, adjacent to its
permanent location in the engine as established
b. Measure the entire bore of each cylinder with
at the time of manufacture. The No. 1 main
cylinder bore gage J 5347 (Fig. 12) which has a
bearing cap is always located at the end
dial indicator calibrated in .0001 " increments.
opposite the flywheel end of the cylinder block
Use dial bore gage setting tool J 23059 to preset
(Fig. 14).
the cylinder bore gage to zero. Measure- each
block bore at the positions indicated in Fig. 13,
b. Finished and unfinished main bearing caps are
on axis 90o apart. If the diameter does not exceed
available for replacing broken or damaged caps.
4.5235 " at position "A", 4.4900 " at position "B"
When fitting a finished replacement bearing cap,
(and a sealing problem hasn t occured), or
it may be necessary to try several caps before one
4.3595 " at position "C" and "D", then the block
will be found to provide the correct bore diameter
may be reused. Also, the taper and out of round
and bore alignment. If a replacement bearing cap
must not exceed .0015 "
is installed, be sure to stamp the correct bearing
position number on the cap.
2. Check the top of the block for flatness with an
accurate straight edge and a feeler gage. The top
NOTE: Use the unfinished bearing caps for the
surface must not vary more than 003 " transversely
front and intermediate bearing positions. The
and not over
.006 " (3-53
finished bearing caps, machined for the
engine)
longitudinally.
crankshaft thrust washers, are to be used in the
rear bearing position.
3. Make sure the cylinder liner counterbores in the
c. Main bearing bores are line-bored with the
block are clean and free of dirt. Then check the depth.
The depth must be .300 " to .302 " and must not vary
bearing caps in place and thus are in longitudinal
more than .0015 " throughout the entire circumfer-
alignment. Bearing bores may be considered
p r o p e r l y aligned with one another if the
ence. The counterbored surfaces must be smooth and
square with the cylinder bore within .001 " total
crankshaft can be rotated freely by hand after
indicator reading. There must not be over .001 "
new bearing shells have been installed and
lubricated and the bearing caps have been
difference between any two adjacent cylinder counter-
secured in place and the bolts tightened to the
bores, when measured along the cylinder longitudinal
specified torque. If a main bearing bore is more
centerline of the cylinder block.
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