TM 5-3895-359-14&P
the stepped pins, rebore the dowel holes
is installed, be sure to stamp the correct bearing position
in the bearing cap with a No. 11 (.1910
number on the cap.
") or No. 12 (.1890 ") drill. After
pressing the pins into the bearing cap,
NOTE: Use the unfinished bearing caps
remove all burrs from the base of the
for the front and intermediate bearing
dowel pins to ensure proper seating of
positions. The finished bearing caps,
the thrust washers.
machined for the crankshaft thrust
washers, are to be used in the rear
10. Examine the tapped bolt holes for the cylinder head
bearing position.
or main bearing cap bolts and, if the threads are
damaged, "clean-up" the threads or install a helical
c. Main bearing bores are line-bored with the
thread insert. The tapped holes may be tapped with a
bearing caps in place and thus are in
5/8 "-II UNC3B tap. All cylinder head bolt or stud holes
longitudinal alignment. Bearing bores may be
must have the threads extending 1.84 " below the block
considered properly aligned with one another if
surface.
the crankshaft can be rotated freely by hand
NOTE:
The
current
service
after new bearing shells have been installed and
replacement cast iron cylinder blocks
lubricated and the bearing caps have been
use a special cylinder head bolt in all
secured in place and the bolts tightened as
positions.
specified on Page 10-2-62. If a main bearing
bore is more than .001" out of alignment, the
11. Check the drive pins (which plug the vertical oil
block must be linebored or scrapped.
galleries) in the corners of the block to be sure they are
Misalignment may be caused by a broken
flush with or below the top surface of the block.
crankshaft, excessive heat or other damage.
d. If the main bearing bores are not in alignment
12. Check the remaining cylinder block surfaces and
when a replacement bearing cap is used, the
threaded holes. Check all of the mating surfaces, or
block must be line-bored. Install the bearing
mounting pads, for flatness, nicks and burrs. The
caps in their original positions and tighten the
flatness of the blower mounting pad must not vary more
bolts to 165-175 lb-ft (224-238 Nm) torque.
than .004 ". Clean-up damaged threads in tapped holes
Line-bore the block, but do not remove more
with a tap or install helical thread inserts, if necessary.
than .001" stock. After boring, all bores must be
within the specified limits of 3.812" to 3.813".
13. After inspection, if the cylinder block is not to be
used immediately, spray the machined surfaces with
8. Refer to the Cylinder Block Plugging Charts at the
engine oil. If the block is to be stored for an extended
end of this section and install the necessary plugs and
period of time, spray or dip it in a polar type rust
dowels.
preventive such as Valvoline Oil Company's "Tectyl
502-C", or equivalent. Castings free of grease or oil will
9. Replace loose or damaged dowel pins. The dowels
rust when exposed to the atmosphere.
at the ends of the cylinder block must extend .625 " from
the face of the block.
Assemble and Install Engine
The dowels used to retain the crankshaft thrust washers
After the cylinder block has been cleaned and inspected,
on the rear main bearing cap must extend .110 " to .120
assemble the engine as follows:
" from the surface of the bearing cap.
NOTE: Before a reconditioned or new
NOTE:
A stepped dowel pin is
service replacement cylinder block is
available to replace loose pins in the
used, steam clean
rear main bearing cap. Before installing
10-2-13
