TM 9-4940-421-14
bores as necessary.
(g) Apply a thin coat of grease to the two
(3) Use a wire brush, compressed air, and cleaning
gaskets (28). Position the thicker gaskets (27) around
solvent to clean the cooling fins of the cylinder blocks.
the rear opening of the crankcase and the gasket on the
Inspect the cylinder blocks for cracks, breaks, or
main bearing plate.
damaged cooling fins. Replace defective cylinder block.
(h) Install the bearing plate and shims on the
(4) Inspect the manifold mounting studs, cylinder
crankcase. Secure them with the six capscrews and
block mounting studs, mounting hardware. Tighten
lockwashers. Tighten capscrews to 25-30 lbs. ft. torque.
any loose mounting studs. Replace any defective hard-
(i) Use a dial indicator and set its contact point
ware.
against the end of the crankshaft. With a screwdriver
pry the crankshaft back and forth, being careful not to
(5) Examine the threaded cylinder head mounting
holes. Repair any holes that have bad threads.
damage the connecting rod journals. If the end play of
the crankshaft exceeds 0.005 inch, remove shims to ad-
(6) Replace the cylinder block gaskets.
just. Add shims if there is not at least 0.002 inch end
d. Installation of the Cylinder Block.
play.
(1) Position a new gasket (1, fig 6-6) over the studs
(j) Install the connecting rods and pistons (para
of the crankcase. Install the appropriate cylinder block
( 1 2 ) and secure it with the six lockwashers (22) and
(k) Install the idler and camshaft gears (para
nuts (21). Tighten the nuts to 62-78 lbs. ft. torque.
(2) Install the pistons and connecting rods (para
(1) Install the gear cover (para 6-15a (2)).
(m) Install the fuel pump (para 6-4).
(3) Install the valves (para 6-12).
(n) Install the cylinder heads and valves (para
e. Disassembly of the Crankcase.
(1) Remove the timing gears (para 6-16).
(2) Remove the crankshaft (para 6-18).
(3) Remove the camshaft (para 6-18).
a. General.
(1) Crankcase. The crankcase is a one-piece cast-
(4) Remove the cylinder blocks (para 6-19).
ing machined at the top and fitted with studs to mount
(5) Remove the oil filler tube.
the two cylinder blocks. The camshaft bores are honed,
f. Cleaning and Inspection of the Crankcase.
and serve as bearing surfaces for the camshaft.
(1) Clean the crankcase with a wire brush and
(2) Cylinder Blocks. The cylinder blinks are cast
cleaning solvent and dry thoroughly (app D).
in pairs and are provided with cooling fins. The valve
(2) Examine the oil filler tube for corrosion, bends,
stem bores are machined in each of the blocks.
or dents. Repair or replace the oil filler tube as neces-
b. Removal of Cylinder Block.
sary.
(1) Remove the valves (para 6-12).
(3) Examine the crankshaft bores. Replace a
(2) Remove the connecting rod and pistons (para
defective crankcase.
(4) Examine the crankcase for cracks or breaks.
(3) Remove the six nuts (21, fig 6-6) and lock-
Replace a defective crankcase.
washers (22) that secure each cylinder block (12) to the
crankcase. Remove the cylinder blocks and gaskets (1).
g. Reassembly of the Crankcase.
Tag them so that they will be reinstalled on the same
(1) Chill the oil filler tube with dry ice and install
in the crankcase.
side of the crankcase from which they are removed.
(2) Install the camshaft (para 6-18).
c. Cleaning and Inspection of Cylinder Block.
(3) Install the crankshaft (para 6-18).
(1) Clean, inspect and repair the cylinder bores as
necessary.
(4) Install the timing gears (para 6-16).
(2) Clean, inspect and repair the valve seats and
(5) Install the cylinder blocks (para 6-19).
