Camshaft - TM-5-4320-258-340057

TM 5-4320-258-34

Cleaning and Inspection.

(1) Clean all parts with cleaning solvent

(FED. Spec. P-D-680); dry thoroughly.

(2) Inspect the camshaft for cracks, worn or

scored cams worn or scored bearing surfaces, chipped,

cracked, or broken gear teeth, and clogged oil

passages. Refer to table 4-1 for wear limits.

Replace a damaged camshaft.

(3) Inspect the thrust washer for scoring

and wear. Replace the thrust washer if any signs of

wear are evident.

(4) Inspect the cam gear for cracked,

chipped, or broken gear teeth, damaged shaft bore, or

worn thrust surface. The cam gear and the mating gear

on the crankshaft must be replaced as a pair. Do not

attempt to replace these gears singly.

(5) Inspect the plug (33, fig. 4-22) in the

cylinder block. Replace if any leaking is evident from

the circumference of the plug.

(6) Inspect the camshaft bearings in the

Figure 4-19. Checking bearing clearance with shim

cylinder block for scoring or visible damage; replace

stock.

damaged bearings if necessary. Check the camshaft-to-

bearing clearance and, if necessary, replace bearings as

follows:

with the screws and lock washers. Tighten the screws to

85 to 95 foot-pounds torque.

Caution: Do not insert the camshaft too far

(d) Try to turn the crankshaft by hand.

into the block.

If the camshaft bumps the

If the crankshaft will not turn or a very definite drag is

expansion plug on the drive end of the engine, an

felt, bearing-to-bearing journal clearance is within

oil leak could result.

tolerance. Remove the shim stock and reinstall the

bearing caps.

(a) Temporarily insert the camshaft

(10) After all main bearings have been

(20, fig. 4-3) in the block. Check the clearance between

installed, use a dial indicator to check crankshaft end

the camshaft bearing journals and camshaft bearings

play. If end play is not between 0.003 and 0.008 inch,

(21, 22, 23, and 24) with feeler stock cut in strips 1/4

replace the thrust plate (24) which controls the shaft end

inch wide. Dress the feeler stock with a stone to

play..

eliminate burrs or feathered edges. Clearance between

(11) Install the pistons and connecting rods

bearings and journals must be between 0.002 and 0.004

(para 4-10c).

inch.

(12) Install the flywheel housing and

(b) If clearance exceeds tolerances,

flywheel (para 4-9c).

remove the camshaft and remove the camshaft

(13) Install the gear cover (para 4-8c).

bearings. New bearings are pre-reamed. Install new

(14) Install the oil pan (para 4-6c) and oil

bearings, taking care to aline the oil holes with the

pump (para 4-7c).

passages in the block. Use caution to prevent damage

(15) Install the cylinder head (para 4-3c).

to the bearings during installation.

4-12. Camshaft

c. Installation.

a. Removal. With the engine removed from

(1) Lubricate the camshaft bearings with

the pump assembly and mounted on an engine stand,

engine oil and install the camshaft in the block. Position

proceed as follows:

the thrust plate (19, fig. 4-3) on the camshaft; secure

(1) Remove the cylinder head (para 4-3a).

with two cap screws (17) and lock washers (18).

(2) Remove the valves and valve tappets

(para 4-4b).

Caution: When installing the camshaft gear,

(3) Remove the gear cover (para 4-8a).

do not attempt to seat the gear by tightening the

(4) Remove the nut (14, fig. 4-3) from the

retaining nut. This may break threads on the

camshaft (20) and pull the gear (15) from the cam shaft.

camshaft, requiring camshaft replacement.

(5) Remove the two cap screws (17) and

lock washers (18) that secure the thrust plate (19) to the

(2) Hold the camshaft toward the front of

block; remove the thrust plate.

the engine with a bar inserted into the fuel pump hole.

(6) Pull the camshaft (20) from the block.

Aline the timing marks on the camshaft and crankshaft

gears (fig. 4-20) and drive the gear (15, fig. 4-3) onto

the camshaft.

4-24