Figure 3-33. crankshaft gear and pulley.

(2) Heat crankshaft timing drive gear (3) in

and camshaft gears and mesh gears. It may be

boiling oil for at least 15 minutes to expand gear ID.

necessary to tap gear with a wooden block and hammer

(3)

Pick up gear with tongs or pliers and

to seat it over key and against crankshaft shoulder.

slide onto crankshaft. Aline "C" marks on crankshaft

1 Locknut

2 Pulley

3 Gear

4 Crankshaft

5 Key, gear

6 Key, pulley

Figure 3-33. crankshaft gear and pulley.

grooves in pin boss of piston. Pins are full-floating, but

normal movement is between pin and bushing in the

connecting rod.

(2) Connecting rods. Each connecting rod,

made of drop-forged, heat-treated steel, is forged to an

"I" section with closed hub at upper end and integral cap

at lower end and is dynamically and electronically

balanced. Connecting rod bearings are replaceable

without machining.

Each half of bearing shell is

prevented from radial movement by a tang at parting line

on one side of bearing shell. Bearing shells are held in

place by a cap which is attached to the connecting rod

with two special capscrews and castellated nuts. Upper

end of connecting rod contains a bushing which is

pressure lubricated.

b. Removal. Connecting rods and pistons may be

Figure 3-34. Removing crankshaft.

replaced without removing engine from truck. (If engine

has already been removed from truck, disregard (1), (2),

3-22. Pistons and Connecting Rods

and (3) below).

a. Description.

(1) Remove cylinder head (para 3-20).

(1) Pistons.

The

precision-machined,

(2) Remove steering axle assembly (para 2-

balanced, cast aluminum alloy, cam ground, and tip-

14).

plated pistons are fitted with two compression and two oil

control rings, all located above piston pin. Behind oil

control ring, holes drilled through piston allow excess oil

in groove to return to crankcase. Piston pins are full-

floating type held in piston by two retainer rings fitted into

3-41