Cylinder Block - TM-5-4320-258-340058

TM 5-4320-258-34

Figure 4-21. Checking for insufficient timing gear

clearance.

(5) If gear clearance is too great or too

small, the gears must be replaced. Replace the gears

Figure 4-20. Timing gears showing alinement marks.

only in sets. Gear sets are available in standard size

(marked S), 0.002 and 0.004 inch undersize (marked U),

(3) Check camshaft, end play with a dial

and 0.002 and 0.004 inch oversize (marked O). Install a

indicator. If end play is .not between 0.005 and 0.009

gear set marked the same as the set removed. Check

inch, remove the camshaft timing gear and, replace the

the clearance as directed in (4) above. If clearance is

thrust plate (19, fig. 4-3).

too great, install the next smaller size gear set. If

(4) Check the clearance between the

clearance is insufficient, install the next larger size set.

camshaft and crankshaft gears as follows:

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

(a) Force the teeth of the gears apart

(7) Install the valves and valve tappets

with a screwdriver. Attempt to insert a 0.002-inch feeler

gage into the gap between the gears. If the gage will

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

enter, the clearance is excessive.

4-13. Cylinder Block

(b) If the gage will not enter, place a

a. Removal and Disassembly.

With the

finger at the junction of the two gears as shown in figure

engine mounted on an engine overhaul stand, proceed

4-21 and tap the camshaft gear with a hammer. If

as follows:

vibrations can be felt in the large gear, the clearance is

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

sufficient.

4-25