Manifolds

TM 10-3930-630-12

(a) Remove engine oil filler cap (fig. 3-

the engine and contains recesses which form the top f

2). Place a suitable container beneath engine. Remove

the cylinders. It also contains passages for engine

drain plug from oil pan and drain oil from engine

coolant flow.

The engine coolant outlet elbow is

(b) Install drain plug and fill crankcase

mounted on the cylinder head and contains the

with correct grade of oil. Refer to current Lubrication

thermostat. Spark plugs and distributor are mounted on

Order for quantity and grade.

the top of the cylinder head

b. Removal.

(3) When the crankcase oil is changed the oil

filter should be changed as follows.

(1) Open side panels and lift seat into upright

(a) Drain oil from engine as described

position.

above.

(2) Refer to paragraphs 4-58 and 4-54 and

(b) Unscrew oil filter (fig. 3-2) from filter

remove distributor and spark plugs from cylinder head.

base. Discard oil filter.

(3) Refer to paragraph 4-50 and remove

coolant temperature sending unit from cylinder head

lint-free cloth.

(4) Refer to paragraph 4-70 and remove

(d) Spread a light coat of clean engine oil

coolant outlet elbow and thermostat from cylinder head

on gasket surface of new filter. Install filter on filter

and disconnect coolant bypass hose.

base and hand tighten only

(5) Mark locations of screws (4, fig. 460).

(e) Fill crankcase with oil as described in

Remove screws (4 and 5) and carefully remove cylinder

(2) above.

head from engine.

(4) Close side panels and lower seat.

(6) Remove gasket (10) from engine block

(7) Remove remaining screws, studs and pipe

4-81.

Manifolds

plugs from cylinder head.

(8) Wipe all exposed internal engine areas

Inspection.

with a clean dry cloth to remove all engine coolant.

(1) Open left side panel

Cover exposed areas with a protective cover such as a

(2) Inspect manifold for cracks and damage

plastic sheet.

c. Inspection and Service.

and for evidence of leaks.

(3) Check manifold mounting screws and nuts

(1) Use a scraper and wire brush and remove

Tighten if necessary.

all carbon from combustion areas.

b. Removal.

(2) Clean the cylinder head with cleaning

compound, solvent (Fed. Spec. P-D480) and dry

(1) Refer to paragraph 4-58 and remove

thoroughly with compressed air.

carburetor and governor from manifold.

(3) Check gasket contact surfaces to be sure

(2) Refer to paragraph 4-62 and disconnect

they are clean, smooth and flat.

crankcase ventilation hose and remove ventilation valve

(4) Inspect cylinder head for cracks, holes,

and elbow from manifold.

warpage and other damage.

(3) Refer to paragraph 4-72 and disconnect

(5) Check cylinder head for flatness shown in

exhaust pipe from top of manifold.

figures 4-61 and 4-62.

(4) Remove screws (6, fig. 4-49) and washers

(a) Use a straightedge and feeler gage as

(7) Remove nuts (8) and washers (9).

shown in the illustrations to check flatness

(5) Remove manifold (11) and gasket (12)

(b) Maximum out-of-flatness should not

from cylinder block.

c. Installation.

exceed 0.000765 inch (0.019 mm) per inch of width or

length. On a cylinder head 16 inches (40.6 mm) long,

(1) Clean carbon deposits from manifold and

maximum lengthwise out-of-flatness is 0.012 inch (0.305

gasket surface on cylinder block with a wire brush.

mm). Any out-of-flatness should vary gradually and

(2) Install a new gasket (12, fig. 449) on

uniformly from end to end and side to side. Localized

cylinder block and install manifold (11).

depressions or high spots should not exceed 0.008 inch

(3) Secure manifold to engine with screw (6)

(0.076 mm).

washer (7), nuts (8) and washers (9). Tighten nuts to a

torque of 25 to 30 pound-feet (33.7 to 40.6 N.m).

to direct and general support maintenance. (d)

(4) Refer to paragraph 4-72 and connect

Replace unserviceable cylinder head.

exhaust pipe to top of manifold.

d. Installation.

(5) Refer to paragraph 4-62 and install ventila-

(1) Install stud (8, fig. 4-60), screw (8) and

tion valve and elbow and connect hose to manifold

washer (9), screw (1) and washer (2), and pipe plugs (7)

(6) Refer to paragraph 4-58 and install

in cylinder head.

carburetor and governor on manifold.

(2) Install a new gasket (10) on engine block

(7) Close left side panel

and install cylinder head.

4-82. Cylinder Head

(3) Install screws (4) in locations marked at

a. General. The cylinder head encloses the top of

removal. Install screws (5) in remaining holes. Torque

screws in the sequence shown in fig. 4-63.

4-71