CRANKCASE BREATHER (F10000RG-2) See figure 549.

TM5-4110-234-14

TO 40R7-5-7-1

5-41.

CRANKCASE BREATHER (F10000RG-2) See figure 549.

Figure 5-49. Crankcase Breather F10000RG-2

a. The crankcase breather maintains a partial vacuum in the crankcase during operation to control oil loss and

ventilate the crankcase.

b. To disassemble, remove the rubber cap from the crankcase tube and pry the valve out of the cap. Wash the

valve in suitable solvent at regular intervals and, if defective, replace it. Also, pull the baffle out of the breather tube and

clean it. Be sure the baffle material does not come apart and work into the manifold. Install the valve with the perforated

disc toward the engine.

5-42.

ENGINE BLOCK (F10000RG-2) See figure 5-38.

a. Inspection.

(1) Make a thorough check for cracks. Minute cracks may be detected by coating the suspected area with a

mixture of 25 percent kerosene and 75 percent light motor oil. Wipe the part dry and immediately apply a coating of zinc

oxide (white lead) dissolved in wood alcohol. If cracks are present, the white coating will become discolored at the

defective area.

(2)

Inspect the cylinder bore for scoring. Check the Welsh plugs for a tight, even fit and the fins for breakage.

(3) Check the cylinder bore for taper, out of round and wear with a cylinder bore gage, telescope gage or inside

micrometer (fig. 5-50). These measurements should be taken at four places - two at the top and two at the bottom of

piston ring travel.

(4)

Record measurements taken lengthwise at the top and bottom of the piston travel as follows:

(a) Lengthwise of the block, measure and record as "A" the diameter of the cylinder at the top of the cylinder

where the greatest ring wear occurs.

5-63