Cylinder Block, Cleaning, Inspection and Rpair

TM 10-3930-630-34

(3) Hone cylinders with a suitable honing tool

1-40.

Cylinder Block, Cleaning, Inspection and

to a good cross hatch honed pattern.

Repair

(4) Insert hone into cylinder and expand to

a. Clean all oil passages with cleaning solvent

cylinder wall with a slight tension as shown in figure 11-

Fed. Spec. P-D-680) and blow out with compressed

43.

air.

b. Clean valve compartment and cylinders

thoroughly.

Remove carbon deposits from top of

crankcase and cylinder walls. Do not nick or scratch

surfaces.

c. Inspect crankcase for cracks in the exhaust

salve area and bearing flanges.

d. Check cylinders with a micrometer as follows:

(1) Measure original bore diameter above ring

travel with a micrometer as shown on figure 11-42, at 45

degree intervals.

TA067483

Figure 11-43. Honing cylinders

(5) Use a clean brush and wet cylinder walls

and stones with kerosene. Use a hand drill and surface

one cylinder with an up and down motion. Apply

kerosene as needed occasionally while honing.

Increase tension until a good finish is obtained. A

smooth finish of 10 to 15 micro inches is desired.

(6) Remove hone. Clean bores with a clean

rag soaked in oil (OE/HDO). Wipe bore clean with a

clean dry cloth. Measure bores with a micrometer to

see that they are within tolerances specified above.

11-41. Cylinder Block, Reassembly and Installation

a. Reassembly. Reassemble the cylinder block in

reverse numerical sequence as illustrated in figure

11-41.

b. Installation.

(1) Refer to paragraph 11-26 and install the

camshaft.

Figure 11-42. Measuring cylinder bore diameter.

(2) Refer to paragraph 11-37 and install the

crankshaft and main bearings.

(2) Measure the bore diameter below the top

(3) Refer to para, graph 11-33 and install the

of ring travel in the same manner.

flywheel housing.

(3) If the difference between the two

(4) Refer to paragraph 11-30 and install the

measurements does not exceed 0.008 inch (0.202 mm),

flywheel.

the engine does not have to be rebored.

(5) Refer to paragraph 11-23 and install the

(4) If the difference exceeds 0.008 inch,

gear cover and fan drive.

rebore the cylinder.

(6) Refer to paragraph 11-19 and install the

e. Repair cylinder as follows:

piston and connecting rods.

(1) Ridge ream the cylinder to remove the

(7) Refer to paragraph 11-15 and install the oil

unworn area at the top.

pressure relief valve.

(2) Rebore cylinder diameter to a maximum of

3.1268 inches (79.42-mm). This diameter will allow a

0.002 inch (0.050-mm) excess to allow for honing the

cylinder walls.

11-29