CHAPTER 8. ASSEMBLY OF ENGINE

CHAPTER 8

ASSEMBLY OF ENGINE

Section I. GENERAL

and excess torque may easily overstress the

253. CLEANLINESS

stud. Do not exceed torque specified.

The engine is a precision product and extreme

d. Locking Devices. Many of the cap screws

care and cleanliness must be exercised in all

used in this engine are designed with a nylon

phases of assembly operations to insure satis-

insert in the shank. Cap screws of this type need

factory engine performance. Dirt and dust, even

no additional locking device. Most, but not all,

in minute quantities, are abrasive. After clean-

nuts and cap screws require either lock washers,

ing, and just before assembly, coat all bearings

cotter pins, or locking wire. Pay particular at-

and moving parts with engine oil (OE-10). This

tention during engine assembly to use the locking

will insure sufficient lubrication until the engine

device indicated. Many engine failures have been

is started.

traced to neglect of this simple precaution.

254. GENERAL ASSEMBLY INSTRUCTIONS

a. Gaskets. Use new gaskets, preformed

255. INSTALLATION INSTRUCTIONS

packings, and annular copper gaskets when as-

a. General. Usually the subassemblies are

sembling the engine. An engine overhaul gasket

and preformed packing set -5702654, consisting

installed on the engine by reversing the removal

of all necessary gaskets, preformed packings,

procedure. When instructions under removal call

and oil seals is available for engine overhaul.

for locking wire to be cut, install new locking

wire in the specified location. When instructions

b. Kits and Sets. Several of the components

under removal call for removing and discarding

of the engine are available in kits or sets.

of a gasket, install a new gasket. All instruc-

Whenever a kit or set is used for parts re-

tions will be a step-by-step, or figure-by-fig-

ure, reversal of the removal sequence. For

placement, all components of the kit should be

installed.

example, using the letters C, B, and A on the

illustration in this order is reversing the re-

c. Attaching Parts. All bolts and nuts should

moval instructions A, B, and C. This method of

reverse procedure will be used throughout this

be tightened in accordance with the specifica-

tions listed in paragraph 299. When other torque

chapter unless otherwise indicated by additional

values apply, they will be noted in the text. Tor-

instructions in the following paragraphs.

que wrenches with indicating scales are pro-

vided for tightening to specified limits (par.

b. Engine Assembly Reference Table. An en-

299). Readings on the torque wrench scales are

gine components assembly guide (table V) is

worthless unless the wrenches are properly

provided as a reference to-the engine assembly

used. It must be understood that it is not the

procedures contained in this chapter. The table

force required to turn the nut that is important,

lists the main components, assemblies, and

but the resultant pull on the stud. Therefore,

subassemblies of the engine and the applicable

resistance of the nut to turning must be reduced

paragraph and figure references which contain

to a minimum. Threads must be undamaged

the assembly instructions.

and clean, and lubricated with antiseize com-

pound (MIL-13881) to reduce friction.

c. Parts Identification. Callouts, referenced

to the exploded view illustrations, will be used

to point out related parts involved in assembly

Note. When using a torque wrench, the final

operations. Callouts not mentioned in the in-

reading must be taken while the nut is turning.

structions are related to subsequent installation

When torque reading is close to that specified

procedures or are used as references to other

when the wrench is at the end of its swing, back

pertinent operations in this technical manual.

off slightly, and change wrench position; then

pull to the desired reading while the nut is

Note. Parts mentioned in the instructions

turning. To start a partially tightened nut will

will called out separately on the illustration

requite a much higher torque than that required

only when required to further clarify the in-

to keep a nut turning. The ratio of pounds tor-

structions.

que to pounds pull on a stud is not an even ratio

296