Engines - Jeep 1979 CJ-5 Technical & Service Manual

1 1 - 1
E N G I N E S
S E C T I O N I N D E X
Slx-Cyllndir Engine
Eight-Cylinder Engine
Page
1B-1
1B-36
Page
Tools 1 B - 7 3
SIX-CYLINDER ENGINE
Page
Page
Camshaft and Bearings
1B-8 Intake Manifold Replacement IB-15
Connecting Rods
1B-22 Lubrication System 1 B - 1 7
Connecting Rod and Piste* Assembly 1B-22
Oil Filter 1B-19
Crankshaft 1B-28
Oil Pan
1B-21
Cylinder Block 1B-32 Oil Pump I B 19
Cylinder Bore Reconditioning
1B-33
Pistons
1B-25
Cylinder Head and Cover
1 B - 1 6 Rocker Arm Assembly
1B-5
Engine Holding Fixture
1B-3 Short Engine Assembly 1B-2
Engine Installation 1B-4
Specifications
1B-34
Engine Mounting
1B-3
Timing Case Cover
1B-12
Engine Removal 1B-4
Timing Chain
1 B - 1 3
Exhaust Manifold Replacement iB-15
Valves
1B-5
General 1B-1
Valve Train 1B-4
Hydraulic Valve Tappets I B - 1 0
Vibration Damper
1B-31
Intake and Exhaust Manifolds 1 B - 1 4
Vibration Damper
m m
G E N E i A L Identification
The 258 CID (4.2 liter) is a six-cylinder, in-line, over-
head valve engine (fig. 1B-1 and 1B-2) which operates
only on no-lead gasoline. Cylinders are numbered from
front to rear. Firing order is 1-5-3-6-2-4, Crankshaft
rotation is clockwise, viewed from the front. The crank-
shaft is supported by seven two-piece bearings. The
camshaft is supported by four one-piece, line bored
bearings.
The six-cylinder engine features a quench-head de-
sign. The combustion chamber shape, both in the head
and in the piston crown, compresses the combustion
mixture closer to the spark plug. In most applications,
this permits the use of more ignition timing advance for
better fuel economy.
Build Date Code
The engine Build Date Code is located on a machined
surface on the right side of the block between the No. 2
and No. 3 cylinders (fig. 1B-3).
The numbers of the code identify the year, month and
day that the engine was built.
The code letter identifies the cubic inch displacement,
carburetor type and compression ratio. The letters are
decoded as follows:
The example code shown in the Engine Build Date
Code chart identifies a 258 CID (4.2 liter) with 2V carbu-
retor and 8.00:1 compression ratio built on March 18,
1979.