Jeep XJ. Manual — part 283
ENGINE
TABLE OF CONTENTS
page
page
2.5L ENGINE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
4.0L ENGINE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
2.5L ENGINE
TABLE OF CONTENTS
page
page
DESCRIPTION AND OPERATION
ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
LUBRICATION SYSTEM . . . . . . . . . . . . . . . . . . . . . 2
CYLINDER BLOCK. . . . . . . . . . . . . . . . . . . . . . . . . 5
CYLINDER HEAD. . . . . . . . . . . . . . . . . . . . . . . . . . 5
CRANKSHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
PISTON AND CONNECTING ROD . . . . . . . . . . . . . 6
CAMSHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
ROCKER ARM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
VALVE SPRING . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
CYLINDER HEAD COVER . . . . . . . . . . . . . . . . . . . 7
HYDRAULIC TAPPET. . . . . . . . . . . . . . . . . . . . . . . 7
VALVE GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
OIL PAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
VALVE STEM SEAL . . . . . . . . . . . . . . . . . . . . . . . . 8
INTAKE MANIFOLD . . . . . . . . . . . . . . . . . . . . . . . . 8
EXHAUST MANIFOLD . . . . . . . . . . . . . . . . . . . . . . 8
DIAGNOSIS AND TESTING
ENGINE DIAGNOSIS—INTRODUCTION. . . . . . . . . 8
SERVICE DIAGNOSIS—PERFORMANCE . . . . . . . 9
SERVICE DIAGNOSIS—MECHANICAL. . . . . . . . . 10
INTAKE MANIFOLD LEAKAGE DIAGNOSIS . . . . . 13
CYLINDER COMPRESSION PRESSURE TEST . . 13
ENGINE CYLINDER HEAD GASKET FAILURE
DIAGNOSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
LEAKAGE TEST . . . . . . . . . . . . . . . . . . . . . . . . 13
ENGINE OIL LEAK INSPECTION . . . . . . . . . . . . . 14
ENGINE OIL PRESSURE . . . . . . . . . . . . . . . . . . . 15
SERVICE PROCEDURES
VALVE TIMING . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
VALVE, GUIDE AND SEAL . . . . . . . . . . . . . . . . . . 15
PISTON—FITTING . . . . . . . . . . . . . . . . . . . . . . . . 17
PISTON RING—FITTING . . . . . . . . . . . . . . . . . . . 18
CONNECTING ROD BEARINGS—FITTING . . . . . 21
FITTING CRANKSHAFT MAIN BEARINGS . . . . . . 23
FORM-IN-PLACE GASKETS. . . . . . . . . . . . . . . . . 25
ENGINE PERFORMANCE . . . . . . . . . . . . . . . . . . 26
HONING CYLINDER BORES . . . . . . . . . . . . . . . . 26
REMOVAL AND INSTALLATION
ENGINE MOUNTS—FRONT. . . . . . . . . . . . . . . . . 29
ENGINE MOUNT—REAR . . . . . . . . . . . . . . . . . . . 30
ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
INTAKE MANIFOLD . . . . . . . . . . . . . . . . . . . . . . . 33
EXHAUST MANIFOLD . . . . . . . . . . . . . . . . . . . . . 35
CYLINDER HEAD COVER . . . . . . . . . . . . . . . . . . 35
ROCKER ARMS AND PUSH RODS . . . . . . . . . . . 36
VALVE SPRING AND SEAL . . . . . . . . . . . . . . . . . 37
CYLINDER HEAD. . . . . . . . . . . . . . . . . . . . . . . . . 38
CYLINDER HEAD. . . . . . . . . . . . . . . . . . . . . . . . . 40
HYDRAULIC TAPPETS. . . . . . . . . . . . . . . . . . . . . 40
VIBRATION DAMPER . . . . . . . . . . . . . . . . . . . . . . 41
TIMING CASE COVER OIL SEAL . . . . . . . . . . . . . 41
TIMING CASE COVER . . . . . . . . . . . . . . . . . . . . . 42
TIMING CHAIN AND SPROCKETS . . . . . . . . . . . . 43
CAMSHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
CAMSHAFT PIN REPLACEMENT . . . . . . . . . . . . . 45
CAMSHAFT BEARINGS . . . . . . . . . . . . . . . . . . . . 47
CRANKSHAFT MAIN BEARINGS . . . . . . . . . . . . . 47
OIL PAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
OIL PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
PISTON AND CONNECTING ROD . . . . . . . . . . . . 51
REAR MAIN OIL SEAL . . . . . . . . . . . . . . . . . . . . . 52
DISASSEMBLY AND ASSEMBLY
CYLINDER BLOCK. . . . . . . . . . . . . . . . . . . . . . . . 53
CLEANING AND INSPECTION
ROCKER ARMS AND PUSH RODS . . . . . . . . . . . 53
ENGINE CYLINDER HEAD . . . . . . . . . . . . . . . . . . 54
CYLINDER BLOCK. . . . . . . . . . . . . . . . . . . . . . . . 54
SPECIFICATIONS
ENGINE SPECIFICATIONS. . . . . . . . . . . . . . . . . . 55
SPECIFICATIONS—TORQUE . . . . . . . . . . . . . . . . 59
SPECIAL TOOLS
2.5L ENGINE SPECIAL TOOLS . . . . . . . . . . . . . . 60
XJ
ENGINE
9 - 1
DESCRIPTION AND OPERATION
ENGINE
DESCRIPTION
The 2.5 liter (150 CID) four-cylinder engine is an
In-line, lightweight, overhead valve engine.
This engine is designed for unleaded fuel. The engine
cylinder head has dual quench-type combustion cham-
bers that create turbulence and fast burning of the air/
fuel mixture. This results in good fuel economy.
The cylinders are numbered 1 through 4 from front
to rear. The firing order is 1-3-4-2 (Fig. 1).
The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within five main bearings and the camshaft rotates
within four bearings.
The engine Build Date Code is located on a
machined surface on the right side of the cylinder
block between the No.3 and No.4 cylinders (Fig. 2).
The digits of the code identify:
• 1st Digit—The year (8 = 1998).
• 2nd & 3rd Digits—The month (01 - 12).
• 4th & 5th Digits—The engine type/fuel system/
compression ratio (HX = A 2.5 liter (150 CID) 9.1:1
compression ratio engine with a multi-point fuel
injection system).
• 6th & 7th Digits—The day of engine build (01 - 31).
FOR EXAMPLE: Code * 801HX23 * identifies a
2.5 liter (150 CID) engine with a multi-point fuel
injection system, 9.1:1 compression ratio and built on
January 23, 1998.
LUBRICATION SYSTEM
DESCRIPTION
A
gear—type
positive
displacement
pump
is
mounted at the underside of the block opposite the
No. 4 main bearing.
OPERATION
The pump draws oil through the screen and inlet
tube from the sump at the rear of the oil pan. The oil
is driven between the drive and idler gears and
pump body, then forced through the outlet to the
block. An oil gallery in the block channels the oil to
the inlet side of the full flow oil filter. After passing
through the filter element, the oil passes from the
center outlet of the filter through an oil gallery that
channels the oil up to the main gallery which
extends the entire length of the block.
Galleries extend downward from the main oil gallery
to the upper shell of each main bearing. The crankshaft
is drilled internally to pass oil from the main bearing
journals (except number 4 main bearing journal) to the
connecting rod journals. Each connecting rod bearing
cap has a small squirt hole, oil passes through the
squirt hole and is thrown off as the rod rotates. This oil
throwoff lubricates the camshaft lobes, distributor drive
gear, cylinder walls, and piston pins.
The hydraulic valve tappets receive oil directly
from the main oil gallery. Oil is provided to the cam-
shaft bearing through galleries. The front camshaft
bearing journal passes oil through the camshaft
Fig. 1 Engine Firing Order
Fig. 2 Build Date Code Location
1 – NO. 4 CYLINDER
2 – NO. 3 CYLINDER
3 – DAY
4 – MONTH
5 – YEAR
6 – MACHINED SURFACE
9 - 2
2.5L ENGINE
XJ
sprocket to the timing chain. Oil drains back to the
oil pan under the number one main bearing cap.
The oil supply for the rocker arms and bridged
pivot assemblies is provided by the hydraulic valve
tappets which pass oil through hollow push rods to a
hole in the corresponding rocker arm. Oil from the
rocker arm lubricates the valve train components,
then passes down through the push rod guide holes
in the cylinder head past the valve tappet area, and
returns to the oil pan.
XJ
2.5L ENGINE
9 - 3
DESCRIPTION AND OPERATION (Continued)
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст