timing belt MITSUBISHI ECLIPSE 1990 Service Manual

GENERAL - Technical Featureso-5ENGINE
The engines are the transverse-mounted engine
especially for front-engine/front-wheeldrive orfront-engine/4-wheel drive models, the
2.OL DOHC
16-valve engine with high-performance, silent-
operation,low-vibration,low-noise,low-fuel-
consumption features, an engine that fully displays
the most
up-todate engine technology.
SPECIFICATIONS
Engine model
Displacement
cc (cu.in.1
h$xo$put (SAE net)Max. torque (SAE net)
ft.Ibs./rpm
4G63Non-Turbo1997(122)135/6000125/5000
4663Turbo1997(122)195/6000203/3000
FEATURESHigh performance and low fuel consumption
l The rocker arm reduces the valve-actuation torque as well as fuel consumption.
l Air-intake efficiency improved through the adoption of the optimum air-intake system layout.
l Improved response and fuel consumption has been achieved by electronic control multipoint
fuel injection.
l Water-cooled turbocharger.
Quiet operation
l Noise and vibration have been decreased by the adoption of roller rocker arms.
l Noise generated by the valve mechanism has been decreased by the hydraulic auto lash adjusters.
l Vibrations have been decreased by the adoption of bearing caps with beams which increase the
rigidity of the crankshaft support points.
-Serviceability
l Complete self-diagnosis functions.
l Enhanced reliability through the adoption of gold-plated connector terminals.
l Use of an auto tensioner achieves maintenance-free, automatic adjustment of timing belt
tension.
l Use of the auto lash adjusters achieves maintenance-free, automatic adjustment of valve clearance
.o The 2coil ignition system without a distributor supplies sufficient ignition energy even during
high speed operation.

O-6GENERAL - Technical Features
Valve mechanisml The roller rocker arms de-crease losses.due to friction in
the valve system.
l The auto lash adjusters elimin-ate the need to adjust the valve
clearance.
ICombustion chamberThe combustion chamber is pro-
vided with a squish area for high
combustion efficiency.
tJ
Ignition systemThe 2coil ignition system without
a distributor supplies sufficient
ignition energy even in the high
speed operation.
76-4 Crankshaft pu!leyThe oullev orovrded with a torsion-
al
da’mper ieduces the transmis-
sion of vibrations.
EN0376
Auto tensionerThe auto tensioner eliminates the
need to adjust the timing belt
tension.
]Icrankshaft has five marn bearings

q7 --_-.-ENGINE
- General Information9-3TECHNICAL FEATURES
HIGH PERFORMANCE AND . . .._..............1. The DOHC 16-valve engine ensures excellent intake and exhaust
FUEL ECONOMYefficiency.
2. The rocker arm is of the roller-type-cam-follower design which Iminimizes friction loss.
3. The combustion chamber is of the pentroof type with a squish
area that offers outstanding combustion efficiency.
4. The multipoint fuel injection system is electronically
controlled.5. The intake manifold is the inertia supercharging type which
improves intake efficiency and the dual-type exhaust manifold
offers good exhaust efficiency.
6. The two-coil type electronic control ignition system ensures
good ignition performance.
LOW VIBRATION AND. . . . . . ..I.................1. The hydraulic lash adjuster, together with the roller rocker arm,
LOW NOISEcontributes to reduced operating noise of the valve mechanism.
2. A cogged type belt is used to drive the camshaft.
3. The auto tensioner maintains the optimum timing belt tension.
4. The torsional damper reduces twisting vibration in the crankshaft’
to a minimum.
5. The silent shaft system reduces engine vibration and rolling
’moment to a minimum
SERVICEABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1. The self-diagnosis system makes troubleshooting easier.
2. The lash adjuster eliminates the need for valve clearance
adjustment.3. The auto tensioner eliminates the need for timing belt
tension adjustment.
-.--..-. --.-

9-12
CRANKSHAFT PULLEY
ENGINE- Base EngineDrives the water
pump and alternator
Hub-
Pulley -Drives the air
conditioner
compressor
Fin
Rubber
6EMI2526EN0145 Timing belt cover
(1) The crankshaft pulley not only drives the water
pump and alternator, but also functions as a
torsional damper to reduce torsional vibration of
the crankshaft.
SILENT SHAFT SYSTEM(2) There are fins provided at the back of the pulley
that ventilate the inside of the timing belt cover:
when the pulley rotates, they draw air out of the._
timing belt cover.
Forward
@
/I
Center of crankshaftSilent shaft --
6ENl32The silent shaft system counteracts the secondaryreducing the vibration and noise generated by the
exciting moment in the engine’s vertical direction asengine. The system is exactly the same as that used
t uluv -well as the rolling moment, thereby drastically
in the conventional 4G63-SOHC engine.
-------_---.--- __.----_. _... ,.

ENGINE- Base Engine9-17CAMSHAR
Exhaust camshaftStamped identification mark
-
-
k--JL---J
No. 1 camsNo. 2 camsNo. 3 cams
No. 4 camsIntake camshaftIt’ II’ II1
NOTEJ = Journal
Crank angle sensor6EN0112
(1) Each camshaft is supported by the six bearings.(2) A hexagon between the No. 1 and No. 2 cams is
provided for holding the camshaft with a wrench
when loosening or tightening the
catishaftsprocket bolt.
TIMING BELT TRAIN
Exhmmt rid.Intake tide
Camshatt sprookec(No. of teeth: 461Camshaft sprocket(No. of teeth: 461
MN0139
6tNOl10
011 Pump stmoket(No. o! teeth: 18)
Crankshatr spmokst(No. of loath: 2416EN0114

9-18ENGINE- Base Engine
(1) The intake camshaft, exhaust camshaft, and the
oil pump are driven by a single timing belt.
(2) Timing belt tension varies at different engine
temperatures and ages of the belt. The autotensioner absorbs these changes in belt
ten+n,not only to prevent the noise problem
getting worse, but to improve durability as weli’l
AUTO TENSIONER
Piston -1
Check ball-4,
SpringTensioner
cwllev
6EN0116
LOoil seal
6ENOWThe auto tensioner applies tension to the timing belt
by causing the tensioner arm to move back and
forth in the directions shown by arrow
@I.The bottom figure shows the construction of the
aUt0 tensioner. The chambers on the right and leftof the piston
are filled with silicone oil.
Both the tensioner pulley and idler pulley are of the
ball bearing type into which grease has been
packed.