2006 MITSUBISHI COLT engine

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-14
VALVE STEM SEAL
AK305079AB
Valve stem seal
The valve stem seal e m ploys springs to enh ance
sealing p
e rformance , min i mi zing oil p a ssing do wn to
the por
t.
VALV E S P R I N G
AK300721AB
h
The valve spri ng h a s a dual pitch sp ring to prevent
surging in the h
i gh speed range .
ItemSpecification
Free length mm43.1
No. of spring turns8.49
VA L V E T A PPET
AK300722AB
Thickness
Identification mark
Va lve t app et s are avai lable in 31 th ickne sses, at 0. 02
mm
intervals betwee n 2.70 mm and 3 . 30 mm, to
ensu
r e co rrect valve clearan ce.

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-15
MIVEC (MITSUBISHI INNOVATIVE VALVE TIMING ELECTRONIC CONTROL SYSTEM)
AK300856AD
A
A
A-A
Oil feeder control valve
Oil feeder
control
valve filter
Oil feeder
control
valve filter
bolt
Cylinder head
Cylinder block
V.V.T.sprocket
M I VEC (Mit su bis h i Inn o va tive V a lve tim i ng Elect r o n ic
Con
t rol system) consist s of th e compon ent s illus
-
trated above .
The int a ke valve timing is optimally controlled (con-
tinuously variable) un der the chan ging driving condi-
tions to improv e po we r in th e entire sp eed ra nge.
V. V . T . SPROCKET (V ARIABLE V A L V E TIMING SPROCKET)
AK300857
Vane bushing
AB
SprocketVane roter
V.V.T.sprocket
bolt
Timing mark
Vane housing
Advance oil chamber
Retard oil chamber
Stopper pin
Oil from the oil fe
eder control valve is sent t o the
V
. V . T . sp rocket, moving the vane roto r and thus reg u
-
lating the valve timing.

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-16
CAMSHAFT
AK304999
Intake camshaft
Exhaust camshaft
AB
Hollow section
Advance
oil channel
Retard
oil channel
Cam positon sensing ring
Dowel pinSealing cap
The lightweight camshaf t is ach i eved by the h o llo w
design.
Oil channels run through the int a ke camshaf t,
through
wh ich oil is sent from t he oil fee der co ntrol
valve to
the V . V . T . sprocket.
A cam position sen s in g ring is press-fitt ed onto the
rear port
i on o f the int a ke camshaf t.
ItemDimension
Overall length
mmIntake407.5
Exhaust361.9
Journal mm26
Valve lift mmIntake8.4
Exhaust7.9
OIL FEEDER CONT ROL V A L V E(OCV)
AK302997AB
Spring guideValve sleeve
Plunger spring Spool
O-ring
Insulation coilar
StatorGuide cap Bracket
Yo k eSeal cap
Plunger
Shaft Terminal
Bobbin
Tape
Enameled copper wire
Drain
Drain
Pump
Pressure
chamber
Default
pressure
chamber
The oil fee
der co ntrol valve is essen t ially a solenoid
valve, re
gulat ed by the en gine -ECU or
engin
e -A-M/T -ECU signals to feed o il to the V . V . T .
sprocket
assemb ly t o move the van e rotor .

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-17
TIMING CHAIN CASE
AK305243
Engine support bracket
AB
The engine supp ort bracket, the oil pu mp a nd the
relie
f valve are in tegrate d as we ll as water chamber
of the wat
e r pump.

GENERAL INFORMATION
ENGINE MECHANICAL <4A9>11A-18
GENERAL INFORMATION
M2112000101009
The newly developed 1.5L 4A91 engine features
4-cylinder, 16-valve, and double overhead camshafts
(DOHC).
The engine has the following features.
•Aluminum cylinder block
•MIVEC (Mitsubishi Innovative Valve timing Elec-
tronic Control system)
•Selective valve tappet of direct acting valve sys-
tem for valve clearance adjustment
•Timing chain
MAJOR SPECIFICATIONS
Item4A91
Total displacement mL1,499
Bore × Stro ke mm75 × 84.8
Compression ratio10.0
Compression chamberPentroof-type
Va l v e t i m i n gIntake openingBTDC 31° − AT D C 1 9°
Intake closingABDC 21° − ABDC 71°
Exhaust openingBBDC 39°
Exhaust closingATDC 5°
Maximum output kW (PS)/rpm77 (104)/6,000
Maximum torque N⋅m (kg⋅m)/rpm141 (14.4)/4,000
Fuel systemElectronically controlled multipoint fuel injection
Ignition systemElectronic-controlled 4-coil

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-19
BASE ENGINE
M2112001000875
CYLINDER HEAD
AK305050AB
Spark plug guide
Intake
side
Exhaust
side
Valve guide
The cylinder head is made of aluminu m alloy , which
is light
we ight a nd ha s an excelle nt co oling ef ficiency .
The pentroof type comb ustion chamb e r has a sp a r k
plug in the
cent er . The valve an gle is relatively small,
contributing to size redu
ctio n.
The int a ke an d exhaust port s a r e arrang ed in a
cross-flow construction.
Ea ch cylinde r has a p a ir of
int
a ke port s on one side and a p a ir of e x hau st po rt s
on the
other side .
Each o f the int a ke a nd exhaust ca msh a f t s is sup-
ported by 5 bearin gs. On ea ch camshaf t, th e thrust
load
is suppo rted by No. 1 b earin g. The No . 1 bea r
-
ings for the int a ke and exha ust camshaf t s ha ve a
common bearing
ca p.
VALV E S E AT
AK305052
d
AB
d
DD h
h
Intake
Exhaust
Sintered
alloy valve seat
ItemIntakeExhaust
D (Outer
diameter) mm31.528
d (Inner
diameter) mm2622
h (height) mm6.67.3

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-20
VA LV E G U I D E
AK305053
d
AB
Dh
The in
t a ke an d exhaust valves use the same -design
valve gu
ide.
ItemIntake
D (Outer diameter) mm10.5
d (Inner diameter) mm4.5
h (height) mm34.5
CYLINDER HEAD GASKET
AK305054AB
Water hole
Oil hole
Water hole
Th e met a l g a sket having he at resist ance, sea l ability
and low cost is use
d for th e cylin der hea d gasket .
CYLINDER HEAD COVER
AK402398AC
Cylinder head cover
A resin cylin der hea d co ver is used fo r the cylinder head.

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-21
CYLINDER BLOCK
AK402339AC
Front view
Right side view
Under view
Top view
Rear view
Left side view
Thermostat case installation positionOil filter bracket installation position Front
Front Front Front
Nipple
The cylinder b
l ock is ma de of ligh twe i ght aluminum
allo
y .
The crankshaf t jo urnal is supp orted b y 5 b earing s .
The crankshaf
t thru st load is supporte d by No . 4
bearin
g.
The water jacket is of a full-siamese de sig n .
A nipple is p r ovid ed at the fr o n t of the block to su pply
engin
e oil onto the timin g ch ain.
ItemDimension
Overall height mm280
Overall length mm375.1
Top face to crankshaft
center mm205
Crankshaft center to
bottom face mm75
Bore mm75
Bore pitch mm83
Stroke mm84.8