engine MITSUBISHI COLT 2006 Service Owner's Guide

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

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-22
REAR OIL SEAL CASE
AK305061AB
AA A-A
The rea
r oil seal ca se is a sheet -met al wor k . The
case is
inst alled with sealant ap plie d onto th e mou n t
-
ing face to prevent oil leaka ge.
PISTON
AK403222
AB
Front mark
Piston pin offset
The pisto n is made of spec ial a l uminu m all o y . W e ig ht
reduction
is a c hieved by minimizin g the o v erall
heigh
t while maximizing th e recess on bo th end s of
the piston
pin.
The center o f the p i sto n pin hole is of fset by 0.5 mm
from t
he ce nter of the piston towards the th rust side .
The piston skirt ha s a streak finish to enha nce oil
retention an
d anti-seizin g prope rty .
ItemDimension
Base diameter mm75
Pin diameter mm18
Overall height mm46.04
PISTON PIN
AK305064
d
AB
D
h
The piston pin is o f a semi-floating type, p r ess-fitte d
into t
he co nnecting rod small end wh ile cap able of
floating re
lative to the piston .
ItemDimension
D (Outer diameter) mm18
d (Inner diameter) mm11
h (Overall length) mm50

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-23
PISTON RING
AK305365AB
Piston ring No.1
Spacer RailMaker mark
Piston ring No.2
Oil ring Piston ring No.1
Piston ring No.2
Oil ring
Ea ch pisto n is provided with No. 1 and No. 2 com-
pression rings and an oil rin g .
ItemNo. 1 piston ringNo. 2 piston ringOil ring
ShapeBarrelUndercut3-piece
Surface treatment (Contact
face with cylinder)Ion platingParkerizedIon plating
Maker markNo mafking2RNo marking

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-24
CONNECTING ROD
AK305065AB
dD
L
The connecting rod is made of high ly rigid, forged
carb
on stee l. The rod p o rtion h a s an H- sha ped cro s s
section.
The connecting rod big end bearing is lu bricated
thr
oug h an oil p a ssage ru nn in g f r om the main jo urn a l
to the cranksha
f t p i n.
ItemDimension
d (Small end inner
diameter) mm18
D (Large end inner
diameter) mm43
L (Center distance) mm135.6
CONNECTING ROD BEARING
AK305309AB
H A
Identification
color
The up
per and lower conne ctin g rod b earin g halves
are id
entical.
The connecting rod be aring is e quip ped wit h back
met
a l. While the b earin g it se lf is ma de of a l uminum
allo
y , the back met a l is no rmally mad e of ste e l shee t.
The connecting rod be aring is n a rrower tha n the
bearin
g ca p, this is to minimize wear .
ItemDimension
H (Width) mm13.5
A (Thickness) mm1.5

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-25
CRANKSHAFT
AK305068AD
Oil pump drive
gear shaft
Crankshaft
sprocket
Crankshaft sensing ring
CrankshaftOil hole
Oil hole
Balance weightBalance weightBalance weight
A casted crankshaf
t is used for t he cr ankshaf t.
The crankshaft consist s o f 5 ma in be aring s an d 8
balan
ce weight s.
The crankshaft pins a r e arrang ed at 1 8 0° inte rval s.
The oil hole supply lu brication oil from t he jo urnal to
the crank p
i n.
A cranksha f t sprocket and an oil pump drive gea r
shaf
t are press-fit t ed on to the f r ont of the crankshaf t.
The crankshaft is also fitt ed with a crankshaf t sens-
ing ring.
CRANKSHAFT BEARING, THRUST BEARING
AK305070
Upper bearingOil groove
Oil hole
Identification
color
Lower bearing
Identification
color
AB
Thrust bearing
Groove
Front
The upp er cra n kshaf t bea ring (with oil groove) is
loca
ted on the cylinder block side wh ile the lo we r
bearin
g (witho ut oil groo ve) is he ld by the b earin g
cap.
The crankshaft bea ring is e quipp ed with back me t a l.
While the b
earin g it self is ma de of a l uminum alloy ,
the back met
a l is no rmally made of steel sheet .
A thrust bearing is inst alle d on b o th sides of th e No.
4 cran
kshaf t bearing.
ItemDimension
Crankshaft
bearingWidth mm16
Thickness mm20
Crankshaft
thrust bearingThickness mm3.275

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-26
CRANKSHAFT PULLEY
AK305072AD
Timing markDamper
A cast iron cranksh af t pulley is used.
The pulley has grooves to eng age with a V -rib bed
belt (5
ribs), which drives an alternat or and a water
pump
.
An ignition timing mark (notch) is st amp ed on the
flang
e of the pulley .
The crankshaft pulley is equipped with a to rsio nal
damp
e r to minimize the torsional vibratio n of th e
cranksha
f t as well as sub s t antia lly redu ce no ise and
vib
r ation at the high spee d rang e.
Flyw he el
AK600531
Ring gear
Flywheel
AB
A cast iron ring g ear is a shrink fit in th e iron casting
of
t h e f l yw he el. T h e f l yw he el is in st a l le d by tigh t e n i n g
six bolt
s .

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-27
DRIVE PLATE
AK401856Ring gearDrive plateAB
A cast iron
ring g ear is a shrin k fit in th e ste e l plate o f
the drive p
l ate. The drive p l ate is inst alled b y tighten
-
ing six bolts .

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-28
TIMING CHAIN TRAIN
AK305075
V.V.T. sprocket
AB
V.V.T. sprocket
timing mark
Timing chain mark
link plate (bule)
Camshaft sprocket
Camshaft sprocket
timing mark Timing chain mark
link plate (bule)
Timing chain mark
link plate (bule)
Crankshaft
sprocket
timing mark
Crankshaft sprocket
Timing mark
Timing chain
tensioner
Tensioner lever
Chain guide
Timing mark
The 2 camshaf
t s are driven by the t i ming chain via
the res
pec tive spro cke t s .
The timing cha i n, consist i ng o f 122 links, is an end-
less chain, conn ecting the cran ksh af t spro cke t with
the camshaf
t and V . V . T . spro cke t s .
The timing cha i n is eq uippe d with 3 mark link p l ates
(blue)
to co rrectly time t he 3 sprocket s with each
other
.
ItemNo. of
teeth
Camshaft sprocket36
V.V.T. sprocket36
Crankshaft sprocket18
TIMING CHAIN TENSIONER
AK305388AB
Retainer
Ball
Coil spring 1
Ball sheet
Coil spring 2
Cam
Pin
Plunger
The timing chain is tensione
d by th e timing chain te n-
sioner , which ha s a b u ilt-in plunge r with plunge r
springs.
The plunger in the timing chain tension e r dire ctly
push
e s th e tension lever , and the pre s sure aut omati
-
cally ad just s the timing chain tension.
A cam is provided t o lock th e plu nger in pla c e a f te r
the eng
ine stop s. This help s prevent the timing chain
from wob
b lin g just af ter th e eng ine st a r t s .
With the timing cha i n ten s io ner in st alled, do not
crank the
engin e in the reverse directio n. This will
force
the plunger to overcome the cam, or e v en
cause oth
e r problems.

BASE ENGINE
ENGINE MECHANICAL <4A9>11A-29
VALVE MECHANISM
AK305076AB
Exhaust valveIntake valve
Exhaust camshaft
Intake camshaft
Spark plug guide
Valve tappet
The valve mechanism is based on a 4-va lve DOHC
(Do
uble Over Head Camsha f t ) d e sign having the
camshaf
t on the u pper valve. Each cylin der has 2
int
a ke valves and 2 exh aust valves, arrang ed in a
V
- shape p a ttern.Camsh a f t rot a tion is transmitte d via va lve t a ppet s to
the respective
valves which ope n and close accord
-
ingly.
VALV E
AK305078
d
d
DD
L
Intake
Exhaust
L
AB
The valves ha ve h eat-resist an ce. Th e entire valve
surface is trea
ted with gas nitriding.ItemIntake valveExhaust valve
Head diameter
mm30.525.5
Stem diameter
mm5.05.0
Overall length
mm89.6190.94