1991 MITSUBISHI 3000GT check engine

ENGINE - Enaine AssemblvII-19
Engine mount bracketSERVICE POINTS OF REMOVALMllSBEH
15. DISCONNECTION OF Ail? CONDITIONER COMPRES-SOR
/ 16. POWER STEERING OIL PUMP
Disconnect air conditioner compressor and power steering
oil pump (with the hose).
NOTEThe removed air conditioner compressor and power steer-
ing oil pump should be fastened (by using rope, etc.) in
.aposition that will not interfere with the removal/installation
of the engine assembly.
34. REMOVAL OF ENGINE MOUNT BRACKETBefore removing the engine mount bracket installation bolt,
use a chain block or similar arrangement to suspend the
engine assembly (to the extent that there is no looseness of
the chain).
37. REMOVAL OF ENGINE ASSEMBLYAfter checking that the cables, hoses, harness connectors,
etc. are all removed, slowly raise the chain block to lift the
engine assembly upward out of the engine compartment.
SERVICE POINTS OF INSTALLATIONMl
1SDBC
37. INSTALLATION OF ENGINE ASSEMBLYWhen mounting the engine, check to be sure that the
cables, hoses, harness connectors, etc. are all in the correct
position.
34. INSTALLATION OF ENGINE MOUNT BRACKETAttach the engine mounting bracket so that the arrow mark
on the mounting stopper is in the direction as shown in the
illustration.
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ENGINE - Timinn Belt11-27
r bol
I01 NO07
10. REMOVAL OF ENGINE SUPPORT BRACKETRemove the engine support bracket in the numbered
sequence shown in the illustration.
Spraying lubricant, slowly remove the bolt (reamer bolt)
indicated by the arrow.
CautionKeep in mind that the reamer bolt is sometimes heat
seized on the engine support bracket.
Timing mark
mshaftrocket01 N009:
d Soft jawSoft jaw
OlL104E
Set hole
n
12. REMOVAL OF TIMING BELT(1) Align the timing marks.
(2) Make a mark on the back of the timing belt indicating
the direction of rotation so it may be reassembled in the
same direction if it is to be reused.
(3) Loosen the center bolt on the tensioner pulley to
remove the timing belt.
Caution
Water or oil on the belt shorten its life drastically, sothe removed timing belt, sprocket, and tensioner
must be free from oil and water. These parts should
not be washed. Replace parts if seriously contamin-
ated.
If there is oil or water on each part check. the front
case oil seals, camshaft oil seal and water pump for
leaks.SERVICE POINTS OF INSTALLATION
MllKDDB
13. INSTALLATION OF AUTO TENSIONER
(‘I) If the auto tensioner rod is in its fully extended position,
reset it as follows.@ Keep the auto tensioner level
and: in that position,
clamp it in the vise with soft jaws.@ Push in the rod little by little with the vise until the
set hole @ in the rod is aligned with that @ in the
cylinder.
CautionPush in the rod slowly to prevent the push rod
from being damaged.@ Insert a wire [I
.4 mm (.055 in.) in diameter] into the
set
ho&.@ Unclamp the auto tensioner from the vise.
(2) Install the auto tensioner.
CautionLeave the wire installed in the auto tensioner.
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ENGINE - Timing Belt11-29
OlN004t
& Pin hole
nilnq
8(2) Using paper clips, install the timing belt in the following
order with care not to allow the belt to slack.@ Exhaust camshaft sprocket (front bank side)
+ @
Intake camshaft sprocket (front bank side)
-+ @Waterpump pulley
+ @ Intake camshaft sprocket (rear bank
side)
+ @ Exhaust camshaft sprocket + @ Idler pulley
-+ @ Crankshaft sprocket + @ Tensioner pulley
NOTESince the camshaft sprockets turn easily, secure them
with box wrenches to install the timing belt.
Caution1. Be careful, the camshaft is turned by the reac-
tion of valve spring.
2.If the timing belt is reused, install it so that thearrow marks made at removal are in the direc-
tion of rotation.
(3) Turn the tensioner pulley so that its pin holes are
located above the center bolt. Then, press the tensioner
pulley against the timing belt and, at the same time,
temporarily tighten the center bolt.
(4) Check that the timing marks on all sprockets are aligned
properly.
(5) Remove the four clips.
. ADJUSTMENT OF TIMING BELT TENSION
(1) Rotate the crankshaft
114 turn counterclockwise, then
rotate it clockwise until the timing marks are aligned.
(2) Loosen the center bolt on the tensioner pulley. Using
the special tool and torque wrench, apply tensioning
torque to the timing belt and, at the same time, tighten
the center bolt to specification.
Specified torque:
10 Nm (7 ftlbs.)
[Timing belt tensioning torque]
Caution
When tightening the center bolt, make sure that thetensioner pulley is not rotated together.
(3) Remove the set pin from the auto tensioner. At this
time, make sure that the set pin can be easily removed.
(4) Rotate the crankshaft two turns clockwise and leave it
as is for five minutes or more. Then, check again that
the set pin can be easily removed from, and installed to,
the auto tensioner.
NOTEEven if the set pin cannot be easily inserted, the auto
tensioner is normal if its rod protrusion is within
specification.
Standard value (A): 3.8
- 4.5 mm (.I49 - .I77 in.)
If the protrusion is out of specification, repeat steps (1)
to (4).
(5) Check again that timing marks on all sprockets are
aligned properly.
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11-32ENGINE - Rocker Arm and Camshaft
r
I
/7EN024E
Small wire
8ENOO58
Identification mark(stamped on hexagon section)
7EN0249
Front sideINSPECTION
MllZCAB
CAMSHAFTMeasure cam height (longer diameter of the cam). If it exceeds
the limit, replace the camshaft.
Standard value:
Intake side
35.49 mm (1.3972 in.)
Exhaust side
35.20 mm (1.3858 in.)
Limit:
Intake side
34.99 mm (1.3776 in.)
Exhaust side
34.70 mm (1.3661 in.)SERVICE POINTS OF INSTALLATION
MllZDAK
11. INSTALLATION OF LASH ADJUSTER
(1) Immerse the lash adjuster in clean diesel fuel.
(2) Using a small wire, move the plunger up and down 4 or
5 times while pushing down lightly in the check ball in
order to bleed out the air.
(3) Install the lash adjuster to the cylinder head.
9. INSTALLATION OF CAMSHAFT
(1) Turn the crankshaft to bring No.1 cylinder to the top
dead center.
(2) Check that the rocker arm is installed correctly on the
lash adjuster and valve.
(3) Install the camshaft noting the identification mark
(stamped on the hexagon sectioned).
Identification mark: Intake sideV
Exhaust side C
(4) Install the camshafts with their dowel pins positioned
as shown in the illustration.
Rear side ,
Approx. 100”
Pl
Frontm&k
M
0
/
Cap No
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Identificationmark
7EN03168. 7. 6. 4. 2. INSTALLATION OF BEARING CAPS
(1) Install noting the identification mark and cap No. No.2, 3
and 4 bearing caps bear the front mark. Install these
caps with the mark lined up with the front mark on the
cylinder head.
Identification mark: Intake side
IExhaust side E

11-36ENGINE - Cylinder Head and Valve
SquarenssVALVE SPRINGS
(1) Check free length of each valve spring and replace if
necessary.
!
FreelengthStandard value: 46.9 mm
(1.846 in.)\bJLimit: 45.9 mm
(1.807 in.)
(2) Using a square, test squareness of each valve spring. If
spring is excessively out of square, replace it.
Standard value: Less than 2”
Limit: 4
1 EN035
VALVE GUIDES
1 EN29ECheck the valve stem-to-guide clearance. If the clearance
exceeds the service limit, replace the valve guide with new
oversize part.
Standard value:
Intake
Exhaust0.02 - 0.05 mm (0008 - .0020 in.)
Limit:0.05
- 0.09 mm (.0020 - .0035 in.)
Intake
Exhaust0.10 mm (0039 in.)
0.12 mm (0047
in.)6EN043
1AVALVE SEAT RECONDITIONING PROCEDURES
(I 1 Before valve seat reconditioning, check valve stem to guide
clearance.
(2)Recondition the valve seat with a seat grinder or cutter. The
valve seat width should be the specified value at the center
of the valve face.
Inspect the valve seat with prussian blue to determine
LJwhere the valve contacts the seat. To do this, coat valve
seat lightly with prussian blue, and then set valve in place.
Rotate the valve with light pressure. If the blue is
transferred to the center of valve face, contact is satisfac-
tory.
If the blue is transferred to top edge of the valve face, lower
valve seat with a 30 degrees stone or cutter. If the blue is
transferred to the bottom edge of valve face, raise valve
seat with a 65 degrees stone or cutter.
Valve seat diameter:
Intake34 mm (I .34 in.)
ExhaustSeat width: 0.9
29.5 mm (1.16 in.)
- 1.3 mm (035 - .051 in.)
(3) The valve and valve seat should be lapped with a lapping
compound.
VALVE SEAT REPLACEMENT PROCEDURE
(1) Grind the valve seat to be replaced from the inside to thin
the wall thickness. Then, remove the valve seat.
1 ENOE18
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ENGINE - Oil Pan and Oil Pump
Removal steps
1. Transaxle stay (front)
2. Transaxle stay (rear)
3. Oil pressure switch4.
Z:
;:9.10.l+11.l*12.** l * 13.
Oil pressure gauge unitOil filterOil cooler by-pass valve
Oil filter bracket stay
Oil filter bracket
Oil filter bracket gasket
Drain plugDrain plug gasket0; y; boltI
16. Relief plug17. Relief spring18. Relief plunger** 19. Crankshaft front oil seal
20. Oil pump case
21. Oil pump gasket
22. Oil pump cover
23. Oil pump outer rotor
24. Oil pump inner rotor
14. Oil screen
15. Oil screen gasket
Side
clearance
BodyclearanceSERVICE POINTS OF REMOVALMllRBBB
13. REMOVAL OF OIL PAN
(1) Knock the special tool in deeply between the oil pan and
cylinder block.
(2) Hitting the side of the special tool, slide and remove the
oil pan.
INSPECTION
OIL PUMPMllRKAB
Assemble the rotor on the oil pump and check the clearance
with a feeler gauge.
Standard value:
Body clearanceO.lOO- 0.181 mm (.0039 - .0071 in.)
Side clearance0.040 - 0.095 mm (.0016 - .0037 in.)
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ENGINE - Piston and. Connectina RodII-45
LJ
Front mark
-
MD998764
lEN0113
lEN0114
v5EN057
,, Push in by thepiston.
IPiston ringPistonring gap6EN0379. REMOVAL OF PISTON PIN
(1) Insert the special tool,
Pushrod from the front mark side
of the piston top and install the guide B.
(2) With the piston top facing the front mark side of the
special tool, Piston Pin Setting Base and the piston front
mark facing up, set the piston and connecting rod
assembly.
(3) Using a press, remove the piston pin.
NOTEAfter the piston pin is removed, store the piston, piston
pin and connecting rod as grouped for each cylinder
number.
INSPECTION
PISTON RING
MllTCEA
(1) Check the clearance between the piston ring and the ring
groove. When it exceeds the limit, replace the rings, the
piston, or both.
Standard value:
No.10.03 - 0.07 mm (.0012 - .0028 in.)
No.20.02
- 0.06 mm (.OOOS - ‘0024 in.)
Limit: No.10.1 mm (.004 in.)
No.20.1 mm
(.004 in.)(2) Insert the piston ring into the cylinder bore putting it against
the top of the piston head and pressing it in.
When it makes a right angle, measure the piston ring gap
with a feeler gauge. When the gap is too large, replace the
piston ring.
Standard value:
No.10.30-0.45 mm (.0118- .0177 in.)
No.20.45- 0.60 mm (.0177 - .0236 in.)
Oil ring side rail0.20 - 0.60 mmLimit: No.1
(.0079 - .0236 in.)
0.8 mm
(.031 in.)
No.20.8 mm
(.031 in.)
Oil ring side rail1 .O mm (.039 in.)
I
LJ
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ENGINE - Piston and Connecting RodII-47
6EN0223
Side rail
Side rail end
7EN249
7EN250
ldentiftcation mark embossed
No. 1
7Barrel
weldenthcation mark
Tapered
we7EN013i
LI(7) Check that the piston moves smoothly.
8. INSTALLATION OF OIL RING
(1) Fit the oil ring spacer into the piston ring groove.
NOTEOn the side rail and the spacer, no difference exists
between the upper and the lower surfaces.
(2) Attach the side rail on the upper side. When attaching
the side rail, engage one side of the side rail with the
piston groove. If pressed with a finger, as shown in the
illustration, it should enter easily.
NOTEThe side rail may be broken like other piston rings if the
gap is opened by the ring expander.
(3) In the same procedure as Step
(2), position the side rail
on the lower side.
(4) Check that the side rail smoothly rotates in both
directions.
7.INSTALLATION OF PISTON RING No. 2 / 6. PISTON
RING No.1
(1) Using a piston ring expander, position the No.2 and
No.1 piston rings.
Identification mark: No.1
No.2
NOTE
T
T2(1) Keep in mind that Nos.1 and 2 are different in shape.
(2) Assemble the Nos.1 and 2 piston rings with the
manufacturer and size marks stamped on the side
facing upward (toward the piston top).
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