1991 MITSUBISHI 3000GT check oil

ENGINE - Service Adjustment Procedures11-15COMPRESSION PRESSURE CHECKMllFFAK
(1) Before checking compression, ensure that engine oil, the
starter motor, and battery are all in normal operating
condition.
(2) Start the engine and wait until engine coolant temperature
has risen to 80
- 95°C (176 - 205°F).
(3) Remove the all spark plugs.
(4) Crank the engine to remove any foreign objects in the
cylinders.
CautionCover the spark plug holes with shop towel, etc., in
order to keep expelled foreign objects from flying out,and keep away from the holes. When measuring
compression with water, oil, or fuel having entered the
cylinder through a crack, etc., these will come flying out
of the spark plug hole hot and fast, so be sure to take
the proper precautions.(5) Set the compression gauge to the spark plug hole.
(6) Holding the throttle valve full open, crank the engine and
measure compression.
Limit:
min. 980 kPa (139 psi)
min. 810 kPa (115 psi)(7) Perform (5) and (6) above for all the cylinders, ensuring that
compression pressure differential for each of the cylinders
is within the specified limit.
Limit: max.
100 kPa (14 psi)
(8) If a cylinder’s compression or pressure differential exceeds
the limit, add a small amount of oil through the spark plug
hole and repeat steps (5)
- (7).@If the addition of oil brings compression up, it is possible
that there is
harmf,uI friction between the piston ring
and cylinder wall.@If not compression up, valve seizure, poor valve seating,
or a compression leak from the gasket are all possible.
TSB Revision

11-16ENGINE - Service Adjustment Procedures
MANIFOLD VACUUM INSPECTION
MllFNAR
(1) The vehicle should be repaired as follows before the
inspection.
lEngine coolant temperature: 80 - 95°C (176 - 205°F)‘dl Lights, electric cooling fan, and accessories: OFF
l Transaxle: Neutral
(P for A/T)l Steering wheel: neutral position
(2) Connect a tachometer. (Refer to P.l l-l 3.)
(3) Disconnect the vacuum hose from the nipple for taking off
fuel pressure regulator vacuum from the air intake plenum.
(4) Conncet a three-way joint between the removed vacuum
hose and the nipple and connect a vacuum gauge to the
joint.
(5) Start the engine and check that idle speed is within the
standard value range.
(6) Check the manifold vacuum.
Standard value:
*
Approx. 520 mmHg (20 in.Hg)
Approx. 495 mmHg (19 in.Hg)LASH ADJUSTERS CHECK
Ml 1 FEAFIf an abnormal noise is heard from the lash adjusters, check as
follows.
(1) After warming up the engine, stop it.
(2) While installed to the cylinder head, press the part where
the rocker arm contacts the lash adjuster at the very top. If
the adjuster is normal, the part pressed will feel very hard.
d
(3) If it easily moves all the way downward when pressed,
there is a malfunction of the lash adjuster and it should be
replaced with a new one.
(4) If it feels spongy or elastic, probably oil with air mixed in it
has entered the lash adjuster. Check whether the amount
of oil is too much or is not enough and the cause of air
becoming mixed into the oil is a damaged oil screen or oil
screen gasket.
(5) After repairing the cause of the air leak, warm up the engine
and then drive the vehicle at low speed for a while. Stop the
engine and leave it off for a few minutes; then restart the
engine and drive at low speed. Repeat this procedure
several times during the course of about one hour so as to
remove the air from the oil.
TSB Revision

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.
TSB Revision

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.
1 TSB Revision

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.)
TSB Revision

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
TSB Revision1

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).
TSB Revision

11-48ENGINE - Piston and Connecting Rod
Side railNo.1
spacer slotrail
6ENO41
7EN0032
Cylindcnumbe
Stopper notch4. INSTALLATION OF PISTON, CONNECTING ROD~
ASSEMBLY
(1) Liberally coat engine oil on the circumference of the
piston, piston ring, and oil ring.
d
(2) Arrange the piston ring and oil ring gaps (side rail and
spacer) as shown in the illustration.
(3) Rotate crankshaft so that crank pin is on center of
cylinder bore.
(4) Use suitable thread protectors on connecting rod bolts
before inserting piston and connecting rod assembly
into cylinder block. Care must be taken not to nick crank
pin.(5) Using a suitable piston ring compressor tool, install
piston and connecting rod assembly into cylinder block.
Caution
Insert the pistons so that the front marks (arrows)on the piston tops point toward the front of the
engine (timing belt side).
2. INSTALLATION OF CONNECTING ROD CAP
(1) Install the connecting rod, aligning it with the mark
made or the connecting rod cap during disassembly.
When the connecting rod being installed is new and has
no alignment mark, install it so that the notches in the
connecting rod and cap are on the same side, as
illustrated.
‘d(2) Check the connecting rod big end thrust clearance.
Standard value: 0.10
- 0.25 mm (.0039 -‘.0098 in.)
Limit: 0.4 mm
(-016 in.)
TSB Revision