Mitsubishi 4G1 series Instruction manual

GENERAL INFORMATION 11A-0-3
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1. SPECIFICATIONS 11A-1-1
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SERVICE SPECIFICATIONS 11A-1-1
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REWORK DIMENSIONS 11A-1-3
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TORQUE SPECIFICATIONS 11A-1-4
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NEW TIGHTENING METHOD-BY USE OF BOLTS TO BE
TIGHTENED IN PLASTIC AREA 11A-1-6
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SEALANT 11A-1-6
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FORM-IN-PLACE GASKET 11A-1-7
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2. SPECIAL TOOLS 11A-2-1
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3. ALTERNATOR AND IGNITION SYSTEM 11A-3-1
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4. TIMING BELT 11A-4-1
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5. FUEL AND EMISSION CONTROL SYSTEM 11A-5-1
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6. WATER PUMP AND WATER HOSE 11A-6-1
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7. INTAKE AND EXHAUST MANIFOLD 11A-7-1
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8. ROCKER ARMS AND CAMSHAFT 11A-8-1
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9. CYLINDER HEAD AND VALVES 11A-9-1
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10. OIL PUMP AND OIL PAN 11A-10-1
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11. PISTON AND CONNECTING ROD 11A-11-1
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12. CRANKSHAFT, CYLINDER BLOCK 11A-12-1
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11A-0-1
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ENov. 1995Mitsubishi Motors Corporation
ENGINE
4G1 SERIES
CONTENTS

11A-0-2
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NOTES

4G1 ENGINE (E-W) - General Information 11A-0-3
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GENERAL INFORMATION

4G1 ENGINE (E-W) - General Information
11A-0-4
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4G1 ENGINE (E-W) - General Information 11A-0-5
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Descriptions 4G13 12-VALVE - CARBURETOR 4G13 12-VALVE-MPI
Type In-line OHV, SOHC In-line OHV, SOHC
Number of cylinders 4 4
Combustion chamber Pentroof type Pentroof type
Total displacement dm31,299 1,299
Cylinder bore mm 71.0 71.0
Piston stroke mm 82.0 82.0
Compression ratio 9.5 9.5
Number of Intake 8 8
valves
Exhaust 4 4
Valve timing Intake opens BTDC 14_BTDC 19_
Intake closes ABDC 48_ABDC 43_
Exhaust opens BBDC 55_BBDC 60_
Exhaust closes ATDC 13_ATDC 8_
Lubrication system Pressure feed, full-flow filtration Pressure feed, full-flow filtration
Oil pump type Trochoid type Trochoid type
Cooling system Water-cooled, forced circulation Water-cooled, forced circulation
Water pump type Centrifugal impeller type Centrifugal impeller type
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4G1 ENGINE (E-W) - General Information
11A-0-6
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Descriptions 4G13 16-VALVE-MPI 4G18 16-VALVE-MPI
Type In-line OHV, SOHC In-line OHV, SOHC
Number of cylinders 4 4
Combustion chamber Pentroof type Pentroof type
Total displacement dm31,299 1,584
Cylinder bore mm 71.0 76.0
Piston stroke mm 82.0 87.3
Compression ratio 10 9.5
Number of Intake 8 8
valves
Exhaust 8 8
Valve timing Intake opens BTDC 17_BTDC 17_
Intake closes ABDC 39_ABDC 39_
Exhaust opens BBDC 49_BBDC 49_
Exhaust closes ATDC 7_ATDC 7_
Lubrication system Pressure feed, full-flow filtration Pressure feed, full-flow filtration
Oil pump type Trochoid type Trochoid type
Cooling system Water-cooled, forced circulation Water-cooled, forced circulation
Water pump type Centrifugal impeller type Centrifugal impeller type
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4G1 ENGINE (E-W) - General Information 11A-0-7
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Descriptions 4G15-CARBURETTOR 4G15-MPI
Type In-line OHV, SOHC In-line OHV, DOHC
Number of cylinders 4 4
Combustion chamber Semi spherical type Pentroof type
Total displacement dm31,468 1,468
Cylinder bore mm 75.5 75.5
Piston stroke mm 82.0 82.0
Compression ratio 9.0 9.5
Number of Intake 8 8
valve
Exhaust 4 8
Valve timing Intake opens BTDC 14_BTDC 16_
Intake closes ABDC 48_ABDC 40_
Exhaust opens BBDC 55_BBDC 45_
Exhaust closes ATDC 13_ATDC 15 _
Lubrication system Pressure feed, full-flow filtration Pressure feed, full-flow filtration
Oil pump type Trochoid type Trochoid type
Cooling system Water-cooled, forced circulation Water-cooled, forced circulation
Water pump type Centrifugal impeller type Centrifugal impeller type
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NOTES

4G1 ENGINE (E-W) - Specifications 11A-1-1
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1. SPECIFICATIONS
SERVICE SPECIFICATIONS
Item Standard Limit
Rocker arms, rocker shafts, and camshaft
Camshaft cam SOHC 12-VALVE Intake (primary) 38.78 38.28
height mm Intake (secondary) 38.78 38.28
Exhaust 39.10 38.60
SOHC 16-VALVE Intake 36.99 36.49
Exhaust 36.85 36.35
DOHC Intake 34.67 38.28
Exhaust 34.26 38.60
Camshaft journal diameter mm SOHC 45.93 - 45.94 -
DOHC 25.95- 25.97 -
Cylinder head and valves
Flatness of cylinder head gasket surface mm 0.05 or less -
Cylinder head gasket surface grinding limit (including grinding of
cylinder block gasket surface) mm
- 0.2
Cylinder head overall height mm SOHC 12-VALVE 106.9- 107.1 -
SOHC 16-VALVE 119.9- 120.1 -
DOHC 131.9- 132.1 -
Cylinder head bolt nominal length mm -103.2
Valve margin mm Intake 1.0 0.5
Exhaust 1.5 1.0
Valve stem diameter mm SOHC 12-VALVE 6.6 -
SOHC 16-VALVE 5.5 -
DOHC 5.5 -
Valve stem-to-guide SOHC 12-VALVE Intake 0.020 - 0.050 0.10
clearance mm Exhaust 0.050 - 0.085 0.15
SOHC 16-VALVE Intake 0.020 - 0.047 0.10
Exhaust 0.030 - 0.062 0.15
DOHC Intake 0.020- 0.047 0.10
Exhaust 0.030- 0.062 0.15
Valve face angle 45_- 45.5_-
Valve stem projec- SOHC 12-VALVE Intake 43.70 44.20
tion mm Exhaust 43.30 43.80
SOHC 16-VALVE Intake 53.21 53.71
Exhaust 54.10 54.60
DOHC Intake 48.80 49.30
Exhaust 48.70 49.20
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4G1 ENGINE (E-W) - Specifications
11A-1-2
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Item LimitStandard
Overall valve length SOHC 12-VALVE Intake 100.75 100.25
mm Exhaust 101.05 105.55
SOHC 16-VALVE Intake 111.56 111.06
Exhaust 114.71 114.21
DOHC Intake 106.35 105.85
Exhaust 106.85 106.35
Valve spring free SOHC 12-VALVE Intake 46.1 45.6
height mm Exhaust 46.8 46.3
SOHC 16-VALVE 50.9 50.4
DOHC 49.1 48.6
Valve spring load/ SOHC 12-VALVE Intake 226/40.0 -
installed height N/
mm Exhaust 284/39.6 -
mm
SOHC 16-VALVE 216/44.2 -
DOHC 177/40.0 -
Valve spring squareness 2_4_
Valve seat contact width mm 0.9- 1.3 -
Valve guide internal diameter mm SOHC 12-VALVE 6.6 -
SOHC 16-VALVE 5.5 -
DOHC 5.5 -
Valve guide projection mm SOHC 12-VALVE 17.0 -
SOHC 16-VALVE 23.0 -
DOHC 23.0 -
Oil pump and oil pan
Oil pump tip clearance mm 0.06- 0.18 -
Oil pump side clearance mm 0.04- 0.10 -
Oil pump body clearance mm 0.10- 0.18 0.35
Pistons and connecting rods
Piston outside diameter mm 4G13 71.0 -
4G15 75.5 -
4G18 76.0 -
Piston ring side clearance mm No. 1 ring 0.02- 0.06 -
No. 2 ring 0.02- 0.06 -
Piston ring end gap clearance No. 1 ring 0.20- 0.35 0.8
No. 2 ring 0.35- 0.50 0.8
Oil ring 0.20- 0.50 1.0
Piston pin O. D. mm 18.0 -
Piston pin press-in load (at room temperature) N 4,900 - 14,700 -
Crankshaft pin oil clearance mm 0.02- 0.04 0.1
Connecting rod big end side clearance mm 0.10- 0.25 0.4
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4G1 ENGINE (E-W) - Specifications 11A-1-2a
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Item Standard Limit
Crankshaft and cylinder block
Crankshaft end play mm 0.05- 0.18 0.25
Crankshaft journal diameter mm 48.0 -
Crankshaft pin diameter mm 42.0 -
Crankshaft journal oil clearance mm 0.02- 0.04 0.1
Cylinder block gasket surface flatness mm 0.05 or less -
Cylinder block gasket surface grinding limit (including grinding of
cylinder head gasket surface) mm
- 0.2
Cylinder block overall height mm 256 -
Cylinder block cylindricity mm 0.01 -
Cylinder block I. D. mm 4G13 71.0 -
4G15 75.5 -
4G18 76.0 -
Piston-to-cylinder clearance mm 0.02- 0.04 -
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4G1 ENGINE (E-W) - Specifications
11A-1-2b
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4G1 ENGINE (E-W) - Specifications 11A-1-3
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REWORK DIMENSIONS
Item Standard Limit
Cylinder head and valves
Cylinder head oversize valve guide SOHC 12-VALVE 0.05 O. S. 12.050- 12.068 -
hole diameter mm 0.25 O. S. 12.250- 12.268 -
0.50 O. S. 12.500- 12.518 -
SOHC 16-VALVE 0.05 O. S. 10.550- 10.568 -
0.25 O. S. 10.750 - 10.768 -
0.50 O. S. 11.000 - 11.018 -
DOHC 0.05 O. S. 10.550 - 10.568 -
0.25 O. S. 10.750 - 10.768 -
0.50 O. S. 11.000 - 11.018 -
Oversize valve seat SOHC Intake (primary) 0.3 O. S. 27.300- 27.325 -
ring hole diameter
mm
12-VALVE 0.6 O. S. 27.600- 27.625 -
mm
Intake (secondary) 0.3 O. S. 32.300- 32.325 -
0.6 O. S. 32.600- 32.625 -
Exhaust 0.3 O. S. 35.300- 35.325 -
0.6 O. S. 35.600- 35.625 -
SOHC Intake 0.3 O. S. 28.300- 28.321 -
16-VALVE
<4G13> 0.6 O. S. 28.600- 28.621 -
<4G13>
Exhaust 0.3 O. S. 26.300- 26.321 -
0.6 O. S. 26.600- 26.621 -
SOHC Intake 0.3 O. S. 30.300- 30.321 -
16-VALVE
<4G18> 0.6 O. S. 30.600- 30.621 -
<4G18>
Exhaust 0.3 O. S. 28.300- 28.321 -
0.6 O. S. 28.600- 28.621 -
DOHC Intake 0.3 O. S. 31.300- 31.325 -
0.6 O. S. 31.600- 31.625 -
Exhaust 0.3 O. S. 27.800- 27.825 -
0.6 O. S. 28.100- 28.125 -
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EDec. 1998Mitsubishi Motors Corporation Revised

4G1 ENGINE (E-W) - Specifications
11A-1-4
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TORQUE SPECIFICATIONS
Item Nm
Alternator and ignition system
Water pump pulley bolt 9
Alternator brace (alternator side) 22
Alternator brace (tightened with water pump) 23
Alternator pivot bolt 44
Oil level gauge guide 23
Crankshaft bolt 125
Spark plug 25
Distributor 11
Ignition coil 10
Camshaft position sensor 9
Camshaft position sensor support 13
Camshaft position sensing cylinder 21
Timing belt
Timing belt cover 11
Timing belt tensioner 23
Crankshaft angle sensor (Rear wheel drive) 9
Engine support bracket (left) 35
Idler pulley 35
Camshaft sprocket bolt 88
Fuel system
Delivery pipe 11
Fuel pressure regulator 9
Throttle body 18
Fuel pump 11
Breather tube 22
Carburetor 17
Air temperature sensor 13
EGR valve 21
Water pump
Water inlet fitting 22
Water inlet pipe assembly 12
Water inlet pipe M6 12
M8 25
Fitting (Rear wheel drive) 23
Water outlet fitting (Rear wheel drive) 23
Thermostat case 23
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4G1 ENGINE (E-W) - Specifications 11A-1-5
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Item Nm
Thermo valve 27
Water temperature gauge unit 11
Water temperature sensor 29
Water pump 13
Exhaust manifold and intake manifold
Boost sensor 5
Solenoid valve assembly 9
Intake manifold 17
Intake manifold stay (MPI) M8 17
M10 21
Intake manifold stay (carburetor) 29
Exhaust manifold cover 29
Exhaust manifold M8 17
M10 29
Oxygen sensor 44
Rocker arms, rocker shafts, and camshaft
Fuel pump cover 12
Rocker cover 4
Rocker shaft assembly 31
Adjusting screw 15
Bearing cap 24
11
Cylinder head and valves
Cylinder head bolt 20 + 90_+90
_
Tighten to 49 Nm, then completely loosen and retighten as described.
Oil pump and oil pan
Transmission stay 23
Oil pan 7
Drain plug 39
Oil screen 18
Front case 13
Relief plug 44
Oil pump cover 10
Pistons and connecting rods
Connecting rod nut 17 + 90_to 100_
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4G1 ENGINE (E-W) - Specifications
11A-1-5a
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Item Nm
Crankshaft and cylinder block
Flywheel 132
Drive plate 132
Rear plate 10
Bell housing cover 10
Rear oil seal case 11
Bearing cap bolt 51
Oil pressure switch 18
Knock sensor 23
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4G1 ENGINE (E-W) - Specifications 11A-1-5b
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4G1 ENGINE (E-W) - Specifications
11A-1-6
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NEW TIGHTENING METHOD USING PLASTIC REGION TIGHTENING BOLTS
Parts of the engine use plastic region tightening bolts. The tightening procedure for these is different
from that of conventional bolts and is described in relevant parts of this manual. Note that plastic region
tightening bolts have fixed service limits. These limits are indicated in relevant parts of this manual and
must be strictly observed.
DPlastic region tightening bolts are used for the following applications:
(1) Cylinder head bolts
(2) Connecting rod cap bolts
DThe tightening procedure is basically as follows:
After tightening a bolt to the specified torque, tighten it by a further 90 _+90
_or by a further 90–100°.
The exact tightening procedure differs depending on the bolt and is described in relevant parts of
this manual.
SEALANTS
Item Specified sealant Quantity
Water pump Mitsubishi Genuine Part No. MD970389 or equivalent As required
Thermo valve Mitsubishi Genuine Part No. MD970389 or equivalent As required
Engine coolant temperature sensor 3M Nut Locking Part No. 4171 or equivalent As required
Engine coolant temperature gauge unit 3M ATD Part No. 8660 or equivalent As required
Camshaft bearing cap 3M ATD Part No. 8660 or equivalent As required
Semi-circular packing 3M ATD Part No. 8660 or equivalent As required
Rocker cover 3M ATD Part No. 8660 or equivalent As required
Front oil seal case Mitsubishi Genuine Part No. MD970389 or equivalent As required
Oil pump Mitsubishi Genuine Part No. MD970389 or equivalent As required
Oil pressure switch 3M ATD Part No. 8660 or equivalent As required

4G1 ENGINE (E-W) - Specifications 11A-1-7
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FORM-IN-PLACE GASKET
The engine has several areas where the form-in-place gasket (FIPG) is in use. To ensure that the gasket
fully serves its purpose, it is necessary to observe some precautions when applying the gasket. Bead
size, continuity and location are of paramount importance. Too thin a bead could cause leaks. Too thick
a bead, on the other hand, could be squeezed out of location, causing blocking or narrowing of the
fluid feed line. To eliminate the possibility of leaks from a joint, therefore, it is absolutely necessary to
apply the gasket evenly without a break, while observing the correct bead size.
The FIPG used in the engine is a room temperature vulcanization (RTV) type and is supplied in a 100-gram
tube (Part No. MD970389 or MD997110). Since the RTV hardens as it reacts with the moisture in the
atomospheric air, it is normally used in the metallic flange areas. The FIPG, Part No. MD970389, can
be used for sealing both engine oil and coolant, while Part No. 997110 can only be used for engine
oil sealing.
Disassembly
The parts assembled with the FIPG can be easily disassembled without use of a special method. In
some cases, however, the sealant between the joined surfaces may have to be broken by lightly striking
with a mallet or similar tool. A flat and thin gasket scraper may be lightly hammered in between the
joined surfaces. In this case, however, care must be taken to prevent damage to the joined surfaces.
For removal of the oil pan, the special tool “Oil Pan Remover” (MD998727) is available. Be sure to use
the special tool to remove the oil pan. <Except aluminium die-cast oil pans>
Surface Preparation
Thoroughly remove all substances deposited on the gasket application surfaces, using a gasket scraper
or wire brush. Check to ensure that the surfaces to which the FIPG is to be applied is flat. Make sure
that there are no oils, greases and foreign substances deposited on the application surfaces. Do not
forget to remove the old sealant remained in the bolt holes.
Form-In-Place Gasket Application
When assembling parts with the FIPG, you must observe some precautions, but the procedures is very
simple as in the case of a conventional precut gasket.
Applied FIPG bead should be of the specified size and without breaks. Also be sure to encircle the
bolt hole circumference with a completely continuous bead. The FIPG can be wiped away unless it is
hardened. While the FIPG is still moist (in less than 15 minutes), mount the parts in position. When
the parts are mounted, make sure that the gasket is applied to the required area only. In addition, do
not apply any oil or water to the sealing locations or start the engine until a sufficient amount of time
(about one hour) has passed after installation is completed.
The FIPG application procedure may vary on different areas. Observe the procedure described in the
text when applying the FIPG.

NOTES