MITSUBISHI MONTERO 1991 Owner's Manual

tensioner center bolt. Using Tensioner Pulley Socket (MD998767) and
torque wrench, apply 84 INCH lbs. (9.5 N.m). See Fig. 17. Retighten
center bolt to specification. See TORQUE SPECIFICATIONS (3000GT) table\
at end of article. Ensure tensioner pulley does not rotate while
tightening center bolt.
10) Ensure wire installed in automatic tensioner can be
easily removed and installed. Rotate crankshaft 2 revolutions
clockwise. Wait 5 minutes. Ensure wire can still be removed and
installed easily or automatic tensioner rod projects from tensioner
body .150-.177" (3.8-4.5 mm).
11) If rod projection is not to specification, repeat steps
9) and 10). To complete installation, reverse removal procedure.
Install proper length bolts in timing belt covers. Install bolts into
engine support bracket in reverse order of removal sequence. See
Fig. 10 . Tighten bolts to specification. See TORQUE SPECIFICATIONS
(3000GT) table.
NOTE: Engine support bracket reamer bolt must be tightened slowly
while spraying lubricant on bolt.
CAMSHAFT & ROCKER ARMS
Removal (SOHC)
1) Remove PCV valve and breather hoses. Remove timing belt,
camshaft sprocket and rear timing belt cover. See TIMING BELT under
REMOVAL & INSTALLATION. Remove rocker covers and gaskets. Remove
circular packing from rear of camshafts.
2) Remove camshaft oil seal from front of cylinder head or
distributor adapter. Remove distributor adapter and "O" ring. Install
Valve Lash Adjuster Holder (MD998443) on rocker arm. See Fig. 18. Note
arrow marks on bearing caps and cylinder head. See Fig. 19.
3) Bearing cap location number is stamped on front side of
bearing cap. Remove bearing cap bolts. Keep components in order for
reassembly reference. Remove rocker arm assembly. Remove camshaft from
cylinder head.
Fig. 18: Installing Valve Lash Adjuster Holder (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.

Fig. 19: Identifying Bearing Cap & Sealant Locations (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
Inspection (SOHC)
1) Remove bearing caps, rocker arms and springs from shafts.
Mark component location for reassembly reference. Inspect rocker arm
and shaft for damaged roller and flaking. Measure rocker arm I.D. and
rocker arm shaft O.D. Determine oil clearance. Check spring free
length. Replace components if not within specification. See ROCKER ARM
& SHAFT SPECIFICATIONS (SOHC) table.

2) Inspect camshaft and distributor gear for damage. Measure
camshaft end play, journal diameter and lobe height. Replace camshaft
if it is not within specification. See CAMSHAFT (SOHC) table under
ENGINE SPECIFICATIONS at end of article.
3) Coat components with oil. Reassemble rocker arms, springs
and bearing caps. Install bearing caps with identification number
toward camshaft sprocket. Ensure oil holes and notch of shafts are
properly positioned. See Fig. 19.
ROCKER ARM & SHAFT SPECIFICATIONS TABLE (SOHC)









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Application In. (mm)
Oil Clearance ................. ( 1).0004-.0016 (.010-.041)
Rocker Arm I.D. ............................ .7444 (18.91)
Rocker Arm Shaft O.D. ...................... .7440 (18.90)
Spring Free Length ......................... 2.173 (55.19)
( 1) - Maximum clearance is .0039" (.099 mm).









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Fig. 20: Installing Rocker Arm Shafts (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
Installation
1) Coat camshaft with oil, and install in cylinder head.

Install valve lash adjusters and valve lash adjuster holders (if
removed). See Fig. 18.
2) Apply 3M Sealant (4171) to designated areas of cylinder
head. See Fig. 19. Use care so sealant does not get on camshaft or
camshaft bearing journals. Install rocker arm assembly. Ensure arrow
on bearing cap faces same direction as arrow on cylinder head. See
Fig. 19 . Tighten bearing cap bolts to specification. See appropriate
TORQUE SPECIFICATIONS table at end of article. Remove valve lash
adjuster holders.
3) Coat camshaft oil seal area with oil. Using Seal Installer
(MD998713), install camshaft oil seal. Using Circular Packing
Installer (MD998306), install circular packing to press-in depth of .
02" (.5 mm).
4) Apply Three Bond (1212D) sealant to rocker cover sealing
surfaces before installation. See Fig. 6. Coat new "O" ring with oil,
and install on distributor adapter (if removed).
5) Coat camshaft area with oil before installing distributor
adapter. To complete installation, reverse removal procedure. Tighten
bolts to specification. See appropriate TORQUE SPECIFICATIONS table.
Removal (DOHC)
1) Remove UPPER INTAKE MANIFOLD and LOWER INTAKE MANIFOLD as
necessary. See UPPER INTAKE MANIFOLD and LOWER INTAKE MANIFOLD under
REMOVAL & INSTALLATION. Remove timing belt, camshaft sprockets and
rear timing belt covers. See TIMING BELT under REMOVAL & INSTALLATION.
2) Remove center cover and spark plug wires. Remove PCV and
breather hoses. Remove rocker covers and gaskets. Remove crank angle
sensor adapter. Remove front and rear camshaft bearing caps along with
seals and circular packings.
3) Remove remaining camshaft bearing caps in sequence: No. 2,
No. 4 and No. 3. Remove camshaft, rocker arms and lash adjusters. Mark
component location for reassembly reference.
Inspection (DOHC)
Inspect rocker arm for damaged roller and flaking. Inspect
camshaft for damage. Measure camshaft end play, journal diameter and
lobe height. Replace camshaft if it is not within specification. See
CAMSHAFT (DOHC) table in ENGINE SPECIFICATIONS at end of article.
Installation (DOHC)
1) Coat components with oil. Install lash adjusters and
rocker arms. Bring No. 1 cylinder to TDC. Ensure intake and exhaust
camshafts are installed correctly. Intake camshaft is marked with a
"V" and exhaust camshaft is marked with a "C" on hexagon section.
Position camshaft dowels as shown. See Fig. 21.
NOTE: If cylinder head is off vehicle, support cylinder head at
least .39" (10 mm) above work surface to prevent valve
damage while installing camshaft bearing caps.
Fig. 21: Installing Camshafts & Bearing Caps (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
2) Install camshaft bearing caps in sequence: No. 3, No. 4

and No. 2. Install bearing caps with front mark arrow facing the same
direction as similar mark on cylinder head beside bearing journal.
Note bearing cap number and identification mark ("I" for intake
camshaft and "E" for exhaust). See Fig. 22.
3) Install front and rear bearing caps. Tighten bearing cap
bolts to specification. See TORQUE SPECIFICATIONS (3000GT) table at
end of article. Coat camshaft oil seal area with oil. Using Seal
Installer (MD998761), install camshaft oil seal. Using Circular
Packing Installer (MD998761), install circular packing.
4) Install crankshaft angle sensor adapter. To complete
installation, reverse removal procedure. Tighten bolts to
specification. See TORQUE SPECIFICATIONS table.
REAR CRANKSHAFT OIL SEAL
Removal
Remove transaxle/transmission. See appropriate article in
TRANSMISSION SERVICING or CLUTCHES. Remove flywheel or drive plate.
Remove rear oil seal case. Pry seal from seal case.
Installation
To install, coat seal lip with oil. Using Seal Installer
(MD998718), install seal in seal case. Apply sealant to sealing
surface of seal case. Install seal case. Install flywheel or drive
plate. Tighten bolts to specification. See appropriate TORQUE
SPECIFICATIONS table at end of article. To complete installation,
reverse removal procedure.
WATER PUMP
Removal
Drain cooling system. Remove timing belt and crankshaft
sprocket. See TIMING BELT under REMOVAL & INSTALLATION. Remove coolant
pipes to water pump (if required). Remove water pump bolts, noting
length and location for reassembly reference. Remove water pump.
Installation
To install, reverse removal procedure using new gasket and
"O" rings. Coat all "O" rings with water before installation. Install
water pump and gasket. Tighten bolts to specification. See appropriate
TORQUE SPECIFICATIONS table at end of article.
OIL PAN
Removal (Montero)
1) Remove hood. Remove skid plate and lower covers. Raise and
support vehicle. Disconnect and remove exhaust pipe from exhaust
manifolds. Drain engine oil. Remove starter cover and starter. Remove
oil pressure sending unit connector. Remove front suspension
crossmember.
2) Remove transmission stays. Remove ground cable and motor
mount heat shields. Attach engine hoist. Remove motor mount bolts.
Raise engine, and insert a 1" wood spacer between front insulator and
mounts. Lower engine onto wood blocks.
3) Raise vehicle using a hoist. Remove oil pan bolts. Using
Seal Cutter (MD998727), separate oil pan from cylinder block. Remove
pan from vehicle.
Removal (Pickup)
1) Remove skid plate and lower covers. Raise and support
vehicle. Drain engine oil. Using Steering Linkage Puller (C-3894-A or
MB990635), disconnect relay rod from idler arm and steering box.
2) Remove oil pan bolts. Using Seal Cutter (MD998727),

separate oil pan from cylinder block. Remove pan from vehicle.
Removal (3000GT)
1) Raise and support vehicle. Remove engine undercovers.
Drain engine oil. Disconnect O2 sensor connector. Remove front exhaust
pipe from manifolds. On All-Wheel Drive (AWD) models, drain transfer
assembly. Remove front air dam. Remove AWD drive shaft and transfer
assembly.
2) On turbocharged models, remove oil return lines from oil
pan. On all models, remove starter. Remove crossmember and transaxle
stays. Remove bellhousing cover. Remove oil pan bolts. Using Seal
Cutter (MD998727), separate oil pan from cylinder block. Remove pan
from vehicle.
Inspection (All Models)
Clean sealant from oil pan mating surface on engine block and
oil pan. Check oil pan for cracks and damage. Check sealing surface
for damage and deformation. Inspect oil pick-up screen for damage.
Installation (All Models)
1) To install, reverse removal procedure. Apply sealant to
oil pan flange in a continuous .16" (4 mm) diameter bead. See Fig. 22.
Install oil pan within 15 minutes of applying sealant.
2) Tighten bolts to specification in proper sequence. See
appropriate TORQUE SPECIFICATIONS table at end of article. Wait at
least 30 minutes before adding oil and starting engine. On AWD models,
refill transfer assembly with GL-4 hypoid gear oil. On all models,
complete installation by reversing removal procedure.
Fig. 22: Sealant Application & Oil Pan Bolt Tightening Sequence
Courtesy of Mitsubishi Motor Sales of America, Inc.
OVERHAUL

CYLINDER HEAD
Check cylinder head height and warpage at gasket and manifold
surfaces. Resurface head if warpage exceeds specification. See
appropriate CYLINDER HEAD table under ENGINE SPECIFICATIONS at end of
article. Replace cylinder head if it is not within specification after
resurfacing.
VALVE SPRINGS
Measure free length of valve springs. Check spring pressure
at specified height. Replace springs if not within specification. See
appropriate VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS
at end of article. Check valve spring for squareness. Replace spring
if out-of-square exceeds 4 degrees.
NOTE: Install valve springs with enamel-coated side toward valve
spring retainer.
VALVE STEM OIL SEALS
With valves removed, remove oil seals from cylinder head.
Coat new seals with oil. Using Valve Stem Oil Seal Installer (MD998377
for Montero, MD998729 for Pick-up or MD998763 for DOHC), install valve
stem oil seal.
VALVE GUIDES
1) Measure valve stem-to-guide clearance. Replace valve guide
if not within specification. See appropriate VALVES & VALVE SPRINGS
table under ENGINE SPECIFICATIONS at end of article.
2) Using rod of Valve Guide Remover/Installer (MD998115) for\
SOHC, drive out valve guide toward combustion chamber side of cylinder
head. Note length of valve guides. On DOHC, use press and
appropriately-sized rod to press valve guide toward combustion chamber
side of head.
3) On all models, cylinder head must be bored to install
oversized valve guide once guide is removed. DO NOT install valve
guide of same dimension as old guide. Bore cylinder head to
specification for oversize valve guide. See appropriate OVERSIZE VALVE
GUIDE SPECIFICATIONS table.
4) On SOHC, install proper length valve guide. Intake guide
is 1.73" (43.9 mm) long and exhaust guide is 1.89" (48.0 mm) long. O\
n
all models, position cylinder head with combustion chamber downward.
5) Using valve guide remover/installer, install valve guide.
Remover/installer sets valve guide height on SOHC. On DOHC, install
valve guide to .689" (17.5 mm), measured from cylinder head spring
seating area to top of valve guide. On all models, ensure valve slides
smoothly in valve guide. Recondition valve seat.
OVERSIZE VALVE GUIDE SPECIFICATIONS TABLE (SOHC)









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Oversize In. (mm) Size Mark Bore Size In. (mm)
.002 (.05) ............ 5 ... .5138-.5145 (13.050-13.068)
.010 (.25) ............ 25 .. .5217-.5224 (13.251-13.269)
.020 (.51) ............ 50 .. .5315-.5322 (13.500-13.518)









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OVERSIZE VALVE GUIDE SPECIFICATIONS TABLE (DOHC)








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Oversize In. (mm) Size Mark Bore Size In. (mm)
.002 (.05) ............ 5 ... .4744-.4751 (12.050-12.068)
.010 (.25) ............ 25 .. .4823-.4830 (12.251-12.269)
.020 (.51) ............ 50 .. .4921-.4928 (12.500-12.518)









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VALVE SEAT (SOHC)
1) Valve seat sinkage should be checked after valve and valve
seat have been reconditioned and lightly lapped. With valve assembly
installed, measure installed height of valve spring between spring
seat and retainer. Valve seat must be replaced if measurement exceeds
1.63" (41.4 mm).
2) Grind seat wall thickness until seat can be removed.
Machine cylinder head to accommodate an oversize valve seat. See
OVERSIZE VALVE SEAT SPECIFICATIONS (SOHC) table. Heat cylinder head to\
approximately 480
F (250C), and install valve seat. Grind valve seat
using 45-degree stone. Use 30-degree and 60-degree stones to set seat
height.
OVERSIZE VALVE SEAT SPECIFICATIONS TABLE (SOHC)









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Application In. (mm)
Intake
Bore Depth
.012" (.3 mm) Oversize ............ .311-.319 (7.9-8.1)
.024" (.6 mm) Oversize ............ .323-.331 (8.2-8.4)
Bore Diameter
.012" (.3 mm) Oversize .. 1.7440-1.7451 (44.300-44.325)
.024" (.6 mm) Oversize .. 1.7559-1.7569 (44.600-44.625)
Exhaust
Bore Depth
.012" (.3 mm) Oversize ............ .311-.319 (7.9-8.1)
.024" (.6 mm) Oversize ............ .323-.331 (8.2-8.4)
Bore Diameter
.012" (.3 mm) Oversize .. 1.5079-1.5089 (38.300-38.325)
.024" (.6 mm) Oversize .. 1.5197-1.5207 (38.600-38.625)









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VALVE SEAT (DOHC)
Grind seat wall thickness until seat can be removed. Machine
cylinder head to accommodate an oversize valve seat. See OVERSIZE
VALVE SEAT SPECIFICATIONS (DOHC) table. Chill cylinder head with
liquid nitrogen, and install valve seat. Grind valve seat using 45-
degree stone. Use 30-degree and 60-degree stones to adjust seat
height.
OVERSIZE VALVE SEAT SPECIFICATIONS TABLE (DOHC)









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Application In. (mm)
Intake
Bore Depth
.012" (.3 mm) Oversize ............ .295-.303 (7.5-7.7)
.024" (.6 mm) Oversize ............ .307-.315 (7.8-8.0)
Bore Diameter
.012" (.3 mm) Oversize .. 1.4291-1.4301 (36.300-36.325)
.024" (.6 mm) Oversize .. 1.4409-1.4419 (36.600-36.625)
Exhaust
Bore Depth

.012" (.3 mm) Oversize ............ .311-.319 (7.9-8.1)
.024" (.6 mm) Oversize ............ .323-.331 (8.2-8.4)
Bore Diameter
.012" (.3 mm) Oversize .. 1.3110-1.3120 (33.300-33.325)
.024" (.6 mm) Oversize .. 1.3228-1.3238 (33.600-33.625)









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VALVES
Disassemble cylinder head. Measure valve stem diameter, valve
margin and overall length. Replace valves if not within specification.
See appropriate VALVES & VALVE SPRINGS table under ENGINE
SPECIFICATIONS at end of article. Check valve for worn valve tip.
Measure valve margin after grinding valves.
LASH ADJUSTERS
Before installation, submerge lash adjuster in diesel fuel.
Using a small wire, hold down internal check valve. Pump plunger up
and down 4 or 5 times to bleed air from lash adjuster.
CYLINDER BLOCK ASSEMBLY OVERHAUL
CYLINDER BLOCK
1) Inspect cylinder block for cracks, warpage, cylinder bore
taper and out-of-round. Replace or repair cylinder block if it is not
within specification. See CYLINDER BLOCK table under ENGINE
SPECIFICATIONS at end of article.
2) Measure cylinder bore and piston skirt diameter. Piston
skirt diameter should be measured at 90-degree angle to piston pin.
Clearance between piston and cylinder bore must be within
specification. See appropriate PISTONS, PINS & RINGS table under
ENGINE SPECIFICATIONS at end of article.
PISTON & ROD ASSEMBLY
1) Remove cylinder heads, and remove oil pan. See CYLINDER
HEADS and OIL PAN under REMOVAL & INSTALLATION. Ensure cylinder ridge
is removed. Mark connecting rod and cap for cylinder identification.
2) Note front mark on piston and connecting rod. See Fig. 23.
Mark is positioned toward timing belt side of engine. Remove rod cap
and piston assembly.
3) Ensure piston ring end gap and side clearance are within
specification. See appropriate PISTONS, PINS & RINGS table under
ENGINE SPECIFICATIONS at end of article. Install rings on piston with
ring code identification marks toward top of piston. On DOHC, top ring
is marked "T" and No. 2 ring is marked "T2". On SOHC, top ring is
marked "T1" and No. 2 ring is marked "2R". Lubricate piston, rings and
cylinder bore with engine oil.
4) Properly space ring end gaps on piston. See Fig. 23.
Install piston and rod into cylinder bore. Ensure piston is installed
with front mark toward timing belt side of engine.
NOTE: Front mark "R" on piston indicates installation in
cylinders No. 1, 3 or 5 while front mark "L" indicates
installation in cylinders No. 2, 4 or 6. Ensure front mark
on piston and connecting rod are toward timing belt side of
engine. See Fig. 23.
5) Check bearing clearance using Plastigage method. Tighten
rod cap nuts to specification. See appropriate TORQUE SPECIFICATIONS

table at end of article. Ensure rod moves freely on crankshaft. Check
connecting rod side play. Repair or replace connecting rod if not
within specification. See CONNECTING RODS table under ENGINE
SPECIFICATIONS at end of article.
Fig. 23: Aligning Piston & Rings
Courtesy of Mitsubishi Motor Sales of America, Inc.
FITTING PISTONS