1991 MITSUBISHI MONTERO height

Removal (SOHC)
1) Drain cooling system. Remove upper and lower intake
manifolds and brackets. See UPPER INTAKE MANIFOLD and LOWER INTAKE
MANIFOLD under REMOVAL & INSTALLATION. Remove spark plug wires. Remove
splash shields.
2) Disconnect O2 sensor. Disconnect exhaust pipe from exhaust
manifold, and support to crossmember using wire. Remove heat shields
and exhaust manifolds. See EXHAUST MANIFOLDS under REMOVAL &
INSTALLATION.
3) Remove distributor (left or rear head). Remove timing bel\
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outer covers, camshaft sprockets, timing belt and timing belt inner
covers. See TIMING BELT under REMOVAL & INSTALLATION. Remove accessory
bracket bolts from front of cylinder head. Remove rocker cover and
gasket.
4) Using Socket (MD998051), loosen cylinder head bolts in 2-\
3
steps using proper sequence. See Fig. 5. Remove cylinder head and
camshaft assemblies. Note direction of washer installation on head
bolts.
NOTE: Cylinder head bolts must be loosened in 2-3 steps using
proper sequence to prevent cylinder head warpage and
cracking.
Fig. 5: Cylinder Head Bolt Removal & Tightening Sequence
Courtesy of Mitsubishi Motor Sales of America, Inc.
Inspection (SOHC)
Check cylinder head height and warpage at gasket and manifold

TIMING BELT under REMOVAL & INSTALLATION. Remove intake camshaft
sprockets.
4) Remove coolant manifold and coolant inlet pipe. Using
Socket (MD998051), remove cylinder head bolts. Remove cylinder head
and camshaft assemblies. Note direction of washer installation on head
bolts.
Inspection (DOHC)
Check cylinder head height. Check warpage at gasket and
manifold surfaces. Resurface head if warpage exceeds specification.
See CYLINDER HEAD (DOHC) table under ENGINE SPECIFICATIONS at end of
article. After resurfacing, recheck cylinder head height. Replace
cylinder head if it is not within specification.
Installation (DOHC)
1) Ensure mating surfaces are clean and dry. Note
identification mark located on front of head gasket. Identification
marks are: "R" for SOHC, "2DN" for DOHC non-turbocharged and "2DT" for
DOHC turbocharged engine. Install head gasket with identification mark
toward timing belt side of engine and facing upward. Ensure all holes
are aligned.
NOTE: Install head gasket with identification mark toward timing
belt side of engine and facing upward. Ensure all holes
align. Install washers on head bolts with chamfered side
toward bolt head.
2) Install cylinder head and bolts. Ensure washers are
installed on head bolts with chamfered side toward bolt head. Using
proper sequence, tighten bolts to specification in 2-3 steps. See
Fig. 5 . See TORQUE SPECIFICATIONS (3000GT) table at end of article. On
turbocharger equipped engines, back off head bolts once, and repeat
tightening procedure.
3) To reinstall camshaft sprocket, hold hexagonal area of
camshaft using wrench while tightening sprocket bolt. Tighten rocker
cover bolts in a crisscross pattern. Start at 4 corners of rocker
cover and move toward center.
NOTE: Rocker cover bolts are color coded. Front cylinder bank
bolts are black; rear cylinder bank bolts are green.
4) To complete installation, reverse removal procedure.
Tighten bolts and nuts to specification. See TORQUE SPECIFICATIONS
(3000GT) table.
FRONT CRANKSHAFT OIL SEAL
Removal & Installation
Remove timing belt and crankshaft sprocket. See TIMING BELT
under REMOVAL & INSTALLATION. Pry oil seal from oil pump. To install,
coat seal lip with grease. Using Seal Installer (MD998717), install
seal in oil pump. Install remaining components. See appropriate TORQUE
SPECIFICATIONS table at end of article.
TIMING BELT
Removal (Montero & Pickup)
1) Drain cooling system. Disconnect upper radiator hose.
Remove upper radiator shroud. Remove cooling fan and fan clutch
assembly. Remove cooling fan pulley. Remove all drive belts. Remove
power steering pump with pressure and return hoses connected, and set
aside.
2) Remove power steering pump brackets. Remove A/C tensioner

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

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

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VALVES & VALVE SPRINGS SPECIFICATIONS (SOHC)
VALVES & VALVE SPRINGS TABLE (SOHC)








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Application Specification
Intake Valves
Face Angle ..................................... 45-45.5

Minimum Margin ........................... .028" (.71 mm)
Standard Length ...................... 4.055" (103.00 mm)
Stem Diameter ............. .3134-.3140" (7.960-7.976 mm)
Exhaust Valves
Face Angle ..................................... 45-45.5

Minimum Margin .......................... .059" (1.50 mm)
Standard Length ...................... 4.043" (102.70 mm)
Stem Diameter ............. .3122-.3130" (7.930-7.950 mm)
Valve Springs
Free Length
Standard ............................. 1.988" (50.50 mm)
Limit ................................ 1.949" (49.50 mm)
Installed Height ...................... 1.591" (40.41 mm)
Out-Of-Square
Standard ............................................ 2

Limit ............................................... 4
Lbs. @ In. (kg @ mm)
Pressure
Valve Closed ..................... [email protected] ([email protected])









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VALVES & VALVE SPRINGS SPECIFICATIONS (DOHC)
VALVES & VALVE SPRINGS TABLE (DOHC)








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Application Specification
Intake Valves
Face Angle ..................................... 45-45.5

Minimum Margin ........................... .019" (.48 mm)
Standard Length ...................... 4.185" (106.30 mm)
Stem Diameter ........................... .260" (6.60 mm)
Exhaust Valves
Face Angle ..................................... 45-45.5

Minimum Margin ........................... .039" (.99 mm)
Standard Length ...................... 4.150" (105.41 mm)
Stem Diameter ........................... .260" (6.60 mm)
Valve Springs
Free Length
Standard ............................. 1.846" (46.89 mm)
Limit ................................ 1.807" (45.90 mm)
Installed Height ...................... 1.492" (37.90 mm)
Out-Of-Square
Standard ............................................ 2

Limit ............................................... 4
Lbs. @ In. (kg @ mm)
Pressure
Valve Closed ..................... [email protected] ([email protected])









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CYLINDER HEAD SPECIFICATIONS (SOHC)
CYLINDER HEAD TABLE (SOHC)








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Application Specification
Cylinder Head Height ................... 3.307" (84.00 mm)
Maximum Warpage ........................... .008" (.20 mm)
Valve Seats (Intake & Exhaust)
Seat Angle ......................................... 45

Seat Width .................... .035-.051" (.90-1.30 mm)
Seat Bore Diameter ....... 1.732-1.742" (44.00-44.25 mm)
Valve Guides
Intake Valve
Valve Guide Cylinder Head
Bore I.D. ............. .5118-.5189" (13.00-13.18 mm)
Valve Guide Length ..................... 1.732" (44 mm)
Stem-To-Guide Clearance
Standard ................ .0012-.0024" (.030-.060 mm)
Limit ................................ .004" (.10 mm)
Exhaust Valve
Valve Guide Cylinder Head
Bore I.D. ............. .5118-.5189" (13.00-13.18 mm)
Valve Guide Length ..................... 1.890" (48 mm)
Stem-To-Guide Clearance
Standard ................ .0020-.0035" (.050-.090 mm)
Limit ................................ .006" (.15 mm)









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CYLINDER HEAD SPECIFICATIONS (DOHC)
CYLINDER HEAD TABLE (DOHC)








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Application Specification
Cylinder Head Height .................... 5.20" (132.1 mm)
Maximum Warpage ........................... .008" (.20 mm)
Valve Seats (Intake & Exhaust)
Seat Angle ......................................... 45

Seat Width .................... .035-.051" (.90-1.30 mm)
Seat Bore Diameter ....... 1.417-1.427" (35.99-36.25 mm)
Valve Guides
Intake Valve
Valve Guide Cylinder Head
Bore I.D. ............. .5118-.5189" (13.00-13.18 mm)
Valve Guide
Installed Height ................... .689" (17.50 mm)
Stem-To-Guide Clearance
Standard ................ .0008-.0020" (.020-.051 mm)
Limit .............................. .0039" (.099 mm)
Exhaust Valve
Valve Guide Cylinder Head
Bore I.D. ............. .5118-.5189" (13.00-13.18 mm)
Valve Guide
Installed Height ................... .689" (17.50 mm)
Valve Stem-To-Guide
Clearance
Standard ............... .0020-.0035" (.051-.089 mm)
Limit ............................. .0047" (.119 mm)









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CAMSHAFT SPECIFICATIONS (SOHC)