MITSUBISHI MONTERO 1991 Owner's Guide
Page 31 of 1333
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 PIN REPLACEMENT
1) Note reference mark on top of piston and connecting rod.
See Fig. 23 . Using press and Piston Pin Remover/Installer (MD998184
for SOHC or MD998765 for DOHC), remove pin.
2) Inspect piston for cracks and damage. Check ring side
clearance. Replace piston if not within specification. See appropriate
PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS.
3) Check connecting rod for bend and twist. Replace
connecting rod if twist exceeds .004" (.10 mm) or bend exceeds .002"
(.05 mm). Pressure required to install pin in rod is 1686-3934 lbs.
(7500-17,500 N).
4) Position piston on connecting rod. Ensure reference marks
on top of piston and connecting rod are aligned. See Fig. 23.
Lubricate all components with oil. To install, reverse removal
procedure. Ensure piston pin is centered in piston.
NOTE: Install piston with reference mark aligned with connecting
rod reference mark. See Fig. 23.
CRANKSHAFT & MAIN BEARINGS
1) Remove flywheel or drive plate. Remove
transaxle/transmission mounting plate and rear seal case. Remove oil
pump, oil pan and oil pick-up tube. Ensure connecting rods and main
bearing cap are marked for location.
2) Remove connecting rod caps and bearings. Note direction of
arrow on main bearing cap. Remove main bearing cap. See Fig. 24.
Ensure all components are placed in correct order. Remove crankshaft.
Remove main bearings from cylinder block. Mark bearings for location.
3) Inspect crankshaft for cracks and damaged gear or threads.
Check crankshaft for taper and out-of-round. Replace or repair
crankshaft if it is not within specification. See CRANKSHAFT, MAIN &
CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS at end of
article.
4) Install upper main bearings in cylinder block. Ensure oil
hole is aligned and bearing is properly seated. Lubricate bearings
with engine oil. Install thrust bearings on No. 3 main bearing journal
with oil grooves toward crankshaft thrust surface.
5) Install crankshaft in block. Install thrust bearing on No.
3 main bearing cap with oil grooves toward crankshaft thrust surface.
Install main bearing cap with arrow toward front of engine.
6) Check oil clearance using Plastigage method. Tighten bolts
to specification in proper sequence. See Fig. 24. See appropriate
TORQUE SPECIFICATIONS table at end of article. Remove main bearing
cap. Clearance must be within specification. See CRANKSHAFT, MAIN &
CONNECTING ROD BEARINGS table. If oil clearance exceeds specification,
replace bearings or crankshaft.
7) Ensure crankshaft rotates freely with main bearing cap
installed. Check crankshaft end play. See CRANKSHAFT, MAIN &
CONNECTING ROD BEARINGS table.
8) Install connecting rod caps and bearings. Ensure
components are installed in original location. Tighten rod nuts to
specification. See appropriate TORQUE SPECIFICATIONS table. Ensure
connecting rods move freely on crankshaft. To complete installation,
reverse removal procedure. Tighten bolts to specification.
Page 32 of 1333
Fig. 24: Main Bearing Cap Bolt Tightening Sequence
Courtesy of Mitsubishi Motor Sales of America, Inc.
CONNECTING ROD BEARINGS
1) Mark bearing cap and connecting rod for location. Remove
connecting rod cap and bearing. Install replacement bearing.
2) Ensure reference marks on rod cap and connecting rod are
aligned. Check bearing clearance using Plastigage method. Ensure
connecting rod moves freely on crankshaft. Check connecting rod side
play. See CONNECTING RODS table under ENGINE SPECIFICATIONS at end of
article.
CRANKSHAFT END PLAY
If end play is not within specification, inspect thrust
bearings and crankshaft. Replace thrust bearing or crankshaft to
obtain correct end play. See CRANKSHAFT, MAIN & CONNECTING ROD
BEARINGS table under ENGINE SPECIFICATIONS at end of article.
ENGINE OILING
ENGINE LUBRICATION SYSTEM
Oil pressure is provided by a rotor-type pump driven by
crankshaft. Pressure relief valve is located in oil pump body.
CRANKCASE CAPACITY
Montero & Pick-up oil capacity is 5.0 qts. (4.7L). Add .5 qt.\
(.4L) with filter replacement. Add .5 qt. (.4L) with oil cooler.
3000GT oil capacity is 4.2 qts. (4.0L). Add .5 qt. (.4L) with filter\
replacement. Add .5 qt. (.4L) with oil cooler.
Page 33 of 1333
OIL PRESSURE
Oil pressure should be at least 11.4 psi (.8 kg/cm) at idle
and engine oil temperature of 167-194F (75-90C).
OIL PUMP
Removal
Remove timing belt and crankshaft sprocket. See TIMING BELT
under REMOVAL & INSTALLATION. Remove oil pan. See OIL PAN under
REMOVAL & INSTALLATION. Remove oil filter and mounting bracket. Remove
oil pump and gasket from cylinder block. Note bolt length and location
for installation.
Disassembly & Inspection
1) Disassemble pump, and check for scoring and cracks.
Install rotors in pump body. Check clearance between driven rotor and
pump body. See OIL PUMP SPECIFICATIONS table. Place straightedge
across pump body to check rotor side clearance.
2) Check clearance between straightedge and both rotors.
Replace rotor set or pump assembly if not within specification. Ensure
relief valve slides freely in pump body bore. Inspect relief valve
spring for damage.
OIL PUMP SPECIFICATIONS TABLE
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Application In. (mm)
Driven Rotor-To-Pump Body ........ .0039-.0071 (.099-.180)
Rotor Side Clearance ............. .0016-.0037 (.041-.094)
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Reassembly & Installation
1) Reassemble pump. Tighten pump rear cover bolts to
specification. See appropriate TORQUE SPECIFICATIONS table in this
article. Install oil pump and gasket. Ensure splined teeth of oil pump
align with crankshaft. Install bolts, and tighten to specification.
2) If oil seal was removed, coat new seal with grease. Using
Seal Installer (MD998717), install seal in oil pump until flush with
case. Install remaining components.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE (MONTERO & PICKUP) \
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Application Ft. Lbs. (N.m)
Air Intake Plenum Stay Bolts ............... 11-14 (15-19)
Camshaft Bearing Cap Bolt .................. 14-15 (19-20)
Camshaft Sprocket Bolt ..................... 58-72 (79-98)
Connecting Rod Nut ......................... 37-38 (50-52)
Crankshaft Pulley Bolt
Montero .............................. 108-116 (146-157)
Pickup ............................... 130-137 (176-186)
Cylinder Head Bolt ( 1)
Cold Engine .............................. 65-72 (88-98)
Drive Plate Bolt ........................... 53-55 (72-75)
Exhaust Manifold Nut ....................... 11-16 (15-22)
Flywheel Bolt .............................. 53-55 (72-75)
Intake Manifold Bolts ...................... 11-15 (15-20)
Left Engine Support Bracket Bolt ........... 15-21 (20-30)
Page 34 of 1333
Main Bearing Cap Bolt ...................... 55-61 (75-83)
Oil Pick-Up Tube Bolt ...................... 11-15 (15-20)
Rear Engine Support
Bracket-To-Engine Bolt .................... 13-18 (18-25)
Relief Valve Plug .......................... 29-36 (39-49)
Right Engine Support Bracket Bolt
10x22 mm ................................. 25-36 (34-49)
12x22 mm & 12x32 mm ...................... 47-61 (64-83)
Rocker Shaft ............................... 14-15 (19-20)
Timing Belt Tensioner Bolt ................. 16-21 (22-29)
Water Pump Bolt ............................ 14-20 (19-27)
INCH Lbs. (N.m)
Delivery Pipe Bolt ......................... 84-108 (9-12)
Distributor Adapter Bolt .................. 108-132 (12-15)
Oil Filter Bracket Bolt .................. 108-120 (12-14)
Oil Pan Bolt ................................. 48-60 (5-7)
Oil Pump Cover Bolt ........................ 72-108 (8-12)
Oil Pump Mounting Bolt ................... 108-120 (12-14)
Rear Seal Case Bolt ........................ 84-108 (9-12)
Rocker Cover Bolt ............................ 72-84 (8-9)
Throttle Body Bolt ......................... 84-108 (9-12)
Timing Belt Cover Bolt ..................... 84-108 (9-12)
Transmission Mounting Plate Bolt ........... 84-108 (9-12)
( 1) - Tighten in 2 steps using proper sequence.
See Fig. 4.
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TORQUE SPECIFICATIONS TABLE (3000GT) \
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Application Ft. Lbs. (N.m)
Air Intake Plenum Stay Bolts ..................... 13 (18)
Automatic Tensioner Bolt ......................... 17 (23)
Camshaft Bearing Cap Bolt ........................ 15 (20)
Camshaft Sprocket Bolt ........................... 65 (88)
Connecting Rod Nut ............................... 38 (52)
Crankshaft Pulley Bolt
SOHC ................................. 108-116 (146-157)
DOHC ................................. 130-137 (176-186)
Cylinder Head Bolt ( 1)
SOHC ................................... 76-83 (103-113)
DOHC
Non-Turbo ............................. 76-83 (103-113)
Turbo ................................. 87-94 (118-127)
Distributor Adapter Bolt ......................... 11 (15)
Drive Plate Bolt ................................. 55 (75)
Engine Support Bracket Bolt
Except 10x40 mm ........................ 76-83 (103-113)
10x40 mm ................................. 47-54 (63-73)
Exhaust Manifold Nut ............................. 13 (18)
Flywheel Bolt .................................... 55 (75)
Intake Manifold Bolt
Lower Manifold
Non-Turbo ............................... 11-15 (15-20)
Turbo .................................... 9-11 (12-15)
Upper Manifold ................................. 13 (18)
Main Bearing Cap Bolt ............................ 58 (79)
Oil Filter Bracket Bolt .......................... 11 (15)
Oil Pick-Up Tube Bolt ............................ 14 (19)
Oil Pump Mounting Bolt ........................... 11 (15)
Page 35 of 1333
Rear Engine Support
Bracket-To-Engine Bolt .................... 13-18 (18-25)
Relief Valve Plug ................................ 33 (45)
Rocker Shaft ............................... 14-15 (19-20)
Roll Stopper Bracket Through Bolts ......... 36-43 (49-58)
Turbocharger-To-Exhaust Fitting ............ 40-47 (54-64)
Timing Belt Tensioner Bolt ....................... 31 (42)
Water Pump Bolt .................................. 17 (23)
INCH Lbs. (N.m)
Delivery Pipe Bolt .............................. 108 (12)
Oil Pan Bolt ................................. 48-60 (5-7)
Oil Pump Cover Bolt .............................. 96 (11)
Rear Seal Case Bolt .............................. 96 (11)
Rocker Cover Bolt
SOHC ....................................... 72-84 (8-9)
DOHC ............................................ 26 (3)
Throttle Body Bolt ......................... 84-108 (9-12)
Timing Belt Cover Bolt ..................... 84-108 (9-12)
Transmission Mounting Plate Bolt ........... 84-108 (9-12)
( 1) - Tighten in 2 steps using proper sequence.
See Fig. 4.
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ENGINE SPECIFICATIONS
GENERAL ENGINE SPECIFICATIONS
GENERAL SPECIFICATIONS TABLE \
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Application Specification
3.0L V6 DOHC Non-Turbo
Displacement ....................... 181.4 Cu. In. (3.0L)
Bore ................................... 3.587" (91.1 mm)
Stroke ................................. 2.992" (76.0 mm)
Compression Ratio ................................ 10.0:1
Fuel System ......................................... PFI
Horsepower @ RPM ............................. 222 @ 6000
Torque Ft. Lbs. @ RPM ........................ 201 @ 4500
3.0L V6 DOHC Turbo
Displacement ....................... 181.4 Cu. In. (3.0L)
Bore ................................... 3.587" (91.1 mm)
Stroke ................................. 2.992" (76.0 mm)
Compression Ratio ................................. 8.0:1
Fuel System ......................................... PFI
Horsepower @ RPM ............................. 300 @ 6000
Torque Ft. Lbs. @ RPM ........................ 307 @ 2500
3.0L V6 SOHC
Displacement ....................... 181.4 Cu. In. (3.0L)
Bore ................................... 3.587" (91.1 mm)
Stroke ................................. 2.992" (76.0 mm)
Compression Ratio ................................. 8.9:1
Fuel System ......................................... PFI
Horsepower @ RPM ............................. 143 @ 5000
Torque Ft. Lbs. @ RPM ........................ 168 @ 2500
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Page 36 of 1333
CRANKSHAFT, MAIN & CONNECTING
ROD BEARINGS SPECIFICATIONS
CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS TABLE
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Application In. (mm)
Crankshaft
End Play
Standard ...................... .0020-.0098 (.050-.250)
Limit ...................................... .012 (.30)
Main Bearings
Journal Diameter ........................... 2.36 (59.9)
Journal Out-Of-Round
SOHC ..................................... .0002 (.005)
DOHC .................................... .00012 (.003)
Journal Taper ............................. .0002 (.005)
Oil Clearance
Standard
SOHC ........................ .0008-.0019 (.020-.048)
DOHC ........................ .0007-.0017 (.018-.043)
Limit ...................................... .004 (.10)
Connecting Rod Bearings
Journal Diameter ......................... 1.965 (49.91)
Journal Out-Of-Round
SOHC ..................................... .0002 (.005)
DOHC .................................... .00012 (.003)
Journal Taper ............................. .0002 (.005)
Oil Clearance
Standard ...................... .0006-.0018 (.015-.046)
Limit ...................................... .004 (.10)
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CONNECTING RODS SPECIFICATIONS
CONNECTING RODS TABLE \
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Application In. (mm)
Maximum Bend .................................. .002 (.05)
Maximum Twist (Total Rod Length) .............. .004 (.10)
Side Play
Standard ....................... .0039-.0099 (.099-.251)
Limit ....................................... .016 (.41)
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PISTONS, PINS & RINGS SPECIFICATIONS (SOHC)
PISTONS, PINS & RINGS TABLE (SOHC) \
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Application In. (mm)
Pistons
Clearance ...................... .0008-.0016 (.020-.040)
Diameter ................................. 3.587 (91.11)
Pins
Piston Fit ......................................... ( 1)
Rod Fit ............................................ ( 2)
Rings
No. 1
End Gap
Standard .................... .0118-.0177 (.300-.450)
Limit .................................... .031 (.79)
Page 37 of 1333
Side Clearance
Standard .................... .0020-.0035 (.051-.089)
Limit .................................... .004 (.10)
No. 2
End Gap
Standard .................... .0098-.0157 (.249-.399)
Limit .................................... .031 (.79)
Side Clearance
Standard .................... .0008-.0024 (.020-.060)
Limit .................................... .004 (.10)
No. 3 (Oil)
End Gap
Standard ........................ .008-.024 (.20-.60)
Limit .................................... .039 (.99)
(1) - Slip.
( 2) - At press load of 1686-3934 lbs. (7500-17500 N).
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PISTONS, PINS & RINGS SPECIFICATIONS (DOHC)
PISTONS, PINS & RINGS TABLE (DOHC) \
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Application In. (mm)
Pistons
Clearance ...................... .0012-.0020 (.030-.051)
Diameter ................................. 3.587 (91.11)
Pins
Piston Fit ......................................... ( 1)
Rod Fit ............................................ ( 2)
Rings
No. 1
End Gap ....................... .0118-.0177 (.300-.450)
Side Clearance
Standard .................... .0012-.0028 (.030-.071)
Limit .................................... .004 (.10)
No. 2
End Gap ....................... .0177-.0236 (.450-.599)
Side Clearance
Standard .................... .0008-.0024 (.020-.060)
Limit .................................... .004 (.10)
No. 3 (Oil)
End Gap
Standard ........................ .008-.024 (.20-.60)
Limit .................................... .039 (.99)
( 1) - Slip.
( 2) - At press load of 1686-3934 lbs. (7500-17500 N).
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CYLINDER BLOCK SPECIFICATIONS
CYLINDER BLOCK TABLE \
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Application In. (mm)
Cylinder Bore
Standard Diameter ......................... 3.586 (91.10)
Maximum Taper & Out-Of-Round ............... .0008 (.020)
Maximum Deck Warpage
Standard ..................................... .002 (.05)
Limit ...................................... .0039 (.099)
Page 38 of 1333
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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 ..................... 74@1.591 (33.6@40.41)
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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 ..................... 62@1.492 (28.1@37.90)
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Page 39 of 1333
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)
Page 40 of 1333
CAMSHAFT TABLE (SOHC) \
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Application In. (mm)
End Play
Standard ........................... .004-.008 (0.1-0.2)
Limit ....................................... .015 (0.4)
Journal Diameter ............................. 1.34 (34.0)
Lobe Height
Standard ................................. 1.624 (41.25)
Limit .................................... 1.604 (40.75)
Oil Clearance .................... .0020-.0035 (.050-.090)
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CAMSHAFT SPECIFICATIONS (DOHC)
CAMSHAFT TABLE (DOHC) \
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Application In. (mm)
End Play
Standard ........................... .004-.008 (0.1-0.2)
Limit ....................................... .015 (0.4)
Journal Diameter ............................ 1.024 (26.0)
Lobe Height
Intake
Standard ................................ 1.397 (35.49)
Limit ................................... 1.378 (34.99)
Exhaust
Standard ................................ 1.386 (35.20)
Limit ................................... 1.366 (34.70)
Oil Clearance .................... .0020-.0035 (.050-.090)
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