| The following technical bulletins were published by AERA. |
| | CYLINDER HEAD BOLT TORQUE FOR 4 & 6 G MITSUBISHI ENGINES | Cylinder Head Bolt Tightening Caution For
1992-1996 Mitsubishi 4G & 6G Series Engines
The AERA Technical Committee offers the following information regarding cylinder head bolt tightening caution on 1992-1996 Mitsubishi 4G & 6G series engines. Information previously published in the OEM service manuals was incorrect and the following specifications should be used.
Installing non-elastic head bolts use the following torque values for vehicles/engine.
For torque sequence see Figure 1 to tighten in three steps use the bolt tightening sequence, if applicable. Refer to sequence chart. Note: Designations such as Turbo, Non-Turbo, SOHC and DOHC are only used if these items cause variations to the torque information of the engine.
Years Models Engine Torque
1992-95 Mirage thru May 1995 4G1 / 1.5L 53 ft/lbs (73 Nm)
1992-94 Eclipse 4G3 / 1.8L 53 ft/lbs (73 Nm)
1992 Eclipse, Galant 4G6 / 2.0L 80 ft/lbs (108 Nm) DOHC
1992 Galant, Expo & Truck 4G6 / 2.4L 80 ft/lbs (108 Nm) SOHC
1995 Galant 4G6 / 2.5L 80 ft/lbs (108 Nm) SOHC
1992-95 Truck, Montero, Galant 6G7 / 3.0L 80 ft/lbs (108 Nm) SOHC
& Diamante
1993-95 Diamante Wagon 6G7 / 3.0L 80 ft/lbs (108 Nm) SOHC
1992-95 Diamante & 3000 GT 6G7 / 3.5L 80 ft/lbs (108 N m) DOHC non-Turbo
1992-95 3000 GT 6G7 / 3.0L 91 ft/lbs (123 N m) DOHC Turbo *
* Loosen all bolts and retighten to 91 ft/lbs.
1994-95 Montero 6G7 / 3.5L 80 ft/lbs (108 N m) DOHC Turbo
Figure 1. Cylinder Head bolt torque Sequence
Installing Elastic Head Bolts (plastic-angle tightening method).
Before reusing head bolts measure the shank lengths of ALL the head bearing bolts, if measurement of (see below) exceeded or the bolt has visual damage REPLACE THE BOLTS. Measure from the tip to the shoulder under the bolt head (not to the shoulder of the washer). See Figure 2
1995-96 Mirage after 5/95 4G9 / 1.5L ** 4.063" (103.200 MM) SOHC 16Valve
1993-96 Mirage 4G9 / 1.8L *** 3.795" (96.400 MM) SOHC 8Valve
1992-95 Expo LRV 4G9 / 1.8L 3.795" (96.400 MM) SOHC 8Valve
1993-96 Eclipse 4G6 / 2.0L 3.913" (99.400 MM) S & D 16 Valve 1993 Galant 4G6 / 2.0L 3.913" (99.400 MM) S & D 16 Valve
1993-95 Expo, Expo LRV & Truck 4G6 / 2.4L 4.740" (120.400 MM) SOHC 8 Valve
1994-96 Galant 4G6 / 2.4L 4.740" (120.400 MM) SOHC 8 Valve
Figure 2. Cylinder Head Bolt Shank Measurement
For torque sequence see Figure 3 to tighten elastic head bolts using the plastic/angle tightening method; the following procedure is applicable to all the engines listed below.
Step 1; Torque all bolts (in sequence) to specification 58 ft/lbs (78 Nm). ***
Step 2, Loosen all bolts fully.
Step 3, Tighten all bolts to 14 ft/lbs (20 Nm).
Step 4, Tighten using a breaker bar (not a torque wrench) 90° rotation.
Step 5, Repeat step four.
Note: ** For the 1995-96 Mirage after 5/95 initial torque is a lower value Step one Torque all bolts (in sequence) to specification 34 ft/lbs (49 Nm).
*** For the 1993-96 Mirage & 1992-95 Expo LRV initial torque is a lower value Step one Torque all bolts (in sequence) to specification 54 ft/lbs (74 Nm).
Figure 2. Cylinder Head Bolt Shank Measurement
Figure 3. Cylinder Head Bolt Torque Sequence.
The AERA Technical Committee | | MAIN BEARING BOLT TORQUE CAUTION ON MITSUBISHI 4/6 G ENGINES | Main Bolt Tightening Caution For
1992-1999 Mitsubishi 4G & 6G Series Engines
The AERA Technical Committee offers the following information for main bolt tightening caution on 1992-1995 Mitsubishi 4G & 6G series engines. Information previously published in the OEM service manuals was incorrect and the following specifications should be used. The information in TB 2039 has abeen updated and it should be destroyed, as it is no longer valid information.
To install non-elastic main bearing bolts, the following procedure is applicable to all vehicles/engine listed below.
Tighten the bolts on each main bearing cap equally until the specified torque is achieved. Use the bolt-tightening sequence shown in Figure 1 if applicable.
Years Models Engine Torque
1992-95 Mirage 4G1/1.5L 38 ft/lbs (53 Nm)
1992-94 Eclipse 4G3/1.8L 38 ft/lbs (53 Nm)
1992 Galant, Expo & Truck 4G6/2.0&2.4L 38 ft/lbs (53 Nm) SOHC
1992 Eclipse, Galant 4G6/2.0L 49 ft/lbs (68 Nm) DOHC
1992-95 Truck,Montero,Galant,
Diamante 6G7/3.0L 57 ft/lbs (79 Nm) SOHC
1993-95 Diamante Wagon 6G7/3.0L 57 ft/lbs (79 Nm) SOHC
1992-95 Diamante & 3000 GT 6G7/3.0L 67 ft/lbs (93 Nm) DOHC Non/Turbo
1992 3000 GT 6G7/3.0L 67 ft/lbs (93 Nm) DOHC Turbo
1993-95 3000 GT 6G7/3.0L 54 ft/lbs (74 Nm) DOHC Turbo
1994-95 Montero 6G7/3.5L 54 ft/lbs (74 Nm) DOHC Turbo
Elastic main bolt tightening (plastic-angle tightening method). Before reusing main bolts measure the shank lengths of ALL the main bearing bolts. If the measurement of 2.799 (71.100 MM) is exceeded or the bolt has visual damage REPLACE THE BOLTS. Measure from the tip to the shoulder under the bolt head (not to the shoulder of the washer) see figure 3.
To tighten elastic main bearing bolts using the plastic/angle tightening method; the following procedure is applicable to all the engines listed below.
1. Torque bolts (in sequence see figure 2) to specification 18 ft/lbs.
2. Using a breaker bar (not a torque wrench), tighten each bolt 90°.
3. Using a breaker bar (not a torque wrench), turn each bolt an additional 90°.
The following vehicles/engines use elastic main bearing bolts:
1993-95 Mirage 4G9/1.8L 18 ft/lbs (25 Nm) Plus 90°, +90°
1992-95 Expo LRV 4G9/1.8L 18 ft/lbs (25 Nm) Plus 90°, +90°
1993-95 Eclipse 4G6/2.0L 18 ft/lbs (25 Nm) Plus 90°, +90°
1993 Galant 4G6/2.0L 18 ft/lbs (25 Nm) Plus 90°, +90°
1993-95 Expo, Expo LRV,
Truck 4G6/2.4L 18 ft/lbs (25 Nm) Plus 90°, +90°
1994-95 Galant 4G6/2.4L 18 ft/lbs (25 Nm) Plus 90°, +90°
The AERA Technical Committee | | CONNECTING ROD NUT TORQUE CAUTION | Connecting Rod Nut Tightening Caution On
1992-1995 Mitsubishi 4G Series & 6G7 Engines
The AERA Technical Committee offers the following information for connecting rod nut tightening caution on 1992-1995 Mitsubishi 4G Series & 6G7 engines. Information previously published in service manuals was incorrect and the following specifications should be used.
Years Models Engine Torque
1992-95 Mirage 4G1 14 FT/LBS (20 Nm) plus 90°
1992-94 Eclipse 4G3 25 FT/LBS (34 Nm)
1992 Eclipse, Galant, Mirage 4G6 38 FT/LBS (52 Nm)
Expo & Truck
1993-95 Eclipse, Galant, Mirage 4G6 14 FT/LBS (20 Nm) plus 90°
Expo LRV and Truck
1993-95 Mirage 4G9 14 FT/LBS (20 Nm) plus 90°
1992-95 Expo LRV
1992-96 Truck, Diamante (wagon) 6G72 38 FT/LBS
3000 GT, Montero & Galant
1992-95 Truck, Diamante (wagon) 6G74 25 FT/LBS (34 Nm) plus 90°
3000 GT, Montero & Galant
Note: If the above listed specifications are not used, engine failure may occur.
The AERA Technical Committee | | CRANKSHAFT THRUST BEARING CHANGES FOR 2.0 & 2.4L ENGINES | Crankshaft Thrust Bearing Changes For
Mitsubishi 2.0L 4G63 Turbo And 2.4L 4G64 Engines
The AERA Technical Committee offers the following information on crankshaft thrust bearing changes for Mitsubishi 2.0L DOHC 4G63 Turbo and 2.4L SOHC 4G64 engines.
Due to the changes in the crankshaft center bearing, the crankshaft bearing selection procedure for the affected vehicles has been changed. This new procedure will supersede all previous manuals.
Vehicles affected 1996-97 Galant 2.4L SOHC 4G64, 1996-97 Eclipse and Eclipse Spyder equipped with 2.0L DOHC 4G63 turbocharged engine and 1997 Montero Sport 2.4L SOHC 4G64 engines. See Figure 1. Below.
Install the main bearings as follows;
Install the bearings having an oil groove into the cylinder block.
The positions 1, 2, 4 and 5 upper block side bearing shells are grooved.
The number 3 position thrust now uses grooveless upper and lower bearing shells.
Install the bearings having NO oil groove into the bearing caps.
The positions 1, 2, 4 and 5 lower side bearing shells are grooveless.
The AERA Technical Committee | | EXCESSIVE OIL CONSUMPTION | Excessive Oil Consumption
on 1978-89 Chrysler Jet Valve Engines
AERA members have reported excessive oil consumption and spark plug fouling complaints on 1978-89 Chrysler jet valve engines. These engines are manufactured for Chrysler Corporation by Mitsubishi Motor Corporation of Japan.
There are several possibilities for allowing oil to pass into the combustion chamber. They are oil leaking past the valve stem seal or the jet valve body O-ring, or a worn jet valve body or valve stem. Since oil can travel among the various air passages in the cylinder head casting, it is important to inspect all jet valves not just the cylinder that is indicated by a fouled spark plug.
Remove the jet valve assembly as indicated in the appropriate service manual and inspect the O-ring for nicks, cuts, tears or deformation. Likewise, a brittle O-ring is not capable of sealing out lubricating oil. The O-ring, Chrysler part #MD009786, should be replaced whenever the jet valve assembly is removed from the cylinder head.
Disassemble the jet valve assembly and inspect the valve stem seal for damage or deformation. Chrysler recommends replacement of the complete assembly if the valve body or valve stem are worn. Use Chrysler part #MD009440.
Any oil residue or carbon must be removed from the jet valve passages before assembly. See the appropriate OE or aftermarket manual for further information and torque values.
The AERA Technical Committee | | VALVE STEM SEAL IDENTIFCATION ON MITSUBISHI 3.0L ENGINES | Valve Stem Seal Identification On
2000-02 Mitsubishi 3.0L VIN H Engines
AERA members have reported a difficulty correctly identifying valve stem seals on 2000-02 Mitsubishi VIN H engines. To properly identify the two different valve stem seals, Mitsubishi has color-coded the seals.
Upon removing the valve seals from the packaging, there may not be any identification sheet with the seals. This leaves the machinist wondering which seal goes on the intake valve and which one on the exhaust valve. To correctly install these seals, the one with charcoal gray identification color goes on the exhaust and the one with the green identification color goes on the intake.
Color Location Part #
Charcoal Gray Exhaust MD184303
Green Intake MD307342
AERA is currently unaware of an aftermarket supplier of the valve stem seals mentioned above.
The AERA Technical Committee | | BURNED JET VALVES | Burned Jet Valves On
Chrysler (Mitsubishi) 2.6L Engines
The AERA Technical Committee offers the following consideration for Chrysler 2.6L engines with repeated jet valve burning problems. This problem is most prevalent with engines that utilize hydraulic lash compensators (HLC). Reported failures have usually been shortly after cylinder head installation or
compensators replacement.
Unless the jet valves are readjusted after the engine has reached operating temperature, improper clearances will result. The correct lash adjustment of .010 (.254mm) can only be achieved of the HLC plunger is in its operating location. If the jet valve is adjusted before that point, or on the bench, operating oil pressure will change the previous clearance. Insufficient clearance may hold the jet valve off the seat and eventually burn it.
The AERA Technical Committee | | REVISED CRANK ON 92-96 2.0L ENGINES | Revised Crankshaft On
1992-96 Mitsubishi 2.0L Engines
AREA members have reported a revised crankshaft on 1992-96 Mitsubishi 2.0L engines. The area of revision is the thrust width and flywheel flange. At first glance, the crankshaft would appear to be the same as previous crankshafts.
Modification to the thrust area of the crankshaft involved reducing the length by approximately .130 (3.302 mm). The number of flywheel mounting bolt holes was also increased from six, to seven. It also appears, that the length of all other main bearing journals has been reduced slightly.
Years Used Thrust Length Number Of Rear Bolt Holes
1983-91 1.144 (29.58 mm) 6
1992-96 1.013 (25.53 mm) 7
Currently, main bearings sets are only available from Mitsubishi.
The AERA Technical Committee |
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