Cylinder Head and Valves
CYLINDER HEAD AND VALVESREMOVAL AND INSTALLATION
Removal Steps 1-21:
Required Special Tools:
^ MD998735: Valve Spring Compressor
^ MB992089: Retainer Holder
^ MB992085: Valve Stem Seal Pliers
^ MD998737: Valve Stem Seal Installer
REMOVAL SERVICE POINTS
[A] RETAINER LOCK REMOVAL
CAUTION:
Be careful not to allow retainer holder C to interfere with the wall of the tappet hole and to damage it.
Use a special tool MD998735 and MB992089 to compress the valve spring and to remove the retainer lock.
NOTE: Store removed parts such as valves and springs with tags describing cylinder No. and installed position attached for reassembly.
[B] VALVE STEM SEAL REMOVAL
Use special tool MB992085 to firmly pinch the base (larger external shape) of the stem seal and twist it right and left for pulling out.
INSTALLATION SERVICE POINTS
[A] VALVE STEM SEAL INSTALLATION
CAUTION:
^ The valve stem seal must not be reused.
^ Do not damage the tappet wall during assembly.
^ Be sure to use a special tool to install the valve stem seal. Poor installation causes oil loss via valve guides.
^ If oil is not applied, the valve stem seal may rise to the surface after it is press fitted.
1. Apply a thin coat of engine oil to a new valve stem seal.
2. Use special tool MD998737 to press fit the valve stem seal into the valve guide with the valve stem used as a guide.
[B] VALVE SPRING INSTALLATION
Install the valve spring so that the painted side faces toward the camshaft.
[C] RETAINER LOCK INSTALLATION
Use a special tool MD998735 and MB992089 to compress the valve spring and to install the retainer lock.
[D] CYLINDER HEAD GASKET / CYLINDER HEAD ASSEMBLY INSTALLATION
1. Completely remove the liquid gasket on the upper plane of the cylinder block and the lower plane of the cylinder head.
CAUTION:
Sufficiently check that there is no residual oil on the place where degreasing is performed. If fingerprints are left, do not touch it with bare hands after the degreasing, since the oils from your fingers will harm the seal ability.
2. Degrease the place specified in the illustration.
3. As shown in the illustration, apply a diameter 2.0 to 3.0 mm (0.08 to 0.12 inch) of sealant (Three bond 1217G [Mitsubishi Part No.1000A923] or equivalent) to the top face of cylinder block.
4. Install the cylinder head gasket.
NOTE: Check that the center of the liquid gasket is located toward the cylinder gasket in the position specified in the illustration.
5. As shown in the illustration, apply a diameter 2.0 to 3.0 mm (0.08 to 0.12 inch) of sealant (Three bond 1217G [Mitsubishi Part No.1000A923] or equivalent) to the top face of cylinder head gasket.
6. Install the cylinder head assembly.
[E] CYLINDER HEAD BOLT INSTALLATION
1. Install new cylinder head bolts and washers in the following procedure.
NOTE: Cylinder head bolts and washers must not be reused.
2. Apply an appropriate amount of engine oil to top and bottom surfaces of washers and threaded portion of bolts.
3. Install cylinder head bolts to the cylinder head.
NOTE: Bolts and washers are different parts for bolts on the timing chain side.
4. Tighten cylinder head bolts in several steps to the specified torque according to the assembly order shown.
Specified torque: 35 ± 2 Nm (26 ± 1 ft-lb)
5. Put a paint mark on all of cylinder head bolt heads and cylinder head.
CAUTION:
^ When the tightening angle is smaller than the specified tightening angle, the appropriate tightening capacity cannot be secured.
^ When the tightening angle is larger than the specified tightening angle, remove the bolt to start from the beginning again according to the procedure.
6. Tighten the cylinder head 90 degrees according to the tightening order.
Tighten it further 90 degrees and make sure that the paint mark on the cylinder head bolt is in a straight line with that on the cylinder head.
INSPECTION
CYLINDER HEAD
1. Check the cylinder head for water leakage, gas leakage, damage or cracks before cleaning.
2. Completely remove oil, scale, sealant, carbon, etc. After cleaning oil passages, blow air to make sure that they are not clogged.
CAUTION:
The grinding limit shall be within 0.2 mm (0.01 inch) in combination with the cylinder block to be assembled.
3. For the flatness on the cylinder head bottom, measure distortion using a straight edge and thickness gauge. If the distortion exceeds the limit, grind and repair it.
Distortion on bottom
Standard value: Within 0.05 mm (0.002 inch)
Limit: 0.2 mm (0.01 inch)
Grinding limit: 0.2 mm (0.01 inch)
Cylinder head height: 128.5 mm (5.06 inches)
VALVE
1. Repair the valve seat if contact with the valve seat is poor, uneven or broken.
2. Measure the margin. If the limit is exceeded, replace the valve.
Standard value:
Intake 1.022 mm (0.0402 inch)
Exhaust 1.094 mm (0.0431 inch)
Limit:
Intake 0.522 mm (0.0206 inch)
Exhaust 0.594 mm (0.0234 inch)
3. Measure overall length of the valve. If the limit is exceeded, replace the valve.
Standard value:
Intake 113.18 mm (4.456 inches)
Exhaust 105.89 mm (4.169 inches)
Limit:
Intake 112.68 mm (4.436 inches)
Exhaust 105.39 mm (4.149 inches)
VALVE SPRING
1. Measure free height of the spring.
If the limit is exceeded, replace the spring.
Standard value: 51.5 mm (2.03 inch)
Limit: 51.0 mm (2.01 inch)
2. Measure squareness of the spring. If the inclination exceeds the limit, replace the spring.
Standard value: 2 degrees or less
Limit: 4 degrees
VALVE GUIDE
Measure clearance between the valve guide and valve stem. If the clearance exceeds the limit, replace the valve guide or valve, or both.
Standard value:
Intake 0.020 -0.047 mm (0.0008 -0.0019 inch)
Exhaust 0.030 -0.057 mm (0.0012 -0.0022 inch)
Limit:
Intake 0.10 mm (0.004 inch)
Exhaust 0.15 mm (0.006 inch)
VALVE SEAT
Assemble the valve, then measure the contact width. If the measurement exceeds the specified limit, replace the valve seat.
Standard value
Intake: 1.16 -1.46 mm (0.046 -0.058 inch)
Exhaust: 1.35 -1.65 mm (0.053 -0.065 inch)
CAUTION:
If the variation in the width exceeds 0.2 mm (0.01 inch) even if the contact width is within the standard value, replace or correct the valve seat.
REPAIR PROCEDURE OF VALVE SEAT
1. Check clearance between valve guide and valve and replace the valve guide if necessary before repairing the valve seat.
2. Repair the valve seat so that seat width and seat angle are to the specified shape.
3. Lap valve and valve seat with lapping compound after repairing valve seat.
REPLACEMENT PROCEDURE OF VALVE SEAT
1. Scrape the valve seat to be replaced from inside to make its wall thickness thin before pulling out.
2. Repair the valve seat hole of the cylinder head to match it with the diameter of the oversize valve seat to be press fitted.
Intake valve seat bore diameter:
0.3 0.S.: 36.22 -36.24 mm (1.426 -1.427 inches)
Exhaust valve seat bore diameter:
0.3 0.S.: 30.22 -30.24 mm (1.190 -1.191 inches)
3. Press fit the valve seat, taking care not to score the cylinder head bore at room temperature.
4. Ream the valve seat. Refer to "Repair procedure of valve seat."
REPLACEMENT PROCEDURE OF VALVE GUIDE
1. Pull out the valve guide with a press toward the cylinder block side.
2. Ream the valve guide hole of the cylinder head to match it with the diameter of the oversize valve guide to be press fitted.
CAUTION:
Do not use a valve guide with the same size as that of the pulled out valve guide because it cannot be press fitted.
Valve guide bore diameter
0.25 0.S.: 11.23 -11.25 mm (0.442 -0.443 inch)
3. Press fit the valve guide to the illustrated dimension. Standard value: 14.6 -15.2 mm (0.57 -0.60 inch)
NOTE: Press fit the valve guide from the cylinder head top surface.
4. After pressing fit the valve guide, insert a new valve to check for sliding.