Cylinder Head and Valves
CYLINDER HEAD AND VALVESREMOVAL AND INSTALLATION
Removal Steps 1-21:
REMOVAL SERVICE POINTS
A CYLINDER HEAD BOLT REMOVAL
1. Using the special tool, loosen the cylinder head bolts. Loosen evenly, little by little.
RETAINER LOCK REMOVAL
1. Using the special tool, compress the spring.
2. Remove the retainer locks.
Keep removed parts in order according to the cylinder number and intake/exhaust.
VALVE STEM SEAL REMOVAL
1. Do not reuse the stem seals.
INSPECTION
1. Only features differing from the single camshaft engine are described in the following.
CYLINDER HEAD
Cylinder head height (when new): 131.9-132.1 mm (5.193-5.201 in.)
VALVE
Margin:
Intake : 1.0 mm (.039 in.)
Exhaust : 1.5 mm (.059 in.)
Limit:
Intake : 0.7 mm (.028 in.)
Exhaust : 1.0 mm (.039 in.)
VALVE SPRING
Free height: 48.3 mm (1.90 in.)
Limit: 47.4 mm (1.866 in.)
Squareness: 1.5° or less
Limit: Max. 4°
VALVE GUIDE
Valve guide to valve stem clearance:
Intake : 0.02-0.05 mm (0.0008-0.0020 in.)
Exhaust : 0.05-0.09 mm (0.0020-0.0035 in.)
Limit:
Intake : 0.10 mm (0.004 in.)
Exhaust : 0.15 mm (0.006 in.)
VALVE SEAT RECONDITIONING PROCEDURE
1. Before correcting the valve seat, check for clearance between the valve guide and valve and, if necessary, replace the valve guide.
2. Using the special tool or seat grinder; correct to obtain the specified seat width and angle.
3. After correction, valve and valve seat should be lapped with a lapping compound.
VALVE SEAT REPLACEMENT PROCEDURE
1. Cut the valve seat to be replaced from the inside to thin the wall thickness. Then, remove the valve seat.
2. Rebore the valve seat hole in the cylinder head to a selected oversize valve seat diameter.
Rework Dimensions:
Seat ring hole diameter: See "Rework Dimensions".
3. Before fitting the valve seat, either heat the cylinder head up to approximately 250 °C (482 °F) or cool the valve seat in liquid nitrogen, to prevent the cylinder head bore from galling.
4. Using a valve seat cutter, correct the valve seat to the specified width and angle.
See "VALVE SEAT RECONDITIONING PROCEDURE".
Intake valve seat hole diameter
0.3 O.S 35.30-35.33 mm (1.3898-1.3909 in.)
0.6 O.S 35.60-35.63 mm (1.4016-1.4028 in.)
Exhaust valve seat hole diameter
0.3 O.S 33.30-33.33 mm (1.3110-1.3122 in.)
0.6 O.S 33.60-33.63 mm (1.3228-1.3240 in.)
VALVE GUIDE REPLACEMENT PROCEDURE
1. Using the special tool and a press, remove the valve guide toward cylinder head gasket surface.
2. Rebore valve guide hole to the new oversize valve guide outside diameter.
Rework Dimensions:
Valve guide hole diameter: See "Rework Dimensions".
NOTE: Do not install a valve guide of the same size again.
3. Using the special tool, press-fit the valve guide, working from the cylinder head top surface.
4. After installing valve guides, insert new valves in them to check for sliding condition.
5. When valve guides have been replaced, check for valve contact and correct valve seats as necessary.
Valve Guide Hole Diameter
0.05 O.S 12.05-12.07 mm (0.4744-0.4752 in.)
0.25 O.S 12.25-12.27 mm (0.4823-0.4831 in.)
0.50 O.S 12.50-12.52 mm (0.4921-0.4929 in.)
INSTALLATION SERVICE POINTS
A VALVE STEM SEAL INSTALLATION
1. Install the valve spring seat.
2. Using the special tool, install a new stem seal to the valve guide.
Caution: Do not reuse the valve stem seal.
B VALVE SPRING INSTALLATION
1. Install the valve spring so that its end with identification color is positioned on the rocker arm end.
C RETAINER LOCK INSTALLATION
1. Using the special tool, compress the valve spring and insert the retainer lock into position.
D CYLINDER HEAD GASKET IDENTIFICATION
Identification mark:
16 (4G61)
20 (4G63)
E CYLINDER HEAD BOLT INSTALLATION
1. Tighten the cylinder head bolts in the sequence shown. Each bolt should be tightened in two to three steps, torquing progressively Tighten to the specified torque in the final sequence.