Disassembly and Assembly
Disassembly and Assembly
CAUTION:
^ When installing camshafts, chain tensioners, oil seals, or other sliding parts, lubricate contacting surfaces with new engine oil.
^ Apply new engine oil to threads and seat surface when installing cylinder head, camshaft sprocket, crankshaft pulley, and camshaft bracket.
^ Attach tags to valve lifters so as not to mix them up.
DISASSEMBLY
1. Remove valve lifter.
^ Mark position for installation.
2. Remove valve collet.
^ Compress valve spring using Tool. Remove valve collet with magnet driver.
Tool numbers : KV10116200 (J26336-B) : KV10115900 (J26336-20) : KV10109230 ( - )
3. Remove valve spring retainer, valve spring, and valve spring seat.
4. Push valve stem to combustion chamber side, and remove valve, mark for assembly.
^ Inspect valve guide clearance before removal. Refer to "VALVE GUIDE CLEARANCE".
^ Confirm installation point.
5. Remove the valve oil seals using Tool.
Tool number : KV10107902 (J38959)
6. If valve seat must be replaced, refer to "VALVE SEAT REPLACEMENT".
7. If valve guide must be replaced, refer to "VALVE GUIDE REPLACEMENT".
8. Remove spark plug with spark plug wrench.
9. Remove spark plug tube, as necessary.
^ Using a pair of pliers, pull spark plug tube out of cylinder head.
CAUTION:
^ Be careful not to damage cylinder head.
^ Once removed, a spark plug tube will be deformed and cannot be reused. Do not remove it unless absolutely necessary.
Inspection After Disassembly
CYLINDER HEAD DISTORTION
^ Clean the surface of the cylinder head. Use a reliable straightedge and feeler gauge to check the flatness of cylinder head surface.
^ Check along six positions as shown.
Head surface distortion Limit : 0.1 mm (0.004 inch)
^ If beyond the specified limit, resurface or replace it.
^ The limit for cylinder head resurfacing is determined by the cylinder block resurfacing.
Resurfacing Limit
Amount of cylinder head resurfacing is "A".
Amount of cylinder block resurfacing is "B".
The maximum limit : A + B = 0.2 mm (0.008 inch)
^ After resurfacing cylinder head, check that camshaft rotates freely by hand. If resistance is felt, cylinder head must be replaced.
Nominal cylinder head height "H" : 126.3 - 126.5 mm (4.972 - 4.980 inch)
VALVE DIMENSIONS
Check dimensions of each valve, refer to "Valve Dimensions".
VALVE GUIDE CLEARANCE
1. Measure valve deflection as shown in the figure. (Valve and valve guide mostly wear in this direction.)
Valve deflection limit (dial gauge reading)
Intake : 0.24 mm (0.0094 inch)
Exhaust : 0.28 mm (0.0110 inch)
2. If it exceeds the limit, check valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diameter.
b. Check that clearance is within specification.
Valve to valve guide clearance standard
Intake : 0.020 - 0.053 mm (0.0008 - 0.0021 inch)
Exhaust : 0.030 - 0.063 mm (0.0012 - 0.0025 inch)
Valve to valve guide clearance limit
Intake : 0.08 mm (0.0031 inch)
Exhaust : 0.09 mm (0.004 inch)
c. If it exceeds the limit, replace valve or valve guide.
VALVE GUIDE REPLACEMENT
When valve guide is removed, replace with oversized [0.2 mm (0.008 inch)] valve guide.
1. To remove valve guide, heat cylinder head to 110° - 130°C (230° - 266°F) by soaking in heated oil.
2. Drive out the valve guide with a press [under a 20 kN (2.2 US ton) pressure] or hammer and suitable tool.
WARNING: Cylinder head is hot. Wear protective equipment to prevent getting burned.
3. Ream cylinder head valve guide hole.
Valve guide hole diameter(for service parts), intake and exhaust : 10.175 - 10.196 mm (0.4006 - 0.4014 inch)
4. Heat cylinder head to 110° - 130°C (230° - 266°F) by soaking in heated oil and press new valve guide from camshaft side into the cylinder head to the dimensions as shown.
Projection "L" : 12.6 - 12.8 mm (0.496 - 0.504 inch)
5. Using a valve guide reamer, apply a reamer finish to the valve guide.
Intake and exhaust finished size : 6.000 - 6.018 mm (0.2362 - 0.2369 inch)
VALVE SEAT CONTACT
^ After confirming that the dimensions of valve guides and valves are within specifications, perform this procedure.
^ Apply Prussian blue onto contacting surface of valve seat to check the condition of the valve contact on the surface.
^ Check if the contact area band is continuous all around the circumference.
^ If not, grind to adjust valve fitting and check again. If the contacting surface still has N.G conditions even after the re-check, replace valve seat.
VALVE SEAT REPLACEMENT
1. Bore out old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess in cylinder head. Set the machine depth stop to ensure this.
2. Ream cylinder head recess for service valve seat.
Oversize : 0.5 mm (0.020 inch)
Intake : 38.500 - 38.516 mm (1.5157 - 1.5164 inch)
Exhaust : 32.700 - 32.716 mm (1.2874 - 1.2880 inch)
^ Be sure to ream in circles concentric to the valve guide center.
^ This will enable valve seat to fit correctly.
3. Heat cylinder head to 110° - 130°C (230° - 266°F) by soaking in heated oil.
4. Press fit valve seat until it seats on the bottom.
5. Cut or grind valve seat using suitable tool to the specified dimensions. Refer to "VALVE".
6. After cutting, lap valve seat with abrasive compound.
7. Check valve seating condition.
Seat face angle "a" : 45° 25° - 45° 75° degrees/minutes
Contacting width "W" for intake : 1.09 - 1.31 mm (0.0429 - 0.0516 inch)
Contacting width "W" for exhaust : 1.29 - 1.51 mm (0.0508 - 0.0594 inch)
8. Use a depth gauge to measure the distance between the mounting surface of the cylinder head spring seat and the valve stem end. If the distance is shorter than specified, repeat step 5 to adjust it. If it is longer, replace the valve seat with a new one.
Valve seat resurface limit "L" intake : 41.07 - 41.67 mm (1.6169 - 1.6405 inch)
Valve seat resurface limit "L" exhaust : 41.00 - 41.60 mm (1.6142 - 1.6378 inch)
VALVE SPRING SQUARENESS
Set try square along the side of valve spring and rotate the spring. Measure the maximum clearance between the top face of spring and try square.
Out-of-square limit : Less than 2.0 mm (0.079 inch)
VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD
Check valve spring pressure at specified spring height.
Standard : 166 - 188 N (16.9 - 19.2 kg, 37.3 - 42.3 lbs.) at height 37.0 mm (1.457 inch)
Limit : 378 - 426 N (38.6 - 43.5 kg, 85.0 - 95.8 lbs.) at height 27.8 mm (1.094 inch)
If it is not within specifications, replace the spring.
ASSEMBLY
1. Install valve guide. Refer to "VALVE GUIDE REPLACEMENT".
2. Install valve seat. Refer to "VALVE SEAT REPLACEMENT".
3. Install new valve spring seats and new valve oil seals using
Tool. Tool number : (J39386)
^ Install with valve oil seal drift to match dimension in illustration.
NOTE: Dimension "H": Height measured before valve spring seat installation.
Height "H"
Intake and exhaust : 14.3 - 14.9 mm (0.563 - 0.587 inch)
4. Install the valves in their original position, as marked during disassembly.
5. Install valve spring (uneven pitch type).
^ Install smaller pitch end (paint mark) to cylinder head side (valve spring seat side).
6. Install valve spring retainer.
7. Install valve collet.
Tool numbers : KV10116200 (J26336-B) : KV10115900 (J26336-20) : KV10109230 ( - )
^ Compress valve spring using Tool and install valve collet.
^ Tap stem edge lightly with plastic hammer after installation to check its installed condition.
8. Install valve lifter.
9. Install spark plug tube as follows:
a. Remove old liquid gasket from cylinder head mounting hole.
b. Apply liquid gasket to area within approximately 12 mm (0.47 inch) from edge of spark plug tube press fit side.
^ Use Genuine RTV Silicone Sealant or equivalent. Refer to "RECOMMENDED CHEMICAL PRODUCTS AND SEALANTS".
c. Using a drift, press fit the spark plug tube so that it height "H" is as specified.
Standard press fit height "H" :38.55 - 38.65 mm (1.5177 - 1.5217 inch)
CAUTION:
^ When press fitting, take care not to deform spark plug tube.
^ After press fitting, wipe off liquid gasket protruding onto cylinder head upper face.
10. Install spark plug with spark plug wrench.
Spark plug : 20 - 29 Nm (2.0 - 3.0 kg-m, 14 - 22 ft. lbs.)