Disassembly and Assembly
Disassembly and Assembly
COMPONENTS
DISASSEMBLY
1. Remove spark plug with spark plug wrench (commercial service tool).
2. Remove adjusting shim and valve lifter.
^ Identify installation positions, and store them without mixing them up.
3. Remove valve collet.
^ Compress valve spring with valve spring compressor, attachment and adapter (SST). Remove valve collet with magnetic hand.
CAUTION: When working, take care not to damage valve lifter holes.
4. Remove valve spring retainer and valve spring (with valve spring seat).
CAUTION: Do not remove valve spring seat from valve spring.
5. Push valve stem to combustion chamber side, and remove valve.
^ Identify installation Positions. and store them without mixing them Up.
6. Remove valve oil seal with valve oil seal puller (SST).
7. If valve seat must be replaced.
8. If valve guide must be replaced.
9. Remove spark plug tube, as necessary.
^ Using pair of pliers, pull spark plug tube out of cylinder head.
CAUTION:
^ Take care not to damage cylinder head.
^ Once removed, spark plug tube will be deformed and cannot be reused. Do not remove it unless absolutely necessary.
ASSEMBLY
1. When valve guide is removed, install it.
2. When valve seat is removed, install it.
3. Install new valve oil seal as follows:
a. Apply new engine oil on valve oil seal joint and seal lip.
b. Install with valve oil seal drift (SST) to match dimension in the figure.
4. Install valve.
^ Install in the original position.
NOTE: Larger diameter valves are for intake side.
5. Install valve spring (with valve spring seat).
^ Install smaller pitch (valve spring seat side) to cylinder head side.
6. Install valve spring retainer.
7. Install valve collet.
^ Compress valve spring with valve spring compressor, attachment and adapter (SST). Install valve collet with magnetic hand.
CAUTION: When working, take care not to damage valve lifter holes.
^ Tap stem edge lightly with plastic hammer after installation to check its installed condition.
8. Install valve lifter and adjusting shim.
^ Install in the original position.
9. Install spark plug tube as follows:
^ Press-fit spark plug tube following procedure below.
a. Remove old liquid gasket adhering to cylinder-head mounting hole.
b. Apply sealant to area within approximately 12 mm (0.47 inch)from edge of spark plug tube press-fit side.
Use Genuine High Strength Locking Sealant or equivalent .
c. Using drift, press-fit spark plug tube so that its height "H" is as specified in the figure. Standard press-fit height "H":
: 38.4 - 39.4 mm (1.512 -1.551 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 (commercial service tool).
Inspection After Disassembly
VALVE DIMENSIONS
^ Check the dimensions of each valve.
^ If the dimensions are out of the standard, replace valve and check the valve seat contact.
VALVE GUIDE CLEARANCE
Valve Stem Diameter
Measure the diameter of valve stem with micrometer.
Standard
Intake : 5.972 - 5.980 mm (0.2351 - 0.2354 inch)
Exhaust : 5.962 - 5.970 mm (0.2347 - 0.2350 inch)
Valve Guide Inner Diameter
Measure the inner diameter of valve guide with inside micrometer.
Standard
Intake and Exhaust : 6.000 - 6.018 mm (0.2362 - 0.2369 inch)
Valve Guide Clearance
(Valve guide clearance) = (Valve guide inner diameter) - (Valve stem diameter).
Valve guide clearance:
Standard
Intake : 0.020 - 0.046 mm (0.0008 - 0.0018 inch)
Exhaust : 0.030 - 0.056 mm (0.0012 - 0.0022 inch)
Limit
Intake : 0.08 mm (0.003 inch)
Exhaust : 0.1 mm (0.004 in)
^ If the calculated value exceeds the limit, replace valve and/or valve guide. When valve guide must be replaced.
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 to 130°C (230 to 266°F) by soaking in heated oil.
2. Drive out valve guide with a press [under a 20 kN (2 ton, 2.2 US ton, 2.0 Imp ton) pressure] or hammer and valve guide drift (commercial service tool).
CAUTION: Cylinder head contains heat. When working, wear protective equipment to avoid getting burned.
3. Using valve guide reamer (commercial service tool), 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 to 130°C (230 to 266°F) by soaking in heated oil.
5. Using valve guide drift (commercial service tool), press valve guide from camshaft side to the dimensions as in the figure.
CAUTION: Cylinder head contains heat. When working, wear protective equipment to avoid getting burned.
6. Using valve guide reamer (commercial service tool), apply reamer finish to valve guide.
Standard:
Intake and exhaust: 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 the specifications, perform this procedure.
^ Apply prussian blue (or white lead) 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 "NG" conditions even after the re-check, replace valve seat.
VALVE SEAT REPLACEMENT
When valve seat is removed, replace with oversized [0.5 mm (0.020 inch)] valve seat.
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.
CAUTION: Prevent to scratch cylinder head by excessive boring.
2. Ream cylinder head recess diameter for service valve seat.
Oversize [0.5 mm (0.020 inch)]
Intake : 37.500 - 37.516 mm (1.4764 - 1.4770 inch)
Exhaust : 32.700 - 32.716 mm (1.2874 - 1.2880 inch)
^ Be sure to ream in circles concentric to valve guide center. This will enable valve to fit correctly.
3. Heat cylinder head to 110 to 130°C (230 to 266°F) by soaking in heated oil.
4. Provide valve seats cooled well with dry ice. Force fit valve seat into cylinder head.
CAUTION: . Avoid directly touching cold valve seats.
^ Cylinder head contains heat. When working. wear protective equipment to avoid netting burned.
5. Using valve seat cutter set (commercial service tool) or valve seat grinder, finish seat to the specified dimensions.
CAUTION: When using valve seat cutter, firmly grip cutter handle with both hands. Then, press on the contacting surface all around the circumference to cut in a single drive. Improper pressure on with cutter or cutting many different times may result in stage valve seat.
6. Using compound, grind to adjust valve fitting.
7. Check again for normal contact.