Cylinder Head Assembly: Service and Repair
REMOVAL
1. Release fuel pressure. Refer to Powertrain Management; Fuel Delivery and Air Induction.
2. Remove the strut tower brace.
3. Drain engine coolant and engine oil.
4. Remove the engine undercovers.
5. Remove the timing chain.
6. Remove the camshafts.
7. Remove the exhaust manifold.
8. Support the engine with suitable hoist and floor jack.
9. Remove cylinder head loosening bolts in the numerical order as shown.
10. If necessary to transfer to new cylinder head or remove for reconditioning, remove the intake manifold collector, intake manifold, and fuel tube assembly.
INSPECTION AFTER REMOVAL
Outer Diameter of Cylinder Head Bolts
^ Cylinder head bolts are tightened by using the plastic zone (Torque-to-yeild) tightening method. Whenever the size difference between d1 and d2 exceeds the limit, replace the bolts with new ones.
- Subtract the head bolt diameter measurement taken at d2 from the head bolt diameter measurement taken at d1. If the difference between d1 and d2 exceeds the limit, replace the bolts with new ones.
Limit (d1 - d2): 0.23 mm (0.0091 inch) or less
^ If reduction of outer diameter appears in a position other than d2, use it as d2 point.
INSTALLATION
1. Install a new cylinder head gasket.
2. Follow the steps below to tighten the cylinder head bolts in the numerical order as shown.
CAUTION:
^ If cylinder head bolts are re-used, check their outer diameters before installation. Refer to "Outer Diameter of Cylinder Head Bolts".
^ In step "c", loosen bolts in the order shown in the figure.
a. Apply new engine oil to the threads and the seating surfaces of mounting bolts.
b. Tighten all bolts to 98.1 Nm (10 kg-m, 72 ft. lbs.).
c. Completely loosen all bolts as shown in the figure.
d. Retighten all bolts to 34.3 - 44.1 Nm (3.5 - 4.4 kg-m, 26 - 32 ft. lbs.).
e. Turn all bolts 75° - 80° degrees (target: 75° degrees) clockwise.
f. Turn all bolts 75° to 80° degrees (target: 75° degrees) clockwise again.
CAUTION: Check and confirm the tightening angle by using angle wrench or protractor. Avoid judgment by visual inspection without the tool.
3. Installation of the remaining components is in reverse order of removal.
DISASSEMBLY
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 surfaces when installing the cylinder head, camshaft sprocket, crankshaft pulley and camshaft bracket.
^ Attach tags to valve lifters so all parts are assembled in their original position.
1. Remove the valve lifter.
^ Confirm installation point.
2. Remove the valve collet.
^ Compress valve spring with valve spring compressor. Remove valve collet with magnet driver.
3. Remove valve spring retainer and valve spring.
CAUTION: Do not remove valve spring seat from valve spring.
4. Push valve stem to combustion chamber side, and remove valve.
^ Inspect valve guide clearance before removal.
^ Confirm installation point.
5. Remove valve oil seal with valve oil seal puller.
6. When valve seat must be replaced, refer to "VALVE SEAT REPLACEMENT".
7. When valve guide must be replaced, refer to "VALVE GUIDE REPLACEMENT".
8. Remove spark plug with spark plug wrench.
ASSEMBLY
1. Install valve guide. Refer to "VALVE GUIDE REPLACEMENT"
2. Install valve seat. Refer to "VALVE SEAT REPLACEMENT".
3. Install valve oil seal.
^ Install with valve oil seal drift to match dimension in illustration.
4. Install valve.
^ Install larger diameter to intake side.
5. Install valve spring.
^ Install smaller pitch (valve spring seat side) to cylinder head side.
^ Confirm the identification color of the valve spring:
Intake: blue
Exhaust: yellow
6. Install valve spring retainer.
7. Install valve collet.
^ Compress valve spring with valve spring compressor. Install valve collet with magnet wand.
^ Tap stem edge lightly with plastic hammer after installation to check its installed condition.
8. Install valve lifter.
9. Install spark plug.
Inspection After Disassembly
CYLINDER HEAD DISTORTION
1. Wipe off oil and remove water scale deposits, old gasket, old sealer, and carbon with a scraper.
CAUTION: Use care not to allow gasket debris to enter passages for oil or water.
2. At each of several locations on bottom surface of cylinder head, measure distortion in six directions.
Standard: 0.1 mm (0.004 inch) or less
VALVE DIMENSIONS
Check dimensions of each valve. Refer to Engine; Specifications; Mechanical.
VALVE GUIDE CLEARANCE
Perform this inspection before removing the valve guide.
1. Make sure that the valve stem diameter is within the specification.
2. Push the valve out by approximately 15 mm (0.59 inch) toward the combustion chamber side to measure the valve's run-out volume (in the direction of dial gauge) with dial gauge.
3. Half of the run-out volume accounts for the valve guide clearance.
Intake: 0.020 - 0.053 mm (0.0008 - 0.0021 inch) or run-out less
Exhaust: 0.030 - 0.063 mm (0.0012 - 0.0025 inch) or run-out less
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 (2.2 ton-force) pressure] or hammer and suitable tool.
3. Ream cylinder head valve guide hole.
Valve guide hole diameter for 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. Press valve guide from camshaft side to dimensions as in illustration.
6. Using valve guide reamer, apply reamer finish to valve guide.
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 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 seat 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 the valve seat.
VALVE SEAT REPLACEMENT
When valve seat is removed, replace with an 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 the cylinder head. Set the machine depth stop to ensure this.
2. Ream cylinder head recess diameter for service valve seat.
Oversize: 0.5 mm (0.020 inch)
Intake: 37.000 - 37.016 mm (1.4567 - 1.4573 inch)
Exhaust: 32.000 - 32.016 mm (1.2598 - 1.2605 inch)
^ Be sure to ream in circles concentric to the valve guide center. This will enable the valve seat 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 the cold valve seats.
5. Using a valve seat cutter set or a valve seat grinder, finish the seat to the specified dimensions.
CAUTION: When using valve seat cutter, firmly grip the cutter handle with both hands. Then, press on the contacting surface all around the circumference to cut in a single drive. Improper pressure on the cutter or cutting many different times may result in a defective valve seat.
Grind to obtain the dimensions indicated as shown.
Standard
D1 dia.: 33.5 mm (1.3189 inch)
D2 dia.: 35.1 - 35.3 mm (1.382 - 1.390 inch)
D3 dia.: 39.0 - 39.2 mm (1.535 - 1.543 inch)
D4 dia.: 28 mm (1.10 inch)
D5 dia.: 29.9 - 30.1 mm (1.177 - 1.185 inch)
D6 dia.: 33.5 - 33.7 mm (1.319 - 1.327 inch)
6. Using compound, grind to adjust valve fitting.
7. Check again for normal contact.
VALVE SPRING SQUARENESS
Set try square along the side of the valve spring and rotate the spring. Measure the maximum clearance between the top face of the spring and the try square.
Limit: 1.9 mm (0.0748 inch)
VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD
Check valve spring pressure with valve spring seat installed at specified spring height. Replace if not within specifications.
CAUTION: Do not remove the valve spring seat.
Specifications