Cylinder Head Assembly: Service and Repair
Removal
CAUTION:
^ When installing camshaft and oil seal, lubricate contacting surfaces with new engine oil.
^ When tightening cylinder head bolts, camshaft sprocket bolts and camshaft bracket bolts, lubricate bolt threads and seat surfaces with new engine oil.
^ Attach tags to valve lifters so as not to mix them up.
2. Release the fuel pressure.
1. Drain engine coolant. Be careful not to spill coolant on drive belts.
2. Release the fuel pressure. Refer to Powertrain Management; Fuel Delivery and Air Induction.
3. Remove the air duct to intake manifold collector.
4. Remove the engine drive belts.
5. Remove the front splash undercovers.
6. Remove the front exhaust tube.
7. Before removing the intake manifold collector from the engine, the following parts should be disconnected to remove the intake manifold collector:
^ EGR tube
^ Fuel injector connectors
^ Ground harness
^ Breather pipe
Harness connectors for:
^ IACV-AAC valve
^ Throttle position sensor
^ Throttle position switch
^ EGR temperature sensor
^ Water hoses from collector
^ Heater hoses
^ PCV hose
Vacuum hoses for:
^ EVAP canister
^ Power brake booster
^ Fuel pressure regulator
8. Remove the intake manifold rear supports.
9. Remove the exhaust manifold.
10. Remove the ignition coils.
11. Remove the spark plugs.
12. Remove the rocker cover bolts in numerical order as shown.
13. Set No. 1 piston at TDC on its compression stroke.
^ Rotate crankshaft until mating mark on camshaft sprocket is set at position indicated in figure.
14. Remove camshaft position sensor (PHASE).
^ Do not allow any magnetic materials to contact the camshaft position sensor (PHASE).
^ Be careful not to damage sensor.
15. Remove intake valve timing control solenoid.
16. Remove cylinder head front cover.
17. Remove timing chain guide from camshaft bracket.
18. Attach a suitable stopper pin to chain tensioner.
19. Remove chain tensioner.
20. Remove camshaft sprocket bolts.
^ Apply paint to timing chain and cam sprockets for alignment during installation.
21. Remove camshaft sprockets.
22. Remove camshaft brackets and camshafts.
^ Apply I.D. marks to brackets to ensure correct reassembly.
^ Bolts should be loosened in two or three steps.
23. Remove cylinder head bolts.
24. Remove cylinder head with intake manifold.
^ Head warping or cracking could result from removing in incorrect order.
^ Cylinder head bolts should be loosened in two or three steps.
Disassembly
1. Remove valve components with Tool.
2. Remove valve oil seal with a suitable tool.
Inspection
CYLINDER HEAD DISTORTION
^ Clean surface of cylinder head.
^ Use a reliable straightedge and feeler gauge to check the flatness of cylinder head mating surface.
^ Check along six positions shown in figure.
Head surface flatness
Standard: Less than 0.03 mm (0.0012 inch)
Limit: 0.1 mm (0.004 inch)
If beyond the specified limit, replace or resurface it.
Resurfacing limit:
The limit for cylinder head resurfacing is determined by the amount of cylinder block resurfacing.
Amount of cylinder head resurfacing is "A".
Amount of cylinder block resurfacing is "B".
The maximum limit is as follows: A + B = 0.2 mm (0.008 inch)
After resurfacing cylinder head, check that camshaft rotates freely by hand. If resistance is felt, replace cylinder head.
Nominal cylinder head height: 117.8 - 118.0 mm (4.638 - 4.646 inch)
CAMSHAFT VISUAL CHECK
Check camshaft for scratches, seizure and wear.
CAMSHAFT RUNOUT
1. Measure camshaft runout at the center journal.
Runout (Total indicator reading)
Standard: Less than 0.02 mm (0.0008 inch)
Limit: 0.1 mm (0.004 inch)
2. If it exceeds the limit, replace camshaft.
CAMSHAFT CAM HEIGHT
1. Measure camshaft cam height.
Standard cam height
Intake: 40.565 - 40.755 mm (1.5970 - 1.6045 inch)
Exhaust: 40.056 - 40.246 mm (1.5770 - 1.5845 inch)
Cam wear limit: 0.20 mm (0.0079 inch)
2. If wear is beyond the limit, replace camshaft.
CAMSHAFT JOURNAL CLEARANCE
1. Install camshaft bracket and tighten bolts to the specified torque.
2. Measure inner diameter of camshaft bearing.
Standard inner diameter
No. 1 bearing: 28.000 - 28.021 mm (1.1024 - 1.1032 inch)
No. 2 to No. 5 bearings
Intake: 23.985 - 24.006 mm (0.9443 - 0.9451 inch)
Exhaust: 24.000 - 24.021 mm (0.9449 - 0.9457 inch)
3. Measure outer diameter of camshaft journal.
Standard outer diameter
No. 1 journal: 27.935 - 27.955 mm (1.0998 - 1.1006 inch)
No. 2 to No. 5 journals: 23.935 - 23.955 mm (0.9423 - 0.9431 inch)
4. If clearance exceeds the limit, replace camshaft and/or cylinder head.
Camshaft journal clearance
Standard
Intake: 0.030 - 0.071 mm (0.0012 - 0.0028 inch)
Exhaust: 0.045 - 0.086 mm (0.0018 - 0.0034 inch)
Limit
Intake: 0.135 mm (0.0053 inch)
Exhaust: 0.150 mm (0.0059 inch)
CAMSHAFT END PLAY
1. Install camshaft in cylinder head.
2. Measure camshaft end play.
Camshaft end play
Standard: 0.115 - 0.188 mm (0.0045 - 0.0074 inch)
Limit: 0.20 mm (0.0079 inch)
3. If limit is exceeded, replace camshaft and remeasure end play.
^ If limit is still exceeded after replacing camshaft, replace cylinder head.
CAMSHAFT SPROCKET RUNOUT
1. Install sprocket on camshaft.
2. Measure camshaft sprocket runout.
Runout (Total indicator reading): Limit 0.15 mm (0.0059 inch)
3. If it exceeds the limit, replace camshaft sprocket.
VALVE GUIDE CLEARANCE
1. Measure valve deflection as shown in figure. (Valve and valve guide wear the most in this direction.)
Valve deflection limit (Dial gauge reading)
Intake & Exhaust: 0.2 mm (0.008 inch)
2. If it exceeds the limit, check valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diameter.
b. Calculate valve to valve guide clearance.
Valve stem to valve guide clearance = valve guide inner diameter - valve stem diameter.
c. Check that clearance is within specification.
^ If it exceeds the limit, replace valve and remeasure clearance.
^ If limit is still exceeded after replacing valve, replace valve guide.
VALVE GUIDE REPLACEMENT
1. To remove valve guide, heat cylinder head to 110° to 130°C (230° to 266°F).
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 suitable tool.
3. Ream cylinder head valve guide hole.
Valve guide hole diameter (for service parts)
Intake & Exhaust: 9.685 - 9.696 mm (0.3813 - 0.3817 inch)
4. Heat cylinder head to 110° to 130°C (230° to 266°F) and press service valve guide into cylinder head.
Projection "L": 11.5 - 11.7 mm (0.453 - 0.461 inch)
5. Ream valve guide.
Finished size
Intake & Exhaust: 5.500 - 5.515 mm (0.2165 - 0.2171 inch)
VALVE SEATS
Check valve seats for pitting at contact surface. Resurface or replace if excessively worn.
^ Before repairing valve seats, check valve and valve guide for wear. If they have worn, replace them. Then correct valve seat.
^ Use both hands to cut uniformly.
REPLACING VALVE SEAT FOR SERVICE PARTS
1. Bore out old seat until it collapses. Set machine depth stop so that boring cannot contact the bottom face of seat recess in cylinder head.
2. Ream cylinder head recess. The reaming bore for the service valve seat are:
Oversize: 0.5 mm (0.020 inch)
Intake: 31.500 - 31.516 mm (1.2402 - 1.2408 inch)
Exhaust: 26.500 - 26.516 mm (1.0433 - 1.0439 inch)
Use the valve guide center for reaming to ensure valve seat will have the correct fit.
3. Heat cylinder head to 110° to 130°C (230° to 266°F).
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 Engine; Specifications; Mechanical.
6. After cutting, lap valve seat with abrasive compound.
7. Check valve seating condition.
Seat face angle "a": 44°53' - 45°07'
Contacting width "W"
Intake: 1.06 - 1.34 mm (0.0417 - 0.0528 inch)
Exhaust: 1.34 - 1.63 mm (0.0528 - 0.0642 inch)
8. Use a depth gauge to measure the distance "L" 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 above to correct it. If the distance is longer, replace the valve seat.
Valve seat resurface limit
Intake: 35.95 - 36.55 mm (1.4154 - 1.4390 inch)
Exhaust: 35.92 - 36.52 mm (1.4142 - 1.4378 inch)
VALVE DIMENSIONS
Check dimensions of each valve. Refer to Engine; Specifications; Mechanical.
Valve head wear limit: 0.5 mm (0.020 inch)
Valve stem tip grinding allowance: 0.2 mm (0.008 inch)
VALVE SPRING
Squareness
1. Measure dimension "S".
Out-of-square "S": Less than 1.75 mm (0.0689 inch)
2. If it exceeds the limit, replace the spring.
Pressure
Check valve spring pressure at specified spring height.
Pressure
Standard: 370.0 N (37.73 kg, 83.19 lbs.) at 23.64 mm (0.9307 inch)
Limit: More than 347.8 N (35.46 kg, 78.19 lbs.) at 23.64 mm (0.9307 inch)
If not within specification, replace the spring.
VALVE LIFTER AND VALVE SHIM
1. Check contact and sliding surfaces for wear or scratches.
2. Check diameter of valve lifter and valve lifter guide bore.
Valve lifter outside diameter: 29.960 - 29.975 mm (1.1795 - 1.1801 inch)
Lifter guide inside diameter: 30.000 - 30.021 mm (1.1811 - 1.1819 inch)
Clearance between valve lifter and valve lifter guide: 0.025 - 0.065 mm (0.0010 - 0.0026 inch)
If it exceeds the limit, replace valve lifter or cylinder head which exceeds the standard diameter tolerance.
Assembly
1. Install valve component parts.
^ Always use new valve oil seal.
^ Before installing valve oil seal, install valve spring seat.
^ After installing valve components, tap valve stem tip with a plastic hammer to assure a proper fit.
^ Install valve spring (narrow pitch at both ends of spring) with either end toward cylinder head.
Installation
1. Before installing cylinder head gasket, apply a bead of Genuine RTV Silicone Sealant or equivalent, to mating surface of cylinder block as shown.
2. Install the cylinder head gasket.
^ When installing the cylinder head with manifolds, use a new cylinder head gasket.
Steps a - e
Sequence
Torque graph
3. Install cylinder head with intake manifolds, tighten the bolts in 5 steps (a - e).
^ Be sure to install washers between bolts and cylinder head.
^ Do not rotate crankshaft and camshaft separately, or valves will strike piston heads.
^ Apply new engine oil to cylinder head bolt threads and seat surfaces.
4. Install the camshafts as shown.
^ Make sure camshafts are aligned as shown.
5. Install camshaft brackets.
^ Make sure camshaft brackets are aligned as marked during disassembly.
^ Apply new engine oil to bolt threads and seat surface.
^ Tighten the camshaft bracket bolts in three stages.
Stage 1 - bolts 9 - 12, then bolts 1 - 8: 2.0 Nm (0.204 kg-m, 17.7 inch lbs.)
Stage 2 - bolts 1 - 12: 5.9 Nm (0.60 kg-m, 52.2 inch lbs.)
Stage 3 - bolts 1 - 12: 9.0 - 11.8 Nm (0.91 - 11.8 kg-m, 79 - 104 inch lbs.)
^ If any part of valve assembly or camshaft is replaced, check valve clearance according to reference data. After completing assembly check valve clearance. Refer to Engine; Specifications; Mechanical.
Reference - valve clearance (cold)
Intake: 0.25 - 0.33 mm (0.010 - 0.013 inch)
Exhaust: 0.32 - 0.40 mm (0.013 - 0.016 inch)
6. Install the camshaft sprockets.
^ Set timing chain by aligning mating marks with those of camshaft sprockets.
7. Install camshaft sprocket bolts to correct torque.
^ Apply new engine oil to bolt threads and seat surface.
8. Install the chain tensioner.
^ Before installing the chain tensioner, insert a suitable pin into pin hole of the chain tensioner.
^ After installing chain tensioner, remove the pin.
9. Install timing chain guide.
10. Install cylinder head front cover.
^ Apply RTV silicone sealant to cylinder head front cover.
^ Use Genuine RTV Silicone Sealant or equivalent.
11. Install camshaft position sensor (PHASE).
12. Install intake valve timing control solenoid.
13. Before installing rocker cover, apply a bead of Genuine RTV Silicone Sealant or equivalent to mating surface of cylinder head as shown.
14. Install rocker cover with rocker cover gasket and tighten bolts in numerical order as shown in the figure.
15. Install spark plugs.
16. Install ignition coils.
17. Install exhaust manifold.
18. Install intake manifold rear supports.
19. Connect the following components.
^ EGR tube
^ Ignition coils
^ Fuel injector connectors
^ Ground harness
^ Breather pipe
Harness connectors for:
^ IACV-AAC valve
^ Throttle position sensor
^ Throttle position switch
^ EGR temperature sensor
^ Water hoses from collector
^ Heater hoses
^ PCV hose
Vacuum hoses for:
^ EVAP canister
^ Power brake booster
^ Fuel pressure regulator
20. Install front exhaust tube.
21. Install front engine side covers.
22. Install air duct to intake manifold collector.
23. Install drive belts. Adjust drive belt deflection.
24. Install fuel pump fuse. Erase DTC if any DTC appears. Refer to Powertrain Management; Computers and Control Systems.