| TIBURON(GK) >2004 > G 2.7 DOHC > Engine Mechanical System > Cylinder Head Assembly > Valve>Repair procedures |

DISASSEMBLY
1. | Drain the coolant and disconnect the upper radiator hose.
2. | Remove the breather hose and air-intake hose.
3. | Remove the vacuum hose, fuel hose and coolant hose.
4. | Remove the intake manifold.
5. | Remove the cables from the spark plugs. The cables should be removed by holding the boot portion.
6. | Remove the ignition coil.
7. | Remove the upper and lower timing belt cover.
8. | Remove the timing belt and camshaft sprockets.
9. | Remove the heat protector and exhaust manifold assembly.
10. | Remove the coolant pump pulley and head cover.
11. | Remove the intake and exhaust camshaft.
12. | Remove the cylinder head assembly. The cylinder head bolts should be removed using the S12 mm socket, in two or three steps.
13. | Clean the gasket pieces from the cylinder block top surface and cylinder head bottom surface.
Make sure that fragments from the gasket do not fall in the engine.
INSPECTION
1. | Remove scale, sealing compound and carbon deposits. After cleaning oil passages, apply compressed air to make certain that the passages are notclogged.
2. | Visually check the cylinder head for cracks, damage or water leakage.
3. | Check the cylinder head surface for flatness with a straight edge and feeler gauge as shown in the illustration.
Cylinder head flatness Standard dimensions : Max. 0.03mm (0.0059 in.) Service limit : 0.05mm (0.0020 in.)
Valve Guides
Valve stem-to-guide clearance Standard value Intake : 0.02 ~ 0.05mm (0.0009 ~ 0.0020in.) Exhaust : 0.035 ~ 0.065mm (0.0014 ~ 0.0026 in.) Service limit Intake : 0.10mm(0.0039 in.) Exhaust : 0.15mm(0.0059 in.)
Valve
1. | Replace the valve if its stem is bent, worn or damaged. Also replace it if the stem end (the surface contacting the hydraulic-lash adjuster) ishollowed out.
2. | Check the valve face contact area, and recondition or replace as necessary.
3. | Replace the valve if the width of the margin (thickness of the valve head) is less than the minimum specified.
Valve margin Standard value Intake : 1.0mm(0.0394 in.) Exhaust : 1.3mm(0.0512 in.) Service limit Intake : 0.5mm (0.0197in.) Exhaust : 0.8mm (0.0315in.)
Valve Spring
1. | Check the free height of each valve spring and replace if necessary.
2. | Using a square, test the squareness of each valve spring. If the spring is excessively out-of-square, replace it.
Valve spring Standard value Free height : 42.5mm (1.6732 in.) Load : 21.9kg/35mm (48.4 lb/1.3780in.) Out of squareness : Max. 1.5° Service limit Load : 21.9kg/34mm (48.4 lb/1.3386in.) Out of squareness : Max. 3°
Replacing Valve Guide
1. | Using the special tool (09221-3F100 A/B), withdraw the old valve guide out the bottom of the cylinder head.
2. | Recondition the valve guide hole so that it can receive the newly press-fitted oversize valve guide. Valve Guide Oversizes
Size mm (in.) | Size mark | Oversize valve guide hole size mm(in.)
0.05 (0.002) O.S. | 5 | 11.050 ~ 11.068 (0.435 ~ 0.4357)
0.25 (0.010) O.S. | 25 | 11.250 ~ 11.268 (0.443 ~ 0.4436)
0.50 (0.020) O.S. | 50 | 11.500 ~ 11.518 (0.453 ~ 0.4535)
3. | Using the special tool (09221-3F100 A/B) press-fit the valve guide. The valve guide must be press-fitted from the upper side of the cylinder head. Keep in mind that the intake and exhaust valve guidesare different in length.
4. | After the valve guide is press-fitted, insert a new valve and check for proper clearance.
5. | After the valve guide is replaced, check that the valve is fully seated. Recondition the valve seats as necessary.
Do not install a valve guide unless it is oversize.
Replacing Valve Seat Ring
1. | Cut away the inner face of the valve seat to reduce the wall thickness.
2. | Enlarge the diameter of the valve seat so that it matches the specified hole diameter of the new valve seat ring. Valve Seat Ring Oversizes
Description | Size mm (in.) | Size mark | Seat ring height H mm (in.) | Oversize hole diameter I.D. mm(in.)
Intake valve Seat ring | 0.3 (0.012) O.S. | 30 | 7.9 ~ 8.1 (0.311 ~ 0.319) | 33.300 ~ 33.325 (1.311 ~ 1.312)
Exhaust valve Seat ring | 0.3 (0.012) O.S. | 30 | 7.9 ~ 8.1 (0.311 ~ 0.319) | 28.600 ~ 28.625 (1.126 ~ 1.127)
3. | Heat the cylinder head to about 250°C (480°F) and press-fit an oversize seat ring for the bore in the cylinder head.
4. | Using lapping compound, lap the valve to the new seat.
Valve seat contact width Intake : 1.1 ~ 1.5mm (0.043 ~ 0.059in.) Exhaust : 1.3 ~ 1.7mm(0.051 ~ 0.067 in.)
REASSEMBLY
1. | Install the spring seats.
2. | Using special tool (09222-22001), lightly tap the seal in position.
• | Do not reuse old valve stem seals.
• | Incorrect installation of the seal could result in oil leakage of from the valve guides.
3. | Apply engine oil to each valve. Insert the valve into their guides. Avoid pushing the valve into the seal by force. After installing the valve,check that it moves smoothly.
4. | Place valve springs so that the side coated with enamel faces toward the valve spring retainer.
5. | Using the special tool (09222-28000, 09222-28100), compress the spring and install the retainer locks. After installing the valves, ensure that the retainer locks are correctly in place before releasing the valvespring compressor.
When the spring is compressed, check that the valve stem seal is not pressed against the bottom of the retainer.
6. | Clean both gasket surfaces of the cylinder head and cylinder block.
7. | Verify the identification marks on the cylinder head gasket.
8. | Install the gasket so that the surface with the identification mark faces toward the cylinder head.
Do not apply sealant to these surfaces.
9. | Tighten the cylinder head bolts in the sequence shown in the illustration with a torque wrench.
10. | Tighten the cylinder head bolts using the torque-angle method. Starting at top center, tighten all cylinder head bolts in sequence as shown in the illustration, using the 12 mm socket.
Tightening procedure Cylinder head bolt : 25Nm (250kg.cm, 18.1lb.ft) + (58°~62°) + (43°~47°)