Cylinder Head
Cylinder Head
Cylinder Head and Associated Parts
Disassembly
Note:
^ During disassembly, be sure that the valve train components are kept together and identified so that they can be reinstalled in their original locations.
^ Before removing the cylinder head from the engine and before disassembling the valve mechanism, perform a compression test and note the results.
1. Remove camshaft drive gear pulley fixing bolt (3), then pulley (4).
2. Remove camshaft bearing cap fixing bolt (5), camshaft bracket (6), then camshaft exhaust (7), and intake side (8).
3. Remove tappet with shim (11).
4. Use the J-8062 valve spring compressor and J-42898 valve spring compressor adapter to remove the split collar (12), valve spring with upper seat (13) and valve (14).
5. Remove spark plug (1).
Caution: Do not remove the spark plugs when the head and plugs are hot. Clean dirt and debris from spark plug recess areas before removal.
Clean
Cylinder head
Carefully remove all varnish, soot and carbon from the bare metal. Do not use a motorized wire brush on any gasket sealing surface.
Inspection and Repair
1. Cylinder head gasket and mating surfaces for leaks, corrosion and blow-by. If the gasket has failed, determine the cause.
- Insufficient torque on head bolts.
- Improper installation
- Loose or warped cylinder head
- Missing dowel pins
- Warped case surface
2. Cylinder head for cracks, especially between valve seats and in the exhaust ports.
3. Cylinder head deck for corrosion, sand particles in head and porosity.
Caution:
^ Do not attempt to weld the cylinder head. Replace it.
^ Do not reuse cylinder head bolts.
4. Cylinder head deck, common chamber and exhaust manifold mating surfaces for flatness. These surfaces may be reconditioned by milling. If the surfaces are "out of flat" by more than specification, the surface should be ground to within specifications. Replace the head if it requires machining beyond the repairable limit.
Head surface and manifold surface
Standard: 0.05 mm (0.002 inch) or less
Warpage limit: 0.2 mm (0.0079 inch)
Maximum Repairable limit: 0.2 mm (0.0079 inch)
Head height
Standard height: 133.2 mm (5.2441 inch)
Warpage limit: 0.2 mm (0.0079 inch)
Maximum Repairable limit: 133.0 mm (5.2362 inch)
5. Water jacket sealing plugs seating surfaces.
Reassembly
1. Install Spark plug and tighten all the spark plugs to specified torque.
Torque: 18 Nm (13 ft. lbs.)
2. Tighten sub gear setting bolt.
1. Use J-(42686 gear spring lever) to turn sub gear to right direction until the M5 bolt aligns with the hole between camshaft driven gear and sub gear.
2. Tighten the M5 bolt to a suitable torque to prevent the sub gear from moving.
3. Install camshaft drive gear assembly and tighten three bolts to the specified torque.
Torque: 10 Nm (87 ft. lbs.)
4. Install camshaft assembly and camshaft brackets, tighten twenty bolts on one side bank to the specified torque.
1. Apply engine oil to camshaft journal and bearing surface of camshaft bracket.
2. Align timing mark on intake camshaft (one dot for right bank, two dots for left bank) and exhaust camshaft (one dot for right bank, two dots for left bank) to timing mark on camshaft drive gear (one dot).
3. Tighten twenty bolts in numerical order on one side bank as shown in the illustration.
Torque: 10 Nm (89 inch lbs.)
5. Tighten bolt for camshaft drive gear assembly pulley to the specified torque.
Torque: 98 Nm (72 ft. lbs.)