Removal and Replacement
REMOVAL
1. Remove the cylinder head bolts as shown in the illustration.
2. Using 12 mm socket, remove the retainer lock. Next remove the spring retainer, valve spring, spring seat and valve.
NOTE: Keep these parts so that they can be reinstalled in their original positions.
3. Remove the valve stem seals with pliers, and discard.
NOTE: Do not reuse the valve stem seals.
INSPECTION
Cylinder head
1. Check the cylinder head for cracks damage and coolant leakage. If cracked, replace the cylinder head.
2. Remove scale, sealing compound and carbon deposits completely. After cleaning oil passages, apply compressed air to them to make certain that the passages are not clogged.
3. Check the cylinder head gasket surface for flatness by using a straight edge in the direction of A, B, ... as shown. If flatness exceeds service limit in any direction, either replace the cylinder head, or lightly machine the cylinder head gasket surface.
Flatness of cylinder head gasket surface
[Standard dimension] Less than 0.05 mm (0.002 inch)
[Limit] 0.2 mm (0.008 inch)
Valves
1. Using a wire brush, clean the valve thoroughly.
2. Check each valve for wear, damage and distortion of head and stem at B. Repair or correct if necessary.
If stem end A is pitted or worn, resurface as necessary. This correction must be limited to a minimum. Also resurface the valve face.
Replace the valve if the margin has decreased to less than the service limit.
Margin
[Standard dimension]
Intake 1.0 mm (0.040 inch)
Exhaust 1.5 mm (0.059 inch)
[Limit]
Intake 0.7 mm (0.028 inch)
Exhaust 1.0 mm (0.040 inch)
Valve Springs
1. Check free length and tension of the valve spring. If they exceed the service limit, replace the spring.
2. Using a square, test the squareness of each spring. If the spring is excessively out of square, replace it.
Valve spring
[Standard Value]
Free height 45.82 mm (1.804 inch)
Load 248 N (55 lbs.) at installed height
Out of square 1.5° or less
[Limit]
Free height -1.0 mm (-0.039 inch)
Out of square 4°
Valve Guides
Check the valve stem-to-guide clearance. If the clearance exceeds the service limit, replace the valve guide with the next oversize part.
Valve stem-to-guide clearance
[Standard dimension]
Intake 0.020 - 0.047 mm (0.0008 - 0.0019 inch)
Exhaust 0.050 - 0.085 mm (0.0020 - 0.0033 inch)
[Limit]
Intake 0.1 mm (0.0040 inch)
Exhaust 0.15 mm (0.0059 inch)
Valve Seat Insert
Check the valve seat for overheating and improper contact with the valve face. Recondition or replace the seat if necessary.
Before reconditioning the seat, check the valve guide for wear. If the valve guide is worn, replace it, and then recondition the seat. Recondition the valve seat with a valve seat grinder or cutter. The valve seat contact width should be within specifications and centered on the valve face.
Procedures for Replacing Valve Seat Insert
1. Any valve seat insert that has been worn over the service limit should be removed at normal temperature after cutting away most of the insert wall using valve seat cutters as shown in Fig. "A".
2. After removing the seat insert, machine the seat insert bore using a reamer or a cutter. Cut to the size shown in the table.
3. Heat the cylinder head to about 250°C (480°F) and press in the oversize seat insert. The oversize seat insert should be at normal room temperature for installation. After installing a new valve seat insert, resurface the valve seat using the same procedure as in "Valve Seat Insert".
Valve Seat Insert Oversizes
Procedures for Replacing Valve Guide
The valve guide is installed by using a press fit. Using a Valve Guide Installer (09222-21200 A/B and 09222-28400) or suitable tool, replace the valve guide according to the following procedure.
1. Using the push rod of the Valve Guide Installer, push the valve guide out toward the cylinder block with a press.
2. Machine the valve guide insert hole in the cylinder head to the specified oversize of the new valve guide.
3. Using the Valve Guide Installer or suitable tool, press fit the valve guide. The use of the valve guide installer makes it possible to press fit the valve guide to a predetermined height. The valve guide should be installed from the top of the cylinder head. Note that intake and exhaust valve guides are different in length [45.5 mm (1.791 inch) for intake and 50.5 mm (1.988 inch) for exhaust.]
4. After the valve guides have been installed, insert new valves and check the clearance.
5. Whenever valve guides are replaced, check that the valve is seated in contact with then and recondition the valve seats as necessary.
Valve Guide Oversizes
INSTALLATION
NOTE:
1) Clean each part before assembly.
2) Apply engine oil to sliding and rotating parts.
1. After installing the spring seat, fit the stem seal onto the valve guide.
Fit the seal in by lightly tapping the Special Tool, Valve Stem Oil Seal Installer.
The seal is installed in the specified position by means of the special tool. Incorrect installation of the seal will adversely affect the lip I.D. and eccentricity, resulting in oil leakage down the valve guides. When installing, therefore, be careful not to twist the seal. Do not reuse old stem seals.
2. Apply engine oil to each valve. Insert the valves into the valve guides. Avoid inserting the valve into the seal by force.
After inserting, check that the valve moves smoothly.
3. Install springs and spring retainers.
Valve springs should be installed with the enamel coated side toward the valve spring retainer.
4. Using the special tool, Valve Spring Compressor (09221-29100) remove the retainer lock. Next remove the spring retainer, valve spring, spring seat and valve.
NOTE: Keep these parts so that they can be reinstalled in their original positions.
5. Clean all gasket surfaces of the cylinder block and cylinder head.
6. Install a new cylinder head gasket onto the cylinder head assembly. Do not apply sealant to the gasket and do not reuse the old cylinder head gasket.
Cylinder Head Tightening Sequence:
7. Install the cylinder head bolts as shown in the illustration.
NOTE:
Check and measure the length of bolt.
Maximum length: 99.4 ±0.35 mm (3.9 inch)
8. Tighten the bolts according to the following procedure.
Procedures for Installing Cylinder Head (With Replacing Head Bolts)
Procedures for installing cylinder head (Without replacing head bolts)
