Valves and Valve Springs
REMOVAL
1. Using 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 in order so that they can be reinstalled in their original positions.
2. Remove the valve stem seals using special tool (09222-29000) and discard it.
NOTE: Do not reuse the valve stem seals.
INSPECTION
Valves
1. Using a wire brush, clean the valve thoroughly.
2. Check each valve for wear, damage and distortion of head and stem [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 1.15 mm (0.045 inch)
Exhaust 1.35 mm (0.053 inch)
[Limit]
Intake 0.8 mm (0.031 inch)
Exhaust 1.0 mm (0.039 inch)
Valve Springs
1. Check the valve spring free length and tension. 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 46.07 mm (1.814 inch)
Load 25.5 kg at 37 mm 57.3kg at 28 mm
Out of square 1.5° or less
Valve Guides
Check the valve stem-to-guide clearance. If the clearance exceeds the service limit, replace the valve guide with next oversize part.
Valve stem-to-guide clearance
[Standard dimension]
Intake 0.02 - 0.05 mm (0.001 - 0.002 inch)
Exhaust 0.05 - 0.085 mm (0.002 - 0.003 inch)
[Limit]
Intake 0.1 mm (0.004 inch)
Exhaust 0.15 mm (0.006 inch)
Valve Guide Oversizes
Valve Seat Insert
Check the valve seat for evidence of 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, 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.
Valve Seat Insert Replacement Procedure
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.
Valve Seat Insert Oversizes
Valve Guide Replacement Procedures
The valve guide is installed using a press fit. Using a Valve Guide Installer (09221-22001 or suitable tool, replace the valve guide by 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 adaptor (09222-29000) and 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 the intake and exhaust valve guides are different in length [42.7 mm (1.68 inch) for intake and 39.1 mm (1.54 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 for valve to seat contact and recondition the valve seats as necessary.
INSTALLATION
CAUTION:
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.
To install, fit the seal in by lightly tapping the Special Tool, Valve Stem Oil Seal Installer (09222-22001).
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 stem. Insert the valves into the valve guides. Avoid inserting the valve into the seal with force. After insertion, check to see if 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 Special Tool, Valve Spring Compressor (09221-29100) compress the spring. Be careful that the valve stem seal is not distorted by the bottom of the retainer. Then install the retainer locks. After installation of the valves, make certain that the retainer locks are properly installed.
5. Install the cylinder head.