Valve: Service and Repair
VALVE GUIDE REPLACEMENT PROCEDURE
Install the valve guide using a press fit. Using a Valve Guide Installer (09221-22000) or suitable tool, replace the valve guide using the following procedure.
1. Using the Valve Guide installer push rod, 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. Using the valve guide installer makes it possible to press fit the valve guide to a predetermined height. Install the valve guide from the top of the cylinder head. Note that intake and exhaust valve guides differ in length (42.7 mm [1.68 inch] for intake and 39.1 mm [1.54 inch] for exhaust).
4. After installing the valve guides, 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.
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.
Valve Seat Insert Oversizes
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 described in the first paragraph of "Valve Seat Insert".
DISASSEMBLY
1. 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 in order so they can be reinstalled in their original positions.
2. Remove the valve stem oil seals using the special tool, valve stem oil seal remover (09222-29000).
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 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 value:
Intake: 1.1 mm (0.0433 inch)
Exhaust: 1.3 mm (0.0512 inch)
Limit:
Intake: 0.8 mm (0.0391 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 (1.8137 inch)
Load:
25.5 kg at 37 mm
57.3 kg at 28 mm
Out of square: 3° 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 value:
Intake: 0.020-0.050 mm (0.0008-0.0019 inch)
Exhaust: 0.050-0.085 mm (0.0019-0.0033 inch)
Limit:
Intake: 0.1 mm (0.004 inch)
Exhaust: 0.15 mm (0.006 inch)
Valve Seat Insert
Check the valve seat for evidence of overheating and improper contact with the valve face. 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.
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.
To install, fit the seal in by lightly tapping the Special Tool, Valve Stem Oil Seal Installer (09222-22000).
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 leaking down the valve guides. Therefore, when installing, 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 using force when inserting the valve into the seal. 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.