Inspection

CYLINDER HEAD


Inspection After Disassembly


VALVE DIMENSIONS
- Check dimensions of each valve. For dimensions, refer to Specifications.
- If dimensions are out of the standard, replace valve.

VALVE GUIDE CLEARANCE

Valve Stem Diameter
Measure the diameter of valve stem with a micrometer (A).











Valve Guide Inner Diameter
Measure the inner diameter of valve guide with a bore gauge.

Standard : 5.500 - 5.518 mm (0.2165 - 0.2172 in)


Valve Guide Clearance
(Valve guide clearance) = (Valve guide inner diameter) � (Valve stem diameter).





- If it exceeds the limit, replace valve guide and/or valve.

VALVE GUIDE REPLACEMENT
When valve guide is removed, replace with oversized [0.2 mm (0.008 in)] valve guide.





1. To remove valve guide, heat cylinder head to 110� to 130�C (230� to 266�F) by soaking in heated oil (A).





2. Drive out valve guide using suitable tools.

WARNING:
Cylinder head contains heat, when working, wear protective equipment to avoid getting burned.





3. Ream cylinder head valve guide hole using suitable tool (A).










4. Heat cylinder head to 110� to 130�C (230� to 266�F) by soaking in heated oil (A).
5. Press valve guide (1) from camshaft side to dimensions as shown.





2 : Cylinder head

Projection (H) : 13.35 - 13.65 mm (0.526 - 0.537 in)


WARNING:
Cylinder head contains heat, when working, wear protective equipment to avoid getting burned.





6. Apply reamer finish to valve guide using suitable tool (A).

Standard : 5.500 - 5.518 mm (0.2165 - 0.2172 in)


VALVE SEAT CONTACT
- After confirming that the dimensions of valve guides and valves are within specifications, perform this procedure.
- Apply prussian blue (or white lead) onto contacting surface of valve seat to check the condition of the valve contact on the surface.





- Check if the contact area band is continuous all around the circumference.
- If not, grind to adjust valve fitting and check again. If the contacting surface still has NG conditions even after the re-check, replace valve seat.

VALVE SEAT REPLACEMENT
When valve seat is removed, replace with oversized [0.5 mm (0.020 in)] valve seat.
1. Bore out old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess in cylinder head. Set the machine depth stop to ensure this. Refer to Specifications.





2. Ream cylinder head (1) recess diameter for service valve seat.

2 : Valve seat





- Be sure to ream in circles concentric to the valve guide center.
This will enable valve seat to fit correctly.





3. Heat cylinder head to 110� to 130�C (230� to 266�F) by soaking in heated oil (A).
4. Provide valve seats cooled well with dry ice. Press-fit valve seat into cylinder head.

WARNING:
- Never touch cold valve seats directly.
- Cylinder head contains heat, when working, wear protective equipment to avoid getting burned.





5. Using valve seat cutter set or valve seat grinder, finish valve seat to the specified dimensions. For dimensions, refer to Specifications.

CAUTION:
When using valve seat cutter, firmly grip the cutter handle with both hands. Then, press on the contacting surface all around the circumference to cut in a single drive. Improper pressure on the cutter or cutting many different times may result in staged valve seat.
6. Using compound, grind to adjust valve fitting.
7. Check again for normal contact.

VALVE SPRING SQUARENESS
- Set try square along the side of valve spring and rotate the spring.





Measure the maximum clearance between the top of valve spring and try square.

CAUTION:
Never remove valve spring seat from valve spring.

Limit: 1.9 mm (0.075 in)

- If it exceeds the limit, replace valve spring (with valve spring seat).

VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD
- Check valve spring pressure with valve spring seat installed at the specified spring height.






CAUTION:
Never remove valve spring seat from valve spring.





- If the installation load or load with valve open is out of the standard, replace valve spring (with valve spring seat).