Inspection After Disassembly

Inspection After Disassembly
CYLINDER HEAD DISTORTION





1. Wipe off oil and remove water scale (like deposit), gasket, sealer, carbon, etc. with scraper.

CAUTION: Use utmost care not to allow liquid gasket debris to enter passages for oil or water.

2. At each of several locations on bottom surface of cylinder head, measure distortion in six directions.
Limit: 0.1 mm (0.004 inch)

VALVE DIMENSIONS





^ Check dimensions of each valve. For dimensions, refer to "Valve Dimensions".

VALVE GUIDE CLEARANCE
Perform this inspection before removing valve guide.
1. Make sure that the valve stem diameter is within the specification.
2. Push the valve out by approximately 15 mm (0.59 inch) toward the combustion chamber side to measure the valve's run-out volume (in the direction of dial gauge) with dial gauge.
3. The half of the run-out volume accounts for the valve guide clearance.





Standard
Intake: 0.020 - 0.046 mm (0.0008 - 0.0018 inch)
Exhaust: 0.030 - 0.056 mm (0.0012 - 0.0022 inch)

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





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





2. Drive out valve guide with a press [under a 20 kN (2 ton, 2.2 US ton, 2.0 Imp ton) pressure] or hammer and suitable tool.

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





3. Ream cylinder head valve guide hole.
Valve guide hole diameter (for service parts)
Intake and exhaust: 10.175 - 10.196 mm (0.4006 - 0.4014 inch)
4. Heat cylinder head to 110 to 130°C (230 to 266°F) by soaking in heated oil.





5. Press valve guide from camshaft side to dimensions as in illustration.

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





6. Using valve guide reamer, apply reamer finish to valve guide.
Standard
Intake and exhaust: 6.000 - 6.018 mm (0.2362 - 0.2369 inch)

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 N.G 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 inch) 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.





2. Ream cylinder head recess diameter for service valve seat.
Oversize [0.5 mm (0.020 inch)]*
Intake: 37.500 - 37.516 mm (1.4764 - 1.4770 inch)
Exhaust: 32.700 - 32.716 mm (1.2874 - 1.2880 inch)
^ 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.
4. Provide valve seats cooled well with dry ice. Force fit valve seat into cylinder head.

CAUTION:
^ Avoid directly touching cold valve seats.
^ Cylinder head contains heat, when working wear protective equipment to avoid getting burned.





5. Using valve seat cutter set and valve seat grinder, finish the seat to the specified dimensions.

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 with the cutter or cutting many different times may result in stage valve seat.








^ Grind to obtain the dimensions indicated in figure.

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 face of spring and try square.
Limit: Less than 2.2 mm (0.087 inch)

VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD





Check valve spring pressure at specified spring height.
Standard: Free height 51.28 - 51.48 mm (2.0189 - 2.0268 inch)
Installation height 33.8 mm (1.331 inch)
Installation load 166 - 188 N (16.9 - 19.2 kg, 37 - 42 lbs.)
Height during valve open 24.4 mm (0.961 inch)
Load with valve open 291 - 372 N (29.7 - 37.9 kg, 65 - 83.6 lbs.)