Cylinder Head Assembly: Testing and Inspection
Inspection
CYLINDER HEAD DISTORTION
Head surface flatness:.....Less than 0.1 mm (0.004 inch)
If beyond the specified limit, resurface it or replace it.
The resurfacing limit of cylinder head is determined by the cylinder block resurfacing in an engine.
Resurfacing limit:
Amount of cylinder head resurfacing is "A".
Amount of cylinder block resurfacing is "B".
The maximum limit is as follows:.....A + B = 0.2 mm (0.008 inch)
After resurfacing cylinder head, check that camshaft rotates freely by hand. If resistance is felt, cylinder head must be replaced.
Nominal cylinder head height:1.....06.8 - 107.2 mm (4.205 - 4.220 inch)
Inspection
CAMSHAFT VISUAL CHECK
Check camshaft for scratches, seizure and wear.
Inspection
CAMSHAFT RUNOUT
1. Measure camshaft runout at the center journal.
Runout (Total indicator reading):.....Limit 0.1 mm (0.004 inch)
2. If it exceeds the limit, replace camshaft.
Inspection
CAMSHAFT CAM HEIGHT
1. Measure camshaft cam height.
Standard cam height:
Intake and exhaust:......38.943 - 39.133 mm (1.5332 - 1.5407 inch)
Cam wear limit:.....0.15 mm (0.0059 inch)
2. If wear is beyond the limit, replace camshaft.
Inspection
CAMSHAFT JOURNAL CLEARANCE
1. Measure outer diameter of camshaft journal.
Standard outer diameter:
A......46.920 - 46.940 mm (1.8472 - 1.8480 inch)
B......42.420 - 42.440 mm (1.6701 - 1.6709 inch)
C......47.920 - 47.940 mm (1.8866 - 1.8874 inch)
2. Measure inner diameter of camshaft bearing.
Standard inner diameter:
A.......47.000 - 47.025 mm (1.8504 - 1.8514 inch)
B.......42.500 - 42.525 mm (1.6732 - 1.6742 inch)
C.......48.000 - 48.025 mm (1.8898 - 1.8907 inch)
3. If clearance exceeds the limit, replace camshaft and/or cylinder head.
Camshaft journal clearance limit: 0.15 mm (0.0059 inch)
Inspection
CAMSHAFT END PLAY
1. Install camshaft and locate plate in cylinder head.
2. Measure camshaft end play.
Camshaft end play:
Standard:.....0.03 - 0.06 mm (0.0012 - 0.0024 inch)
3. If it is out of the specified range, select thickness of camshaft locate plate to obtain standard specified end play.
Example:
When camshaft end play is 0.08 mm (0.0031 inch) with camshaft locate plate 1 replace camshaft locate plate 1 with camshaft locate plate 4 to set the end play at 0.04 mm (0.0016 inch).
Inspection
CAMSHAFT SPROCKET RUNOUT
1. Install sprocket on camshaft.
2. Measure camshaft sprocket runout.
Runout (Total indicator reading):
Limit:.....0.1 mm (0.004 inch)
3. If it exceeds the limit, replace camshaft sprocket.
Inspection
VALVE GUIDE CLEARANCE
1. Measure valve deflection in a right-angled direction with camshaft. (Valve and valve guide mostly wear in this direction.)
Valve deflection limit (Dial gauge reading):.....0.20 mm (0.0079 inch)
2. If it exceeds the limit, check valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diameter.
b. Check that clearance is within specification.
Valve to valve guide clearance:
Intake:.....0.020 - 0.053 mm (0.0008 - 0.0021 inch)
Exhaust:.....0.030 - 0.049 mm (0.0012 - 0.0019 inch)
Limit:.....0.10 mm (0.0039 inch)
c. If it exceeds the limit, replace valve or valve guide.
Inspection
VALVE SEATS
Check valve seats for any evidence of pitting at valve contact surface, and reseat or replace if it has worn out excessively.
Before repairing valve seats, check valve and valve guide for wear.
If they have worn, replace them. Then correct valve seat.
Use both hands to cut uniformly.
Inspection
VALVE DIMENSIONS
Check dimensions in each valve. Refer to Engine; Specifications; Mechanical.
When valve head has been worn down to 0.5 mm (0.020 inch) in margin thickness, replace valve.
Grinding allowance for valve stem tip is.....0.2 mm (0.008 inch) or less.
Inspection
VALVE SPRING
Squareness
1. Measure "S" dimension.
Out-of-square:
Outer:.....Less than 2.2 mm (0.087 inch)
Inner:.....Less than 1.9 mm (0.075 inch)
2. If it exceeds the limit, replace spring.
Pressure
Check valve spring pressure.
Standard pressure:
Outer:......523.7 N (53.4 kg, 117.7 lb) at 30.0 mm (1.181 inch)
Inner:......255.0 N (26.0 kg, 57.3 lb) at 25.0 mm (0.984 inch)
Limit pressure:
Outer:......More than 228.5 N (23.3 kg, 51.4 lb) at 25.0 mm (0.984 inch)
Inner:......More than 225.6 N (23.0 kg, 50.7 lb) at 25.0 mm (0.984 inch)
If not within specification, replace spring.
Inspection
ROCKER SHAFT AND ROCKER ARM
1. Check rocker shafts for scratches, seizure and wear.
2. Check outer diameter of rocker shaft.
Diameter:.....17.979 - 18.000 mm (0.7078 - 0.7087 inch)
3. Check inner diameter of rocker arm.
Diameter:......18.007 - 18.028 mm (0.7089 - 0.7098 inch)
Rocker arm to shaft clearance:.....0.007 - 0.049 mm (0.0003 - 0.0019 inch)
Keep rocker arm with hydraulic valve lifter standing to prevent air from entering hydraulic valve lifter when checking.
Inspection
HYDRAULIC VALVE LIFTER
1. Check contact and sliding surfaces for wear or scratches.
2. Check diameter of valve lifter.
Outer diameter:......15.947 - 15.957 mm (0.6278 - 0.6282 inch)
3. Check valve lifter guide inner diameter.
Inner diameter:.....16.000 - 16.013 mm (0.6299 - 0.6304 inch)
Standard clearance between valve lifter and lifter guide:......0.043 - 0.066 mm (0.0017 - 0.0026 inch)