Cylinder Head Assembly: Testing and Inspection
CYLINDER HEAD1. Inspect for flatness. Using a precision straight edge and feeler gauge, measure the surface the contacting the cylinder block and the manifolds for warpage.
Flatness of cylinder head gasket surface
Standard: Less than 0.03 mm (0.0012 in)
Limit: 0.05 mm (0.0020 in)
Flatness of manifold mating surface
Standard: Less than 0.15 mm (0.0059 in)
Limit: 0.20 mm (0.0079 in)
2. Inspect for cracks. Check the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks. If cracked, replace the cylinder head.
VALVE AND VALVE SPRING
1. Inspect the valve stems and valve guides.
A. Using a caliper gauge, measure the inner diameter of valve guide.
Valve guide inner diameter: 6.000 - 6.015 mm (0.2362 - 0.2368 in)
B. Using a micrometer, measure the outer diameter of valve stem.
Valve stem outer diameter
Intake: 5.965 - 5.980 mm (0.2348 - 0.2354 in)
Exhaust: 5.950 - 5.965 mm (0.2343 0.2348 in)
C. Subtract the valve stem outer diameter measurement from the valve guide inner diameter measurement.
Valve stem - to - guide clearance
Standard
Intake: 0.02 - 0.05 mm (0.0008 - 0.0020 in)
Exhaust: 0.035 - 0.065 mm (0.0014 0.0026 in)
Limit
Intake: 0.10 mm (0.0039 in)
Exhaust: 0.15 mm (0.0059 in)
If the clearance is greater than maximum, replace the valve and valve guide.
2. Inspect the valves.
A. Check the valve is ground to the correct valve face angle.
B. Check the surface of valve for wear. If the valve face is worn, replace the valve.
C. Check the valve head margin thickness. If the margin thickness is less than minimum, replace the valve.
Margin
Standard
Intake: 1.1 mm (0.0433 in)
Exhaust: 1.3 mm (0.0512 in)
Limit
Intake: 0.8 mm (0.0315 in)
Exhaust: 1.0 mm (0.0394 in)
D. Check the surface of valve stem tip for wear. If the valve stem tip is worn, replace the valve.
3. Inspect the valve seats.
A. Check the valve seat for evidence of overheating and improper contact with the valve face. Replace the seat if necessary.
B. Before reconditioning the seat, check the valve guide for wear. If the valve guide is worn, replace it, then recondition the seat.
C. 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.
4. Inspect the valve springs.
A. Using a steel square, measure the out-of-square of valve spring.
B. Using a vernier calipers, measure the free length of valve spring.
Valve spring
Standard
Free height: 44 mm (1.7323 in)
Load: 21.6 ± 1.1 kg/35.0 mm (47.6 ± 2.4 lb/1.3780 in) 45.1 ± 2.2 kg/27.2 mm (99.4 ± 4.9 lb/1.0709 in)
Out of square: Less than 1.5°
Limit Out of square: 3°
If the loads is not as specified, replace the valve spring.
CAMSHAFT
1. Inspect the cam lobes. Using a micrometer, measure the cam lobe height.
Cam height
Intake: 43.7492 - 43.9492 mm (1.72241 - 1.73028 in)
Exhaust: 44.1494 - 44.3494 mm (1.73816 1.74604 in)
If the cam lobe height is less than specified, replace the camshaft.
2. Inspect the camshaft journal clearance.
A. Clean the bearing caps and camshaft journals.
B. Place the camshafts on the cylinder head.
C. Lay a strip of plastigage across each of the camshaft journal.
D. Install the bearing caps and tighten the bolts with specified torque.
CAUTION: Do not turn the camshaft.
E. Remove the bearing caps.
F. Measure the plastigage at its widest point.
Bearing oil clearance
Standard: 0.020 - 0.061 mm (0.0008 - 0.0024 in)
Limit: 0.1 mm ( 0.0039 in)
If the oil clearance is greater than specified, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
G. Completely remove the plastigage.
H. Remove the camshafts.
3. Inspect the camshaft end play.
A. Install the camshafts.
B. Using a dial indicator, measure the end play while moving the camshaft back and forth.
Camshaft end play
Standard: 0.1 - 0.2 mm (0.0039 - 0.0079 in)
If the end play is greater than specified, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
C. Remove the camshafts.
CVVT (CONTINUOUS VARIABLE VALVE TIMING) ASSEMBLY
1. Inspect the CVVT (Continuous Variable Valve Timing) assembly.
A. Check that the CVVT (Continuous Variable Valve Timing) assembly will not turn.
B. Apply vinyl tape to all the parts except the one indicated by the arrow in the illustration.
C. Wrap tape around the tip of the air gun and apply air of approximately 98 kpa (1 kg/cm2, 14 psi) to the port of the camshaft. Perform this order to release the lock pin for the maximum delay angle locking.)
NOTE: Wrap around it with a shop rag and the likes, because the oil splashes.
D. Under the condition of 3), turn the CVVT assembly to the advance angle side with your hand.
^ Depending on the air pressure, the CVVT assembly will turn to the advance side.
^ If air is leaking from the port and air pressure cannot be maintained, the locking pin will not release.
E. Except the position where the lock pin meets at the maximum delay angle, let the CVVT assembly turn back and forth and check the movable range and that there is no disturbance.
Standard: Movable smoothly in the range about 20°
F. Turn the CVVT assembly with your hand and lock it at the maximum delay angle position.
HLA (HYDRAULIC LASH ADJUSTER)
With the HLA filled with engine oil, hold A and press B by hand. If B moves, replace the HLA.
