Cylinder Head Inspection/Repair
CYLINDER HEAD INSPECTION/REPAIR1. Carry out color contrast penetrant examination on the cylinder head surface. Replace the cylinder head if necessary.
2. Inspect for the following and repair or replace if necessary.
1. Sunken valve seats
2. Excessive camshaft oil clearance and end play
3. Measure the cylinder head for distortion in the six directions as shown.
- If the cylinder head distortion exceeds the maximum, repair by grinding the surface or replace the cylinder head.
- If the cylinder head height is out of specification, replace as necessary.
Distortion 0.06 mm (0.0024 inch) max.
Standard height 120.23 - 120.43 mm (4.7335 - 4.7413 inch)
Grinding 0.20 mm (0.008 inch) max.
4. Measure the manifold contact surface distortion as shown. If the distortion exceeds the maximum, grind the surface or replace the cylinder head.
Distortion 0.05 mm (0.0019 inch) max.
Grinding 0.20 mm (0.008 inch) max.
Valve, Valve Guide Inspection
1. Measure the valve head margin thickness of each valve.
- If it is out of specification, replace as necessary.
Margin thickness
IN: 1.10 mm (0.043 inch)
EX: 1.20 mm (0.047 inch)
2. Measure the length of each valve.
- If the valve length is less than minimum, replace as necessary.
Standard length
IN: 90.78 - 91.38 mm (3.575 - 3.597 inch)
EX: 90.27 - 90.87 mm (3.554 - 3.577 inch)
Minimum length
IN: 90.58 mm (3.566 inch)
EX: 90.07 mm (3.546 inch)
3. Measure the stem diameter of each valve in X a Y directions at the three points (A, B, and C) shown.
- If the valve stem diameter is less than minimum, replace as necessary.
Standard diameter
IN: 5.970 - 5.985 mm (0.2351 - 0.2356 inch)
EX: 5.965 - 5.980 mm (0.2349 - 0.2354 inch)
Minimum diameter
IN: 5.920 mm (0.2331 inch)
EX: 5.915 mm (0.2329 inch)
4. Measure the inner diameter of each valve guide in X and Y directions at the three points (A, B, and C) shown.
- If it is out of specification, replace as necessary.
Standard Inner diameter
Standard: 6.01 - 6.03 mm (0.2367 - 0.2374 inch)
Oversize: 6.02 - 6.04 mm (0.2371 - 0.2377 inch)
5. Measure the protrusion height (dimension A) of each valve guide without lower valve spring seat.
- If it is out of specification, replace as necessary.
Standard height 13.5 - 14.1 mm (0.532 - 0.555 inch)
Valve Guide Replacement
Valve Guide Removal
- Remove the valve guide from the combustion chamber side using the SST.
Valve Guide Installation
1. Assemble the SSTs so that depth L is as specified.
Depth L 13.5 - 14.1 mm (0.532 - 0.555 inch)
2. Tap the valve guide in from the side opposite the combustion chamber until the SSTs contacts the cylinder head.
3. Verify that the valve guide projection height (dimension) is within the specification.
Standard height 13.5 - 14.1 mm (0.532 - 0.555 inch)
Valve Seat Inspection/Repair
1. Measure the seat contact width.
- If necessary, resurface the valve seat using a 45° valve seat cutter and/or resurface the valve face.
Standard width 0.8 - 1.4 mm (0.032 - 0.055 inch)
2. Verify that the valve seating position is at the center of the valve face.
- If the seating position is too high, correct the valve seat using a 80° cutter, and a 45° cutter.
- If the seating position is too low, correct the valve seat using a 35° (IN) or 30° (EX) cutter, and a 45° cutter.
3. Inspect the sinking of the valve seat. Measure the protruding length (dimension L) of the valve stem. If it is out of specification, replace as necessary.
Standard dimension L 38.7 mm (1.524 inch)
Valve Spring Inspection
1. Apply pressing force to the pressure spring and inspect the spring height.
- If it is out of specification, replace as necessary.
Pressing force 126.4 - 142.9 N (12.88 - 14.58 kgf, 28.34 - 32.07 lbf)
Standard height 36.5 mm (1.44 inch)
2. Measure the out-of-square of the valve spring.
- If it is out of specification, replace as necessary.
Valve spring out-of-square 1.53 mm (0.060 inch) max.
Camshaft Inspection
1. Set the No. 1 and No.5 journals on V-blocks. Measure the camshaft runout.
- If it is out of specification, replace as necessary.
Runout 0.03 mm (0.0012 inch) max.
2. Measure the cam lobe height at the two points as shown.
- If the cam lobe height is less than specification, replace as necessary.
Standard height
IN: 41.354 mm (1.6281 inch)
EX: 40.900 mm (1.6102 inch)
Minimum height
IN: 41.154 mm (1.6202 inch)
EX: 40.700 mm (1.6024 inch)
3. Measure the journal diameters in X and Y directions at the two points (A and B) as shown.
- If the journal diameter is less than specification, replace as necessary.
Standard diameter 25.940 - 25.965 mm (1.0213 - 1.0222 inch)
Minimum diameter 25.910 mm (1.0201 inch)
4. With the tappets and shims removed, measure the camshaft journal oil clearances as follows.
1. Position plastigage atop the journals in the axial direction.
2. Do not rotate the camshaft when measuring the oil clearances.
3. Install the camshaft caps. Refer to Engine; Service and Repair; Engine Disassembly/Assembly.
4. Remove the camshaft caps. Refer to Engine; Service and Repair; Engine Disassembly/Assembly.
5. Measure the oil clearance.
- If it is out of specification, replace the cylinder head and/or camshaft cap.
Oil clearance: 0.035 - 0.081 mm (0.0014 - 0.0031 inch)
5. Install the camshaft cap. Refer to Engine; Service and Repair; Engine Disassembly/Assembly.
6. Measure the camshaft end play.
- If the camshaft end play exceeds the maximum, replace the cylinder head and/or camshaft.
Standard end play 0.07 - 0.19 mm (0.0028 - 0.0074 inch)
Maximum end play 0.20 mm (0.008 inch)
7. Remove the camshaft cap. Refer to Engine; Service and Repair; Engine Disassembly/Assembly.
Tappet Inspection
1. Measure the diameter of each tappet bore.
Standard diameter 30.000 - 30.025 mm (1.1811 - 1.1820 inch)
2. Measure the diameter of each tappet.
Standard diameter 29.959 - 29.975 mm (1.1795 - 1.1801 inch)
3. Calculate the clearance between the tappet and the related tappet bore.
- If the clearance is exceeds the maximum, replace the tappet and/or cylinder head.
Standard clearance 0.025 - 0.066 mm (0.00099 - 0.00259 inch)
Maximum clearance 0.180 mm (0.00711 inch)