Cylinder Head: Inspection

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INSPECT CYLINDER HEAD FOR WARPAGE
1. Using a precision straightedge and feeler gauge, measure the warpage of the contact surfaces of the cylinder block and manifolds.
  Maximum warpage: 0.08 mm (0.0032 in.)
  
  If the warpage is greater than the maximum, replace the cylinder head sub-assembly.
  
  Fig 1: Inspecting Cylinder Head For Warpage
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT CYLINDER HEAD FOR CRACKS
1. Using a dye penetrant, inspect the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks.
  If cracked, replace the cylinder head.
  
  Fig 2: Inspecting Cylinder Head For Cracks
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT VALVE SEAT

Apply a light coat of Prussian blue to the valve face.
Lightly press the valve against the seat.
NOTE: Do not turn the valve.

Check the valve face and seat in accordance with the following procedure.

If blue appears 360° around the face, the valve is concentric. If not, replace the valve.
If blue appears 360° around the valve seat, the guide and face are concentric. If not, resurface the valve seat (see REPAIR ).

Check that the seat contact is in the middle of the valve face with a width.

Standard width

STANDARD WIDTH SPECIFICATION

Item	Standard Condition
Intake	1.0 to 1.4 mm (0.0039 to 0.0551 in.)
Exhaust	1.2 to 1.6 mm (0.0472 to 0.0630 in.)

Fig 3: Checking Seat Contact In Middle Of Valve Face With Width

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT CAMSHAFT TIMING GEAR ASSEMBLY
1. Check the lock of the camshaft timing gear.
  1. Clamp the camshaft in a vise, and confirm that the camshaft timing gear is locked.
    NOTE: Be careful not to damage the camshaft.
2. Release the lock pin.
  1. Cover the 4 oil paths of the cam journal with vinyl tape as shown in the illustration.
    HINT:
    
    The 2 advance side paths are provided in the groove of the camshaft. Plug one of the paths with a rubber piece.
  2. Break through the tape of the advance side path and the retard side path on the opposite side of the groove.
    
    Fig 4: Inspecting Camshaft Timing Gear
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Apply approximately 200 kPa (2.0 kgf/cm² , 28 psi) of air pressure to the paths whose tape was broken in the procedure above.
    CAUTION: Some oil spraying will occur. Contain the spray with a shop rag.
    
    Fig 5: Applying Air Pressure Retard And Advance Side Path
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Check that the camshaft timing gear revolves in the advance direction when weakening the air pressure of the retard side path.
    OK: Gear rotates in advance direction.
    
    HINT:
    
    This operation releases the lock pin for the extreme retard position.
  5. When the camshaft timing gear reaches the extreme advance position, remove the air gun from the retard side path and advance side path, in that order.
    NOTE: Do not remove the air gun from the advance side path first. The gear may abruptly shift in the retard direction and break the lock pin.
3. Check for smooth rotation.
  1. Rotate the camshaft timing gear within its movable range several times, but do not turn it to the extreme retard position. Check that the gear rotates smoothly.
    OK: Gear rotates smoothly.
    
    NOTE: Do not use an air gun to perform the smooth operation check.
4. Check the lock in the extreme retard position.
  1. Confirm that the camshaft timing gear is locked at the extreme retard position.

INSPECT CAMSHAFT

Inspect the camshaft for runout.
1. Place the camshaft on V-blocks.
2. Using a dial indicator, measure the circle runout at the center journal.
  Maximum circle runout: 0.03 mm (0.0012 in.)
  
  If the circle runout is greater than the maximum, replace the camshaft.
  
  Fig 6: Measuring Circle Runout At Center Journal
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Inspect the cam lobes.
1. Using a micrometer, measure the cam lobe height.
  Standard cam lobe height: 47.306 to 47.406 mm (1.8624 to 1.8664 in.)
  
  Minimum cam lobe height: 47.196 mm (1.8581 in.)
  
  If the cam lobe height is less than the minimum, replace the camshaft.
  
  Fig 7: Measuring Cam Lobe Height
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Inspect the camshaft journals.

Using a micrometer, measure the journal diameter.

Standard journal diameter

STANDARD JOURNAL DIAMETER

Journal Position	Specified Condition
No. 1	35.971 to 35.985 mm (1.4162 to 1.4167 in.)
Other	22.959 to 22.975 mm (0.9039 to 0.9045 in.)

Fig 8: Inspecting Camshaft Journals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If the journal diameter is not as specified, check the oil clearance.

INSPECT NO. 2 CAMSHAFT

Inspect the camshaft for runout.
1. Place the camshaft on V-blocks.
2. Using a dial indicator, measure the circle runout at the center journal.
  Maximum circle runout: 0.03 mm (0.0012 in.)
  
  If the circle runout is greater than the maximum, replace the No. 2 camshaft.
  
  Fig 9: Inspecting Camshaft For Runout
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Inspect the cam lobes.
1. Using a micrometer, measure the cam lobe height.
  Standard cam lobe height: 45.983 to 46.083 mm (1.8104 to 1.8143 in.)
  
  Minimum cam lobe height: 45.873 mm (1.8060 in.)
  
  If the cam lobe height is less than the minimum, replace the No. 2 camshaft.
  
  Fig 10: Inspecting Cam Lobes
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Inspect the camshaft journals.

Using a micrometer, measure the journal diameter.

Standard journal diameter

STANDARD JOURNAL DIAMETER

Journal Position	Specified Condition
No. 1	35.971 to 35.985 mm (1.4162 to 1.4167 in.)
Other	22.959 to 22.975 mm (0.9039 to 0.9045 in.)

Fig 11: Inspecting Camshaft Journals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If the journal diameter is not as specified, check the oil clearance.

INSPECT CAMSHAFT OIL CLEARANCE

Clean the 10 bearing caps and camshaft journals.
Place the 2 camshafts on the cylinder head.
Lay a strip of Plastigage across each of the camshaft journals.

Fig 12: Inspecting Camshaft Oil Clearance
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Install the 10 bearing caps (see appropriate step(s) under INSTALLATION ).
NOTE: Do not turn the camshaft.
Remove the 10 bearing caps for the No. 2 CAMSHAFT and CAMSHAFT , (see appropriate step(s) under REMOVAL ).

Measure the Plastigage at its widest point.

Standard oil clearance

STANDARD OIL CLEARANCE

Item	Standard Condition
Intake No. 1 journal	0.007 to 0.038 mm (0.0003 to 0.0015 in.)
Exhaust No. 1 journal	0.040 to 0.079 mm (0.0016 to 0.0031 in.)
Other journal	0.025 to 0.062 mm (0.0010 to 0.0024 in.)

Fig 13: Identifying Bearing Cap Number Mark

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Maximum oil clearance

MAXIMUM OIL CLEARANCE

Item	Standard Condition
Intake No. 1 journal	0.07 mm (0.0028 in.)
Other journal	0.10 mm (0.0039 in.)

NOTE: Completely remove the Plastigage after the measurement.

If the oil clearance on the No. 1 journal is greater than the maximum, choose a new bearing and install it.

If the oil clearance on the other journals is greater than the maximum, replace the cylinder head sub-assembly or the camshaft.

Standard cylinder head journal bore diameter

STANDARD CYLINDER HEAD JOURNAL BORE DIAMETER

Mark	Standard Condition
Mark 1	40.000 to 40.008 mm (1.5748 to 1.5751 in.)
Mark 2	40.009 to 40.017 mm (1.5752 to 1.5755 in.)
Mark 3	40.018 to 40.025 mm (1.5755 to 1.5758 in.)

Standard bearing center wall thickness

STANDARD BEARING CENTER WALL THICKNESS

Mark	Standard Condition
Mark 1	2.000 to 2.004 mm (0.0787 to 0.0789 in.)
Mark 2	2.005 to 2.008 mm (0.0789 to 0.0791 in.)
Mark 3	2.009 to 2.012 mm (0.0791 to 0.0792 in.)

Standard camshaft journal diameter: 35.971 to 35.985 mm (1.4162 to 1.4167 in.)

INSPECT CAMSHAFT THRUST CLEARANCE

Install the 2 camshafts (see appropriate step(s) under INSTALLATION ).

Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.

Standard thrust clearance

STANDARD THRUST CLEARANCE

Item	Standard Condition
Intake	0.040 to 0.095 mm (0.0016 to 0.0037 in.)
Exhaust	0.080 to 0.135 mm (0.0032 to 0.0053 in.)

Fig 14: Inspecting Camshaft Thrust Clearance

Maximum thrust clearance

MAXIMUM THRUST CLEARANCE

Item	Standard Condition
Intake	0.11 mm (0.0043 in.)
Exhaust	0.15 mm (0.0059 in.)

If the thrust clearance is greater than the maximum, replace the cylinder head.

If damage is found on the camshaft thrust surfaces, replace the camshaft.

INSPECT VALVE LIFTER
1. Using a micrometer, measure the lifter diameter.
  Standard lifter diameter: 30.966 to 30.976 mm (1.2191 to 1.2195 in.)
  
  If the diameter is not as specified, replace the valve lifter.
  
  Fig 15: Measuring Lifter Diameter
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT VALVE LIFTER OIL CLEARANCE
1. Using a caliper gauge, measure the valve lifter bore diameter of the cylinder head.
  Standard lifter bore diameter: 31.009 to 31.025 mm (1.2208 to 1.2215 in.)
  
  If the diameter is not as specified, replace the cylinder head sub-assembly.
2. Subtract the valve lifter diameter measurement from the valve lifter bore diameter measurement.
  Standard oil clearance: 0.033 to 0.059 mm (0.0013 to 0.0023 in.)
  
  Maximum oil clearance: 0.079 mm (0.0031 in.)
  
  Fig 16: Measuring Valve Lifter Bore Diameter Of Cylinder Head
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  If the oil clearance is greater than the maximum, replace the valve lifter. If necessary, replace the cylinder head sub-assembly.
INSPECT INNER COMPRESSION SPRING
1. Using a vernier caliper, measure the free length of the valve spring.
  Standard free length: 47.43 mm (1.8673 in.)
  
  If the length is not as specified, replace the inner compression spring.
  
  Fig 17: Measuring Free Length Of Valve Spring
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using a steel square, measure the deviation of the inner compression spring.
  Maximum deviation: 1.6 mm (0.063 in.)
  
  Maximum angle (Reference): 2°
  
  If the deviation is greater than the maximum, replace the inner compression spring.
  
  Fig 18: Measuring Deviation Of Inner Compression Spring
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT INTAKE VALVE
1. Using a gasket scraper, chip off any carbon on the valve head.
2. Using a wire brush, thoroughly clean the valve.
  
  Fig 19: Cleaning Valve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Using a vernier caliper, measure the valve overall length.
  Standard overall length: 101.71 mm (4.0043 in.)
  
  Minimum overall length: 101.21 mm (3.9846 in.)
  
  If the overall length is less than the minimum, replace the intake valve.
  
  Fig 20: Measuring Valve Overall Length
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Using a micrometer, measure the diameter of the valve stem.
  Standard valve stem diameter: 5.470 to 5.485 mm (0.2154 to 0.2159 in.)
  
  If the diameter is not as specified, replace the intake valve.
  
  Fig 21: Measuring Diameter Of Valve Stem
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Using a vernier caliper, measure the valve head margin thickness.
  Standard margin thickness: 1.25 mm (0.0492 in.)
  
  Minimum margin thickness: 1.05 mm (0.0413 in.)
  
  If the diameter is not as specified, replace the intake valve.
  
  Fig 22: Measuring Valve Head Margin Thickness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT EXHAUST VALVE
1. Using a gasket scraper, chip off any carbon on the valve head.
2. Using a wire brush, thoroughly clean the valve.
  
  Fig 23: Cleaning Valve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Using a vernier caliper, measure the valve overall length.
  Standard overall length: 101.15 mm (3.9823 in.)
  
  Minimum overall length: 100.70 mm (3.9646 in.)
  
  If the overall length is less than the minimum, replace the exhaust valve.
  
  Fig 24: Measuring Valve Overall Length
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Using a micrometer, measure the diameter of the valve stem.
  Standard valve stem diameter: 5.465 to 5.480 mm (0.2152 to 0.2158 in.)
  
  If the overall length is less than the minimum, replace the exhaust valve.
  
  Fig 25: Measuring Diameter Of Valve Stem
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Using a vernier caliper, measure the valve head margin thickness.
  Standard margin thickness: 1.40 mm (0.0551 in.)
  
  Minimum margin thickness: 1.20 mm (0.0472 in.)
  
  If the overall length is less than the minimum, replace the exhaust valve.
  
  Fig 26: Measuring Valve Head Margin Thickness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT INTAKE VALVE GUIDE BUSH
1. Using a caliper gauge, measure the inside diameter of the guide bush.
  Standard bush inside diameter: 5.510 to 5.530 mm (0.2169 to 0.2177 in.)
  
  If the inside diameter is not as specified, replace the intake valve guide bush.
2. Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.
  Standard oil clearance: 0.025 to 0.060 mm (0.0010 to 0.0024 in.)
  
  Maximum oil clearance: 0.08 mm (0.0032 in.)
  
  If the clearance is greater than the maximum, replace the valve and intake guide bush.
  
  Fig 27: Measuring Inside Diameter Of Guide Bush
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT EXHAUST VALVE GUIDE BUSH
1. Using a caliper gauge, measure the inside diameter of the guide bush.
  Standard bush inside diameter: 5.510 to 5.530 mm (0.2169 to 0.2177 in.)
  
  If the inside diameter is not as specified, replace the exhaust valve guide bush.
2. Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.
  Standard oil clearance: 0.030 to 0.065 mm (0.0012 to 0.0026 in.)
  
  Maximum oil clearance: 0.10 mm (0.004 in.)
  
  If the clearance is greater than the maximum, replace the valve and exhaust valve guide bush.
  
  Fig 28: Inspecting Exhaust Valve Guide Bush
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT CYLINDER HEAD SET BOLT
1. Using a vernier caliper, measure the length of the head bolts from the seat to the end.
  Standard bolt length: 141.3 to 142.7 mm (5.563 to 5.618 in.)
  
  Maximum bolt length: 144.2 mm (5.677 in.)
  
  If the bolt length is greater than the maximum, replace the cylinder head set bolt.
  
  Fig 29: Measuring Length Of Head Bolts
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT EXHAUST MANIFOLD
1. Using a precision straightedge and a feeler gauge, measure the surface contacting the cylinder head for warpage.
  Maximum warpage: 0.70 mm (0.028 in.)
  
  If the warpage is greater than the maximum, replace the exhaust manifold.
  
  Fig 30: Inspecting Exhaust Manifold Flange
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002