2ZR-FAE (ENGINE MECHANICAL): CYLINDER HEAD: INSPECTION; 2020 - 2023 MY Corolla [01/2019

Last Modified: 05-13-2024	6.11:8.1.0	Doc ID: RM100000001G45Z
Model Year Start: 2020	Model: Corolla	Prod Date Range: [01/2019 - 11/2022]
Title: 2ZR-FAE (ENGINE MECHANICAL): CYLINDER HEAD: INSPECTION; 2020 - 2023 MY Corolla [01/2019 - 11/2022]

INSPECTION

PROCEDURE

1. INSPECT CYLINDER HEAD SUB-ASSEMBLY FOR WARPAGE

(a) Using a precision straightedge and feeler gauge, check the surfaces which contact the cylinder head sub-assembly and manifold for warpage.

Maximum Warpage:

Item	Specified Condition
Bottom side	0.05 mm (0.00197 in.)
Intake manifold side	0.10 mm (0.00394 in.)
Exhaust manifold side	0.10 mm (0.00394 in.)

HINT:

If the warpage is more than the maximum, replace the cylinder head sub-assembly.

*a	Bottom Side
*b	Intake Manifold Side
*c	Exhaust Manifold Side

2. INSPECT CYLINDER HEAD SUB-ASSEMBLY FOR CRACKS

(a) Using a dye penetrant, check the intake ports, exhaust ports and bottom surface of the cylinder head sub-assembly for cracks.

HINT:

If cracks are found, replace the cylinder head sub-assembly.

3. INSPECT VALVE SEATS

(a) Apply a light coat of Prussian blue to the valve face.

Width

(b) Lightly press the valve face against the valve seat.

NOTICE:

Do not rotate the valve while pressing it.

(1) If Prussian blue appears 360° around the entire valve face, the valve face is concentric.

HINT:

If the valve face is not concentric, replace the valve.

(2) If Prussian blue appears 360° around the entire valve seat, the valve seat and valve face are concentric.

HINT:

If the valve face is not concentric, resurface the valve seat.

Click here

(3) Measure the width of the contact area of the valve seat and valve face.

Standard Width:

Item	Specified Condition
Intake	1.0 to 1.4 mm (0.0394 to 0.0551 in.)
Exhaust	1.0 to 1.4 mm (0.0394 to 0.0551 in.)

4. INSPECT INNER COMPRESSION SPRING

(a) Using a vernier caliper, measure the free length of the inner compression spring.

Standard Free Length (New parts):

51.88 mm (2.042 in.)

HINT:

If the free length is not as specified, replace the inner compression spring.

(b) Using a steel square, measure the deviation of the inner compression spring.

Maximum Deviation:

1.3 mm (0.0512 in.)

HINT:

If the deviation is greater than the maximum, replace the inner compression spring.

*a	Deviation
*b	37.5 mm (1.48 in.)

5. INSPECT INTAKE VALVE

(a) Using a vernier caliper, measure the overall length of the intake valve.

Standard Overall Length:

109.34 mm (4.30 in.)

Minimum Overall Length:

108.84 mm (4.29 in.)

HINT:

If the overall length is less than the minimum, replace the intake valve.

*a	Overall length

(b) Using a micrometer, measure the diameter of the valve stem.

Standard Valve Stem Diameter:

5.470 to 5.485 mm (0.215 to 0.216 in.)

HINT:

If the valve stem diameter is not as specified, check the intake valve guide bush oil clearance.

Click here

Standard Margin Thickness:

1.0 mm (0.0394 in.)

Minimum Margin Thickness:

0.5 mm (0.0197 in.)

HINT:

If the margin thickness is less than the minimum, replace the intake valve.

*a	Margin thickness

6. INSPECT EXHAUST VALVE

(a) Using a vernier caliper, measure the overall length of the exhaust valve.

Standard Overall Length:

108.25 mm (4.26 in.)

Minimum Overall Length:

107.75 mm (4.24 in.)

HINT:

If the overall length is less than the minimum, replace the exhaust valve.

*a	Overall length

(b) Using a micrometer, measure the diameter of the exhaust valve stem.

Standard Valve Stem Diameter:

5.465 to 5.480 mm (0.215 to 0.216 in.)

HINT:

If the valve stem diameter is not as specified, check the exhaust valve guide bush oil clearance.

Click here

Standard Margin Thickness:

1.0 mm (0.0394 in.)

Minimum Margin Thickness:

0.5 mm (0.0197 in.)

HINT:

If the margin thickness is less than the minimum, replace the exhaust valve.

*a	Margin thickness

7. INSPECT VALVE GUIDE BUSH OIL CLEARANCE

(a) Using a caliper gauge, measure the inside diameter of the valve guide bush.

Standard Valve Guide Bush Inside Diameter:

5.510 to 5.530 mm (0.217 to 0.218 in.)

(b) Subtract the valve stem diameter measurement from the valve guide bush inside diameter measurement.

Standard Oil Clearance:

Item	Specified Condition
Intake	0.025 to 0.060 mm (0.000984 to 0.00236 in.)
Exhaust	0.030 to 0.065 mm (0.00118 to 0.00256 in.)

Maximum Oil Clearance:

Item	Specified Condition
Intake	0.080 mm (0.00315 in.)
Exhaust	0.085 mm (0.00335 in.)

HINT:

Oil clearance = Inside diameter - Valve stem diameter
If the oil clearance is more than the maximum, replace the valve and valve guide bush.