Cylinder Head Assembly: Testing and Inspection

2UZ-FE ENGINE MECHANICAL: CYLINDER HEAD:

INSPECTION

1. CLEAN CYLINDER HEAD SUB-ASSEMBLY

(a) Using a gasket scraper, remove all the gasket material from the cylinder block contact surface.

NOTE: Be careful not to scratch the cylinder block contact surface.

(b) Using a wire brush, remove all the carbon from the combustion chambers.

NOTE: Be careful not to scratch the cylinder block contact surface.

(d) Using a soft brush and solvent, thoroughly clean the cylinder head.
2. INSPECT CYLINDER HEAD SUB-ASSEMBLY

(a) Using a precision straightedge and feeler gauge, measure the surfaces contacting the cylinder block and manifolds for warpage.
Maximum warpage:

If the warpage is greater than the maximum, replace the cylinder head.

(b) Using a dye penetrant, check the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks.
If the cylinder head is cracked, replace it.
3. INSPECT INTAKE VALVE
(a) Clean the valves.

(1) Using a gasket scraper, chip off any carbon from the valve head.
(2) Using a wire brush, thoroughly clean the valve.

(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.)
(c) Check the valve face angle.

(1) Grind the valve sufficiently to remove pits and carbon.
(2) Check that the valve is ground to the correct valve face angle.
Standard valve face angle:
44.5°
If the valve face is worn, replace the valve.

(d) Check the valve head margin thickness.
Standard margin thickness:
1.0 mm (0.0394 in.)
Minimum margin thickness:
0.5 mm (0.0197 in.)
If the margin thickness is less than the minimum, replace the valve.

(e) Check the valve overall length.
Standard overall length:
95.05 mm (3.74 in.)
Minimum overall length:
94.55 mm (3.72 in.)
If the overall length is less than the minimum, replace the valve.

(f) Check the surface of the valve stem tip for wear.
If the valve stem tip is worn, resurface the tip with a grinder or replace the valve.

NOTE: Be careful not to grind off more than the minimum length.

4. INSPECT EXHAUST VALVE
(a) Clean the valves.

(1) Using a gasket scraper, chip off any carbon from the valve head.
(2) Using a wire brush, thoroughly clean the valve.

(b) Using a micrometer, measure the diameter of the valve stem.
Standard valve stem diameter:
5.465 to 5.480 mm (0.215 to 0.216 in.)
(c) Check the valve face angle.

(e) Check the valve overall length.
Standard overall length:
95.10 mm (3.744 in.)
Minimum overall length:
94.60 mm (3.724 in.)
If the overall length is less than the minimum, replace the valve.

(a) Using a caliper gauge, measure the inside diameter of the guide bush.
Standard bush inside diameter:
5.510 to 5.530 mm (0.217 to 0.218 in.)
(b) Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.
Standard oil clearance:
0.025 to 0.060 mm (0.000984 to 0.00236 in.)
Maximum oil clearance:
0.08 mm (0.00314 in.)
If the oil clearance is greater than the maximum, replace the valve and guide bush.
6. INSPECT EXHAUST VALVE GUIDE BUSH

(a) Using a caliper gauge, measure the inside diameter of the guide bush.
Standard bush inside diameter:
5.510 to 5.530 mm (0.217 to 0.218 in.)
(b) Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.
Standard oil clearance:
0.030 to 0.065 mm (0.00118 to 0.00256 in.)
Maximum oil clearance:
0.10 mm (0.00394 in.)
If the oil clearance is greater than the maximum, replace the valve and guide bush.
7. INSPECT INTAKE VALVE SEAT

(a) Apply a light coat of Prussian blue to the valve face.
(b) Lightly press the valve against the seat.

HINT: Do not rotate the valve while pressing it.

(c) Check the valve face and seat.
(1) Check that the contact surfaces of the valve seat and valve face are in the middle area of their respective surfaces, with the width between 1.0 to 1.4 mm (0.0394 to 0.0551 in.).
If not, correct the valve seat.
(2) Check that the contact surfaces of the valve seat and valve face are even around the entire valve seat.
If not, correct the valve seat.
8. INSPECT EXHAUST VALVE SEAT

(a) Using steel squares, measure the deviation of the spring.
Maximum deviation:
2.0 mm (0.0787 in.)
If the deviation is greater than the maximum, replace the valve spring.

(b) Using a vernier caliper, measure the free length of the spring.
Standard free length:
51.29 mm (2.02 in.)
If the free length is not as specified, replace the valve spring.

(c) Using a spring tester, measure the tension of the valve spring when it is compressed to the specified installation length.
Standard installed tension:
210 to 226 N (21 to 23 kgf, 47.2 to 50.7 lbf) at 33.4 mm (1.31 in.)
If the installed tension is not as specified, replace the valve spring.
10. INSPECT VALVE LIFTER

(a) Using a micrometer, measure the lifter diameter at a position 12.3 to 12.7 mm (0.484 to 0.500 in.) from the top surface.
Standard lifter diameter:
30.968 to 30.976 mm (1.2192 to 1.2195 in.)

(b) Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Standard lifter bore diameter:
31.000 to 31.016 mm (1.220 to 1.221 in.)
(c) Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance:
0.024 to 0.050 mm (0.000945 to 0.00196 in.)
Maximum oil clearance:
0.07 mm (0.00276 in.)
If the oil clearance is greater than the maximum, replace the lifter. If necessary, replace the cylinder head.
11. INSPECT CAMSHAFT THRUST CLEARANCE

(a) Inspect the clearance on the intake side.
(1) Install the camshaft.
(2) Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance:
0 to 0.040 mm (0 to 0.00157 in.)
Maximum thrust clearance:
0.12 mm (0.00472 in.)
If the thrust clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
(3) Remove the camshaft.

(b) Inspect the clearance on the exhaust side.
(1) Install the camshaft.
(2) Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance:
0.030 to 0.070 mm (0.00118 to 0.00276 in.)
Maximum thrust clearance:
0.10 mm (0.00394 in.)
If the thrust clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
(3) Remove the camshaft.
12. INSPECT CAMSHAFT GEAR BACKLASH

(a) for Bank 1:
(1) Install the No. 3 camshaft and No. 4 camshaft without installing the camshaft sub-gear and front bearing cap.
(2) Using a dial indicator, measure the backlash.
Standard backlash:
0.020 to 0.200 mm (0.000787 to 0.00787 in.)
Maximum backlash:
0.30 mm (0.0118 in.)
If the backlash is greater than the maximum, replace the drive gear and No. 4 camshaft.
(3) Remove the No. 3 camshaft and No. 4 camshaft.
(4) Remove the camshaft timing tube from the No. 3 camshaft.
(5) Remove the drive gear from the camshaft timing tube.

(b) for Bank 2:
(1) Install the No. 1 camshaft and No. 2 camshaft without installing the camshaft sub-gear and front bearing cap.
(2) Using a dial indicator, measure the backlash.
Standard backlash:
0.020 to 0.200 mm (0.000787 to 0.00787 in.)
Maximum backlash:
0.30 mm (0.0118 in.)
If the backlash is greater than the maximum, replace the drive gear and No. 2 camshaft.
(3) Remove the No. 1 camshaft and No. 2 camshaft.
(4) Remove the camshaft timing tube from the camshaft.
(5) Remove the drive gear from the camshaft timing tube.