Cylinder Head Assembly: Testing and Inspection

INSPECTION

CYLINDER HEAD

1. Inspect for flatness.
Using a precision straight edge and feeler gauge, measure the surface contacting the cylinder block and the manifolds for warpage.





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 valve stems and valve guides.
1) Using a caliper gauge, measure the inside diameter of the valve guide.





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





3) Subtract the valve stem diameter measurement from the valve guide inside diameter measurement.

Valve stem-to-guide clearance
[Standard]
Intake: 0.020-0.047 mm (0.0008-0.0018 in.)
Exhaust: 0.030-0.054 mm (0.0012-0.0021 in.)
[Limit]
Intake: 0.07 mm (0.0027 in.)
Exhaust: 0.09 mm (0.0035 in.)

2. Inspect valves.
1) Check the valve is ground to the correct valve face angle.
2) Check that the surface of the valve for wear. If the valve face is worn, replace the valve.
3) Check the valve head margin thickness. If the margin thickness is less than minimum, replace the valve.





4) Check the valve length.

Length
Intake: 105.27 mm (4.1445in)
Exhaust: 105.50 mm (4.1535in)

5) Check the surface of the valve stem tip for wear. If the valve stem tip is worn, replace the valve.
3. Inspect valve seats
Check the valve seat for evidence of overheating and improper contact with the valve face.
If the valve seat is worn, replace cylinder head.
Before reconditioning the seat, check the valve guide for wear. If the valve guide is worn, replace cylinder head. 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 valve springs.
1) Using a steel square, measure the out-of-square of the valve spring.
2) Using vernier calipers, measure the free length of the valve spring.





MLA

1. Inspect MLA.
Using a micrometer, measure the MLA outside diameter.

MLA O.D.
Intake/Exhaust: 34.964-34.980 mm (1.3765 1.3771 in.)

2. Using a caliper gauge, measure MLA tappet bore inner diameter of cylinder head.

Tappet bore I.D.
Intake/Exhaust: 35.000-35.025 mm (1.3779 1.3789 in.)

3. Subtract MLA outside diameter measurement from tappet bore inside diameter measurement.

MLA to tappet bore clearance
[Standard]
Intake/Exhaust 0.020-0.061 mm (0.0008 0.0024 in.)
[Limit]
Intake/Exhaust 0.07 mm (0.0027 in.)

CAMSHAFT

1. Inspect cam lobes.
Using a micrometer, measure the cam lobe height.





If the cam lobe height is less than standard, replace the camshaft.
2. Inspect camshaft journal clearance.
1) Clean the bearing caps and camshaft journals.
2) Place the camshafts on the cylinder head.
3) Lay a strip of plastigage across each of the camshaft journals.





4) Install the bearing caps.

CAUTION: Do not turn the camshaft.

5) Remove the bearing caps.
6) Measure the plastigage at its widest point.





If the oil clearance is greater than maximum, replace the camshaft. If necessary, replace cylinder head.
7) Completely remove the plastigage.
8) Remove the camshafts.
3. Inspect camshaft end play.
1) Install the camshafts.
2) Using a dial indicator, measure the end play while moving the camshaft back and forth.





If the end play is greater than maximum, replace the camshaft. If necessary, replace cylinder head.
3) Remove the camshafts.

CVVT ASSEMBLY

1. Inspect CVVT assembly.
1) Check that the CVVT assembly will not turn.
2) Apply vinyl tape to the retard hole except the one indicated by the arrow in the illustration.





3) Wind tape around the tip of the air gun and apply air of approximately 150kpa(l.5 kgf/cm2, 21 psi) to the port of the camshaft.
(Perform this in order to release the lock pin for the maximum delay angle locking.)

NOTE: When the oil splashes, wipe it off with a shop rag.

4) Under the condition of (3), turn the CVVT assembly to the advance angle side (the arrow marked direction in the illustration) with your hand.
Depending on the air pressure, the CVVT assembly will turn to the advance side without applying force by hand. Also, under the condition that the pressure can be hardly applied because of the air leakage from the port, there may be the case that the lock pin could be hardly released.





5) 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 22.5°

6) Turn the CVVT assembly with your hand and lock it at the maximum delay angle position (counter clockwise).