INSPECTION


CYLINDER HEAD

1.Check the cylinder head gasket surface for flatness by using a straight edge and feeler gauge.
Standard value: Less than 0.03 mm
Limit: 0.2 mm
2.If it exceeds the limit, correct to meet specification.
Grinding limit: *0.2 mm

    * Includes combined with cylinder block grinding.
Cylinder head height (Specification when new): 120 mm

VALVE

1.Check the valve seat contact. Valve seat contact should be uniform at the center of the valve face. If incorrect, reface using a valve refacer.
2.If the margin is below the limit, replace the valve.
Standard value:
    Intake 1.0 mm
    Exhaust 1.2 mm
Limit:
    Intake 0.5 mm
    Exhaust 0.7 mm

3.Measure the valve’s total length. If the measurement is less than the limit, replace the valve.
Standard value:
    Intake 112.00 mm
    Exhaust 113.81 mm
Limit:
    Intake 111.50 mm
    Exhaust 113.31 mm

VALVE SPRING

1.Measure the free height of the spring. If it is less than the limit, replace.

    Standard value: 51.03 mm
    Limit: 50.03 mm
2.Measure the squareness of the spring. If it exceeds the limit, replace.
Standard value: 2° or less
Limit: 4°

VALVE GUIDE

Measure the clearance between the valve guide and valve stem. If it exceeds the limit, replace the valve guide or valve, or both.
Standard value:
    Intake 0.020 - 0.047 mm
    Exhaust 0.035 - 0.062 mm
Limit:
    Intake 0.10 mm
    Exhaust 0.15 mm

VALVE SEAT

Assemble the valve, then measure the contact width. If the measurement exceeds the specified limit, replace the valve seat.
Standard value: 0.9 - 1.3 mm

VALVE SEAT RECONDITIONING PROCEDURE

1.Before correcting the valve seat, check for clearance between the valve guide and valve and, if necessary, replace the valve guide.
2.Using the seat grinder, correct to obtain the specified seat width and angle.
Standard value: 43.5° - 44°
3.After correcting the valve seat, lap the valve and valve seat using lapping compound. Then, check the valve stem projection.

VALVE SEAT REPLACEMENT PROCEDURE

1.Cut the valve seat from the inside to thin the wall thickness. Then, remove the valve seat.

2.Rebore the valve seat hole in the cylinder head to a selected oversize valve seat diameter.
Intake seat ring hole diameters
    0.3 oversize: 34.300 - 34.325 mm
Exhaust seat ring hole diameters
    0.3 oversize: 31.800 - 31.825 mm
3.When the valve sheet is a press fit, engine oil is applied to the valve sheet or the cylinder head not to damage the inside diameter of the cylinder head.
4.Using a valve seat cutter, correct the valve seat to the specified width and angle.
See "VALVE SEAT RECONDITIONING PROCEDURE" on the previous page.

VALVE GUIDE REPLACEMENT PROCEDURE

1.Using a press, remove the valve guide toward the cylinder block.
2.
caution Do not install a valve guide of the same size again.
Rebore the valve guide hole of the cylinder head so that it fits the press-fitted oversize valve guide.
The valve guide hole diameter of the cylinder head
    0.05 oversize 11.050 - 11.068 mm

3.Press-fit the valve guide until it protrudes 13.7 - 14.3 mm from the cylinder head top surface as shown in the illustration.
note When press-fitting the valve guide, work from the cylinder head top surface.
note Pay attention to the difference in length of the valve guides. (Intake side: 45.5 mm; exhaust side: 50.5 mm)
note After installing the valve guides, insert new valves in them to check for smooth operation.