Valve: Testing and Inspection
VALVESVALVE MECHANISM
1. Inspect each valve for following:
a. Damaged or bent valve stem
b. Rough or damaged face
c. Damaged or unevenly worn stem tip
2. Resurface or replace valve as needed.
Margin thickness
Intake: 0.0394 inch (1.0 mm)
Exhaust: 0.0394 inch (1.0 mm)
3. Measure length of each valve.
Length
Intake: 3.7815 inch (96.05 mm)
Exhaust: 3.7402 inch (95.00 mm)
4. Measure diameter of each valve stem.
Diameter
Intake: 0.2152 - 0.2157 inch (5.465 - 5.480 mm)
Exhaust: 0.2138 - 0.2146 inch (5.430 - 5.450 mm)
5. Measure inside diameter of each valve guide at points shown in figure.
Diameter intake and exhaust valve guide: 0.2165 - 0.2171 inch (5.500 - 5.515 mm)
6. Calculate valve stem-to-valve guide clearance. Subtract outer diameter of valve stem from inside diameter of respective valve guide.
Clearance
Intake valve: 0.0008 - 0.0020 inch (0.020 - 0.050 mm)
Exhaust valve: 0.0020 - 0.0033 inch (0.050 - 0.085 mm)
Max: 0.008 inch (0.20 mm)
7. If clearance exceeds specification, replace valve, and/or valve guide.
8. Measure protrusion height of each valve guide. Replace valve guide as needed.
Intake: 0.5039 - 0.5276 inch (12.8 - 13.4 mm)
Exhaust: 0.5039 - 0.5276 inch (12.8 - 13.4 mm)
NOTE: Intake and exhaust valve guides are different. Be sure to use correct valve guide.
VALVE SEAT
1. Inspect contact surface of each valve seat and valve face for following:
a. Roughness
b. Damage
c. Pitting
d. Cracks
2. Resurface valve seats with a 45° valve seat cutter. Resurface valve faces as needed.
3. Apply a coat of Dychem blue to valve face and valve seat and allow to dry.
4. Inspect valve seating by pressing valve against seat and rotating valve 360°.
a. If Dychem blue is not removed 360° around valve face, replace valve.
b. If Dychem blue is not removed 360° around valve seat, resurface valve seat.
5. Measure seat contact width.
Width: 0.0382 - 0.0618 inch (0.97 - 1.57 mm)
6. Complete seat-cutting process by lapping valve to seat using valve-lapping compound.
NOTE: Clean valves thoroughly before reassembly and insure that all traces of lapping compound has been removed.
VALVE SPRING
1. Inspect each valve spring for cracks and damage.
2. Measure free length and out-of-square. Replace valve springs as needed.
Free length:
Standard: 1.5354 inch (39.0 mm)
Limit: 1.5276 inch (38.8 mm)
Out-of-square: 0.0402 inch (1.02 mm)