Valve Inspection
VALVE INSPECTIONValve Inspection
1. Inspect the following valve areas:
^ the (A) end of the stem for grooves or scoring.
^ the (B) valve face for pits, grooves or scores.
^ the (C) valve head for signs of burning, erosion, warpage and cracking. Minor pits, grooves and other abrasions may be removed.
^ the (D) valve face angle for wear.
Valve Stem Diameter
1. Measure the diameter of each intake valve stem at the points shown. Verify the diameter is within specification.
Intake (STD.) 7.960 - 7.940 mm (0.3134 - 0.3126 inch)
Exhaust (STD.) 7.948 - 7.928 mm (0.3129 - 0.3121 inch)
2. Measure the diameter of each exhaust valve stem at the points shown. Verify the diameter is within specification.
Valve Stem Oil Clearance
1. Install the Valve Stem Clearance Tool SST 303-004 (TOOL-6505-E) or equivalent on the valve stem and install Dial Indicator With Bracketry. Lower the valve until the Valve Stem Clearance Tool SST 303-004 (TOOL-6505-E) or equivalent contacts the upper surface of the valve guide.
Note: The valve stem diameter must be within specification before checking valve stem-to-valve guide clearance.
2. Move the Valve Stem Clearance Tool toward the Dial Indicator and zero the Dial Indicator. Move the Valve Stem Clearance Tool away from the Dial Indicator and note the reading. The reading will be double the valve stem-to-valve guide clearance. Valves with oversize stems will need to be installed if out of specification.
Valve Clearance Inspection
1. Position SST T71P-6513-B or equivalent on the rocker arm.
Note:
^ Valve stem-to-valve rocker arm clearance should be within specification with the hydraulic valve tappet completely collapsed. Repeated valve reconditioning operations (valve and/or valve seat refacing) will decrease the clearance to the point that if it is not compensated for, the hydraulic valve tappet will cease to function and the valve will be held open.
^ The positive stop rocker arm bolts eliminate the necessity to adjust the valve clearance. However, to obtain the specified valve clearance, it is important that all valve components be in a serviceable condition and installed and tightened properly.
^ To determine whether a shorter or a longer push rod is necessary, make the following check.
2. Slowly apply pressure to bleed down the valve tappet until the plunger is completely bottomed. Hold the valve tappet in this position and check the available clearance between the rocker arm and the valve stem tip with a feeler gauge.
3. If the clearance is less than specification, install a shorter push rod. If the clearance is greater than specification, install a longer push rod.
4. With No. 1 piston on TDC at the end of compression stroke check the following valves:
^ No. 1 exhaust valve No. I intake valve
^ No. 3 exhaust valve No. 2 intake valve
^ No. 6 exhaust valve No. 4 intake valve
5. Rotate crankshaft 360 degrees to position No. 2 and check the following valves:
^ No. 2 exhaust valve No. 3 intake valve
^ No. 4 exhaust valve No. 5 intake valve
^ No. 5 exhaust valve No. 6 intake valve