Initial Inspection and Diagnostic Overview

VALVE INSPECTION
1. Clean valves thoroughly and discard burned, warped and cracked valves.
2. Measure valve stems for wear. Measure stem about 60 mm beneath the valve lock grooves.
3. If valve stems are worn more than 0.05 mm (0.002 inch), replace valve.

VALVE GUIDES
1. Remove carbon and varnish deposits from inside of valve guides with a reliable guide cleaner.





Fig. 62





Fig. 63

2. Using a small hole gauge and a micrometer, measure valve guides in 3 places top, middle and bottom (Fig. 62). Replace guides if they are not within specification. For specifications.

TESTING VALVE SPRINGS





Fig. 64

1. Whenever valves have been removed for inspection, reconditioning or replacement, valve springs should be tested Special Tool C-647. As an example, the compression length of the spring to be tested is 33.34 mm (1-5/16 inch). Turn tool table until surface is in line with the 33.34 mm (1-5/16 inch) mark on the threaded stud and the zero mark on the front. Place spring over stud on the table and lift compressing lever to set tone device (Fig. 64). Pull on torque wrench until ping is heard. Take reading on torque wrench at this instant. Multiply this reading by two. This will give the spring load at test length. Fractional measurements are indicated on the table for finer adjustments. Discard the springs that do not meet specifications. The following specifications apply to both intake and exhaust valve springs:
- Valve Closed Nominal Tension-70 lbs. 39.8 mm (1.57 inch)
- Valve Closed Nominal Tension-160 lbs. 32.6 mm (1.28 inch)
2. Verify springs are not distorted with a steel square and surface plate, check springs from both ends. If the spring is more than 1.5 mm (1/16 inch) out of square, install a new spring.



CLEANING
Clean all valve guides, valves and valve spring assemblies thoroughly with suitable cleaning solution before reassembling.