Valve Spring: Testing and Inspection

1. Whenever valves have been removed for inspection, reconditioning or replacement, valve springs should be tested.
As an example, the compression length of the spring to be tested is 33.34 mm (1.313 inch). Turn the table of spring compressor tool until surface is in line with the 33.34 mm (1.313 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. 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. Refer to specifications to obtain specified height and allowable tensions. Discard the springs that do not meet specifications.
Free length 46 mm (1.811 inch).
Spring tension with the valve closed is 246 - 270 N 138.0 mm (50 - 60 Lbs./1.496 inch) and with the valve open is 459 - 611 N/29.3 mm (123 - 137 lbs./1.153 inch).
2. Inspect each valve spring for squareness with a steel square and surface plate, test springs from both ends. If the spring is more than 1.5 mm (0.06 inch) out of square, install a new spring.