Valve Spring: Testing and Inspection

Fig. 11

The valve springs should be tested whenever removed for inspection, reconditioning, or replacement (Fig. 11). The valves have two springs, an inner and an outer. Before testing, the two springs should be separated.

CAUTION: Identity the valve springs because they are to be used in matched pairs only. When replacement is necessary, replace springs as a pair. Do not replace only the inner or the outer springs.

(1) Obtain specifications for spring tension at specified spring length. Refer to Engine Specifications.
(2) Turn table of Special Tool C-647 until the surface is in line with the spring length specification mark on the threaded stud and the zero mark is on the front.
(3) Place inner spring over stud on the table and lift compressing lever to set tone device.
(4) Pull on torque wrench (beam or dial type) 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.
(5) Compare reading to the specification. Discard the springs that do not meet specifications.
(6) Readjust table to specified length for testing the outer spring. Repeat previous steps.