Valve Spring: Service and Repair
VALVE SPRINGSThe valve springs are common for intake and exhaust valves. See Valve Spring Specification chart.
Valve Spring Specification Chart
Testing Valve Springs
Fig. 20
Whenever valves have been removed for inspection, reconditioning or replacement, valve springs should be tested (Fig. 20). As an example: the compression length of the spring to be tested is 38.00 mm (1.496 inch). Turn table of Tool C-647 until surface is in line with the 38.00 mm (1.496 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. Replace any springs that do not meet specifications.
Valve Installation
1. Coat valve stems with clean engine oil and insert them in cylinder head.
2. If valves or seats have been reground, check valve tip height (A) (Fig. 21). If valve tip height for intake valve is greater than 47.59 (1.8737 inch) or 49.14 (1.9347 inch) for exhaust valve, grind valve tip until within specifications. Make sure measurement is taken from cylinder head surface to the top of valve stem.
Fig. 22
3. Install valve seal/spring seat assembly over valve guides on all valve stems (Fig. 22). Ensure that the garter spring is intact around the top of the rubber seal. Install valve springs, valve retainers.
Fig. 21
4. Compress valve springs with a valve spring compressor install locks and release tool. If valves and/or seats are reground, measure the installed height of springs (B) (Fig. 21), make sure measurements are taken from top of spring seat to the bottom surface of spring retainer. If height is greater than 38.75 mm (1.5256 inch), install a 0.762 mm (0.030 inch) spacer in head counterbore under the valve spring seat to bring spring height back within specification.