In Vehicle Service
VALVE SPRINGS & SEALSREMOVAL - CYLINDER HEAD ON
1. Remove the cylinder head cover.
2. Remove rocker arm shafts assemblies.
3. Rotate crankshaft until piston is at TDC on compression stroke.
4. With air hose attached to adapter tool installed in spark plug hole, apply 90 - 120 psi air pressure.
5. Using Special Tool MD-998772A with adapter 6779 (Fig. 37)compress valve springs and remove valve locks.
6. Remove the valve spring.
7. Remove the valve stem seal.
INSPECTION
When valves have been removed for inspection, reconditioning or replacement, valve springs should be tested (Fig. 38). 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 inches.) 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 Engine Specifications to obtain specified height and allowable tensions. Replace springs that do not meet specifications.
INSTALLATION - CYLINDER HEAD ON
1. Install valve stem seal assembly.
NOTE: On the high output R/T engine, the valve spring MUST be oriented properly when installed. The closely spaced spring coils should be positioned toward the cylinder head (spring seat) (Fig. 41).
2. Position valve spring and retainer on spring seat (Fig. 40) or (Fig. 41).
3. With air pressure applied in cylinder and piston at TDC, use Special Tool MD-998772A to compress valve springs, only enough to install the locks. Correct alignment of tool is necessary to avoid nicking valve stems.
4. Install the rocker arm shaft assemblies.
5. Install the cylinder head cover.