Cylinder Head On

REMOVAL - CYLINDER HEAD ON
1) Disconnect negative battery cable.
2) Remove upper intake manifold.
3) Remove cylinder head cover(s).
4) Remove rocker arm and shaft assembly.
5) Remove spark plugs.
6) Rotate the crankshaft clockwise, until the number 1 piston is at TDC (Top Dead Center) on the compression stroke.
7) With air hose attached to spark plug adapter installed in number 1 spark plug hole, apply 620.5 to 689 kPa (90 to 100 psi) air pressure. This is to hold valves into place while servicing components.

NOTE: It may be necessary to use accessory studs 6886, adaptor arm 6887 and 6885 valve adaptor along with MD 998772A, to compress the valve spring on the right cylinder head exhaust valves.






8) Using Tool MD 998772A (1) with adapter 6527 (4) or equivalent, compress valve spring and remove valve locks (5). Release tension on valve spring, remove retainer (5) and valve spring (Fig. 68).
9) Remove valve stem seal, if required.
10) Follow the same procedure on the remaining 5 cylinders using the firing sequence 1-2-3-4-5-6. Make sure piston is at TDC in each cylinder of the valve spring that is being removed.
11) Remove spark plug adapter tool.

INSPECTION





When valves have been removed for inspection, reconditioning or replacement, valve springs should be tested (Fig. 69). 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 new valve seal(s) if required.
2) Place valve spring (color-coded end facing up) and valve retainer into position.





3) Compress valve spring using Special Tool MD 998772A (1) with Adapter 6527 (4) only enough to install locks (2) (Fig. 72).
4) After installing locks, release tension on valve spring and verify proper installation.
5) Remove Special Tool MD 998772A (1) and spark plug adapter tool.
6) Install rocker arm and shaft assembly.
7) Install cylinder head cover(s).
8) Install spark plugs.
9) Install upper intake manifold.
10) Connect negative battery cable.