Service Procedures
CYLINDER HEAD COMPONENTS - IN VEHICLE SERVICEROCKER ARMS AND PUSH RODS
REMOVAL
1. Disconnect spark plug wires by pulling on the boot straight out in line with plug.
2. Remove cylinder head cover and gasket.
Rocker Arms:
3. Remove the rocker arm bolts and pivots. Place them on a bench in the same order as removed.
4. Remove the push rods and place them on a bench in the same order as removed.
INSTALLATION
1. Rotate the crankshaft until the V6 mark lines up with the TDC mark on the timing chain case cover. This mark is located 147° ATDC from the No. 1 firing position.
CAUTION: DO NOT rotate or crank the engine during or immediately after rocker arm installation. Allow the hydraulic roller tappets adequate time to bleed down (about 5 minutes).
2. Install the push rods in the same order as removed.
3. Install rocker arm and pivot assemblies in the same order as removed. Tighten the rocker arm bolts to 28 Nm (21 ft. lbs.) torque.
4. Install cylinder head cover.
5. Connect spark plug wires.
VALVE STEM SHIELDS AND SPRINGS
REMOVAL
1. Set engine basic timing to Top Dead Center (TDC).
2. Remove the air cleaner.
3. Remove cylinder head covers and spark plugs.
4. Remove coil wire from distributor and secure to good ground to prevent engine from starting.
5. Using suitable socket and flex handle at crankshaft retaining bolt, turn engine so the No. 1 piston is at TDC on the compression stroke.
6. Remove rocker arms.
7. With air hose attached to an adapter installed in No.1 spark plug hole, apply 620 - 689 kPa (90 - 100 psi) air pressure.
8. Using Valve Spring Compressor Tool MD-998772A and adapter 6716A, compress valve spring and remove retainer valve locks and valve spring.
INSTALLATION
1. Install seals on the exhaust valve stem and position down against valve guides.
2. The intake valve stem seals should be pushed firmly and squarely over the valve guide using the valve stem as a guide. DO NOT force seal against top of guide. When installing the valve retainer locks, compress the spring only enough to install the locks.
3. Follow the same procedure on the remaining 5 cylinders using the firing sequence 1-6-5-4-3-2. Make sure piston in cylinder is at TDC on the valve spring that is being removed.
4. Remove adapter from the No.1 spark plug hole.
5. Install rocker arms.
6. Install covers and coil wire to distributor.
7. Install air cleaner.
8. Road test vehicle.
Testing Valve Spring For Compressed Length:
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 1-5/16 inch Turn table of Universal Valve Spring Tester Tool until surface is in line with the 1-5/16 inch mark on the threaded stud. Be sure the zero mark is to 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 2. 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.