Rocker Arms and Camshaft
ROCKER ARMS AND CAMSHAFT
REMOVAL AND INSTALLATION
Required Special Tools:
^ MB991559: Camshaft Oil Seal Installer Adaptor
^ MD998442: Air Bleed Wire
^ MD998443: Lash Adjuster Holder
^ MD998713: Camshaft Oil Seal Installer
REMOVAL SERVICE POINT
<> ROCKER ARMS AND SHAFT REMOVAL
CAUTION: If the lash adjuster is re-used, clean the lash adjuster.
Set special tool MD998443 to prevent the lash adjuster coming free and falling to the floor.
INSTALLATION SERVICE POINTS
>>A<< CAMSHAFT INSTALLATION
1. Apply engine oil to the camshaft journals and cams.
2. The camshaft for the right bank has a slit for driving the distributor at the rear end. The camshaft for the left bank has no slit. Be careful to install the correct camshaft in the correct position.
>>B<< LASH ADJUSTER INSTALLATION
CAUTION: If the lash adjuster is re-used, clean the lash adjuster.
1. Fit the lash adjuster onto the rocker arm without allowing diesel fuel to spill out. Fit special tool MD998443 to prevent the lash adjuster coming free and falling to the floor.
>>C<< ROCKER ARM, ROCKER ARM SHAFT AND ROCKER SHAFT SPRING INSTALLATION
1. Rotate the camshaft until the dowel pin on its front end is located as shown in the illustration.
NOTE: Placing the camshaft in the illustrated position minimizes the amount of cam lift, making it easier to install the rocker arm and shaft assemblies.
2. Install the exhaust side rocker arm "C" and shaft assembly to the cylinder head.
3. Install the inlet side rocker arms "A" and "B" and shaft assembly to the cylinder head.
4. Insert the rocker shaft spring to the intake side rocker arm shaft as illustrated.
5. Make sure that the notch in the end of the rocker arm shaft is facing the direction as shown.
>>D<< CAMSHAFT OIL SEAL INSTALLATION
1. Apply engine oil to the lip area of the oil seal and the front end outside diameter of the camshaft.
2. Using special tools MD998713 and MB991559 (for the left bank only), install the camshaft oil seals.
INSPECTION
CAMSHAFT
Measure the cam height. If it is below the limit, replace the camshaft.
Standard value:
Minimum limit:
ROCKER ARM
1. Check the roller surface. If any dents, damage or seizure is evident, replace the rocker arm.
2. Check rotation of the roller. If it does not rotate smoothly or if looseness is evident, replace the rocker arm.
3. Check the inside diameter. If damage or seizure is evident, replace the rocker arm.
LASH ADJUSTERS
CAUTION
^ The lash adjusters are precision-engineered mechanisms. Do not allow them to become contaminated by dirt or other foreign substances.
^ Do not attempt to disassemble the lash adjusters.
^ Use only fresh diesel fuel to clean the lash adjusters.
1. Prepare three containers and approximately 5 dm3 (30.5 quart) of diesel fuel. Into each container, pour enough diesel fuel to completely cover a lash adjuster when it is standing upright. Then, perform the following steps with each lash adjuster.
2. Place the lash adjuster in container A and clean its outside surface.
NOTE: Use a nylon brush if deposits are hard to remove.
CAUTION: The steel ball spring is extremely weak, so the lash adjuster's functionality may be lost if the air bleed wire is pushed in hard.
3. While gently pushing down the internal steel ball using wire [0.5 mm (0.020 in.) in diameter] or special tool MD998442, move the plunger through five to ten strokes until it slides smoothly. In addition to eliminating stiffness in the plunger, this operation will remove dirty oil.
NOTE: If file plunger remains stiff or file mechanism appears otherwise abnormal, replace file lash adjuster.
4. Remove the lash adjuster from the container. Then, push down the steel ball gently and push the plunger to eliminate diesel fuel from the pressure chamber.
CAUTION: The steel ball spring is extremely weak, so the lash adjuster's functionality may be lost if the air bleed wire is pushed in hard.
5. Place the lash adjuster in container Be Then, gently push down the internal steel ball using wire [0.5 mm (0.020 in.) in diameter] or special tool MD998442 and move the plunger through five to ten strokes until it slides smoothly. This operation will clean the lash adjuster's pressure chamber.
6. Remove the lash adjuster from the container. Then, push down the steel ball gently and push the plunger to eliminate diesel fuel from the pressure chamber.
CAUTION: Do not use container C for cleaning. If cleaning is performed in container C, foreign matter could enter the pressure chamber when the chamber is filled with diesel fuel.
7. Place the lash adjuster in container C. Then, gently push down the internal steel ball using wire [0.5 mm (0.020 in.) in diameter] or special tool MD998442.
8. Stand the lash adjuster with its plunger at the top, then push the plunger downward firmly until it moves through its greatest possible stroke. Return the plunger slowly, then release the steel ball and allow the pressure chamber to fill with diesel fuel.
9. Remove the lash adjuster from the container, then stand the lash adjuster with its plunger at the top. Push the plunger firmly and check that it does not move. Also, check that the lash adjuster's height matches that of a new lash adjuster.
NOTE: If the lash adjuster contracts or moves, perform operations (7) through (9) again to fill it with diesel fuel completely. Replace the lash adjuster if it contracts or moves after performing these steps.
10. Stand the lash adjuster upright to prevent diesel fuel from spilling out. Do not allow the lash adjuster to become contaminated by dirt or other foreign matter. Fit the lash adjuster onto the engine as soon as possible.