Before you can take out the valve cover(s) you should turn the rocker arm shaft support bolts, starting from the central one and working outwards, until they can be turned by hand-two turns at a time. Remove the rocker shaft assembly from the cylinder head; it is advisable to place a mark on each shaft so that it can easily be reassembled in position. Take out the pushrods and put each part in its place in a holder such that all its ends will be at the top. Remove the pins in the rocker arm assembly and place the parts in a sequential manner on the work bench so that one does not get mixed up with the other. Each rocker arm must be checked for any signs of wear, crack, or damage on those portions of the centres where it bears upon the pushrods and the valve stem faces and all oil ways must be clear. Inspect the bore of the rocker arm and the corresponding position on the rocker shaft for wear, cracks, and galling of the parts and then replace the parts if they are worn out. As mentioned above closely examine the pushrods for any evidence of cracking or excessive wear roll the rods on a piece of plate glass to check for bending. When necessary the plugs at the two ends of the rocker shafts may be withdrawn by knocking out with the aid of a long steel bar. If plugs have been withdrawn, insert new ones with hammer and suitable drift. Fit the rocker assembly with the new cotter pins in the ends of the rocker shaft where the split is up with the holes facing down as indicated on the front of both rocker shafts by a notch. The end of the pushrods should be lubricated with assembly lube before fitting them into the engine, original pushrods should be refitted. Grease the rocker arm pads and after that fix the rocker arm assembly on the engine with the notch on the front end of the shaft downward. Insert the rocker arm ball ends on the pushrods and fasten the rocker shaft support bolts and turn those to a two turn at a time with the help of torque wrench until they will reach the specified torque in everywhere but in the centre bolt. The remaining of the installation is done in the reverse order as that of the removal.
