Ford YL2Z-6564-AA Valve Rocker Arm Assembly

We find two ways of removing the rocker arms and lash adjusters in this model engine. The manufacturer describe a technique, by which the rocker arms can be withdrawn without having to withdraw the camshaft(s), using a valve spring compressor for SOHC engine. This compressor employs the camshaft as its fulcrum and, with a ratchet or a breaker bar, compresses the valve spring in an attempt to reduce pressure on the rocker arm. The other approach is much more destructive, involving the stripping of the camshaft. This two ways give the same readings but use of the manufacturers special tool is way easier if available. Firstly, take off the valve cover or covers and then have the valve spring compressor placed so that it removes the required pressure to free the rocker arm. All the camshaft rocker arms and hydraulic lash adjusters need to be fitted back in their correct locations, therefore one should take great care and make sure that after disassembly none of the parts get misplaced and as such one should make sure that all the parts get labeled so that during assembly there is no confusion. Then, which is done to reduce the amount of backlash between the valve stem and the bucket take out the hydraulic lash adjuster and Ricardo recommends that it together with the rocker arm must be arranged in an orderly manner to facilitate its replacement. If the vehicle has high mileage, the adjusters may be gummed up and somewhat stubborn, they can be removed with penetrating oil. Check all adjusters for signs of wear or damage because they tend to become clogged as miles are put on the engine and think about new ones if there is doubt the condition of them or if there is noise coming from the valves. Using a thin wire or paper clip it is possible to observe the movement of the plunger to be not more than 1.5mm in total. In the case of any adjustment that requires replacement, it is preferable to replace the whole set so that no further repairs will be required. Also check the rocker arms for wear or damage at the roller area, on the top edge of the stem, and at the lash adjuster contact place. Before fixing the lash adjusters, purge the air from them by placing the adjusters vertically, immersed in the oil and proceed to pull the plunger upwards and downwards to charge the adjuster. Coat the end of the valve stem, the rocker arm, and the hole where the lash adjuster is to go with clean engine oil and then fit the lash adjusters and the rocker arms as the valve spring is compressed. If applied, removal is relatively simple and the installation process is exactly the opposite of removal. When replacing the adjusters, it is advisable that there will be some noise when starting the engine until all the lash adjusters have been purged of any air; while operating the engine, bring it from idle to 3000 rpm, then give it a cool down; on restarting, the noise should be gone.

Before removing the valve cover(s), loosen the Rocker arm shaft support bolts, in a turn of turn basis beginning with the middle bolt in order not to stripped the head by the pull of valve spring when loosening the bolt by hand. Remove the rocker arm shaft assembly from the cylinder head and, then, visually differentiate each shaft assembly so that it could be fitted back into the same place. Then, take out the push rods and put them on a holder making sure you have arranged them in a manner that will allow for easy reinstallation. Remove the pins from the rocker arm assembly and lay the pieces on the workbench that they will not be mixed up. Check each rocker arm to see that it is not worn, cracked, or damaged especially at the ends where it bears on the push rods and valve stems: oil passages should be open. Measure the wear on the rocker arm bore combined with the rocker shaft worn position and replace the defective part. The push rods should be examined for cracks and signs of wear; the entire length of these should be rolled between two flat surfaces in order to identify bending. If this is so, the plugs which can be seen, protruding from the ends of the rocker shafts have to be removed and new ones inserted after the old ones have been knocked out. Rocker assembly can now be assembled and areas that have friction with engine assembly lube and new cotter pins are fastened at the ends of the rocker shaft with the oil hole facing downwards. Before final installation of the push rods, be sure to apply engine assembly lube on both ends of the rods, if the rods are original ones, you must place them back to their original positions. Grease the rocker arm pads and replace the rocker arm along with its positions on the notches on the shafts and the ball ends in the push rods . Torque the rocker shaft support bolts in a turning sequence from the center bolt to the outside in a two turn increments to the required torque and in the same manner that was followed to remove them.

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.

Install the special valve spring compressor and compress the spring just enough to remove the rocker arm.

Install the pushrods.

The first step is to remove the valve cover(s).