Buick 12721201 LIFTER ASM-VLV

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Special tools are necessary for this procedure. Begin by disconnecting the negative battery cable and removing the timing chain and sprockets. Next, remove the timing chain housing-to-camshaft housing bolts, the ignition coil and module assembly, and disconnect the Idle speed power steering pressure switch. Remove the power steering pump and brackets, followed by the power steering pump drive pulley. Remove the oil/air separator as an assembly with the hoses attached, and then remove the fuel rail from the cylinder head. For the exhaust (rear) part, unplug the oil pressure sending unit wire and unbolt the engine lifting bracket. For both the intake and exhaust, loosen the camshaft housing-to-cylinder head bolts in 1/4-turn increments, following the tightening sequence in reverse. Lift the housing off the cylinder head and remove the camshaft cover and housing bolts. Carefully lift the camshaft out of the housing. Remove old gasket material and clean surfaces. Remove the oil seal from the intake camshaft. Remove the lash adjusters and store them in order. Visually inspect the lash adjusters and measure bore and lash adjuster diameters. When installing, position the camshaft housing with a new gasket, coat components with oil, install lash adjusters, and lubricate the lip of the oil seal on the intake camshaft. Install the camshaft in the housing with the sprocket dowel pin UP. Apply pipe sealant to bolt threads, install new housing seals, and install the camshaft cover and bolts, ensuring the oil seal depth is 0.020 inches from the outer housing face. Tighten the bolts in the specified sequence. Reinstall the power steering pump pulley, remaining parts in reverse order, and change the oil and filter. If new lash adjusters are installed or lash adjuster noise occurs, follow a purging procedure involving warming up the engine and increasing engine speed to eliminate the noise. Finally, road test the vehicle and check for leaks.

To diagnose a noisy Lash Adjuster, you can employ a few methods. Firstly, while the engine is idling, you can use a mechanic's stethoscope or a length of hose to pinpoint the noisy Lash Adjuster by listening at the other end near the valve locations. Another approach involves removing the rocker arm cover and, with the engine idling, touching each valve spring retainer one at a time. If a Lash Adjuster is faulty, you will feel a noticeable shock at the retainer each time the valve seats. Common causes of noisy Lash Adjusters include dirt trapped inside the Lash Adjuster and issues related to oil flow, viscosity, or pressure. Before concluding that the Lash Adjusters are problematic, it's essential to inspect the engine oil for fuel contamination, ensure it's at the correct level, clean, and has the appropriate viscosity. For the removal process, begin by removing the intake manifold and rocker arm cover(s). Then proceed to remove the rocker arms and pushrods. If your engine utilizes roller Lash Adjusters (1994 and newer models), also remove the lifter guide. There are various methods to extract the Lash Adjusters from the bores. While a special tool designed for this purpose is available, it may not be necessary in all cases. In newer engines without significant varnish buildup, Lash Adjusters can often be removed using a small magnet or even your fingers. A machinist's scribe with a bent end can also be employed to pull the Lash Adjusters out by positioning the point under the retainer ring in the top of each Lash Adjuster. It's crucial to avoid using pliers for Lash Adjuster removal unless you intend to replace them, as pliers may damage the precision machined and hardened Lash Adjusters. Before removing the Lash Adjusters, ensure they are carefully stored in a well-labeled container to guarantee they are reinstalled in their original positions. Note that some engines may have both standard and 0.010-inch oversize Lash Adjusters installed at the factory, distinguishable by a drop of white paint and a 0.25 (mm) OS stamp on them. Regarding inspection and installation, it's important to note that Lash Adjuster parts are not sold separately. If the Lash Adjusters are worn, they should be replaced with new ones, and if your engine features conventional Lash Adjusters, the camshaft must be replaced as well. It's crucial never to mix used conventional Lash Adjusters with a new camshaft or new conventional Lash Adjusters with a used camshaft. However, used roller Lash Adjusters can be reinstalled with a new camshaft, and the original camshaft can be used if new roller Lash Adjusters are installed, provided that the used parts are in good condition. When reinstalling used Lash Adjusters, make sure they are returned to their original bores, soak new Lash Adjusters in oil to remove trapped air, and coat all Lash Adjusters with moly-base grease or engine assembly lube before installation. The remaining installation steps should be carried out in reverse order, and for those installing roller Lash Adjusters, ensure the lifter guide bolts are properly tightened. Finally, run the engine and inspect for any oil leaks.

When installing new lifters:A new camshaft is required when installing new lifters; never use used lifters unless they can be placed back in their original locations with the original camshaft.Ensure the lifters are coated with moly-base grease or engine assembly lube during installation.Proceed with the remaining steps in reverse order to complete the lifter replacement process.

To determine the extent of cam lobe wear, position the number one piston at TDC on the compression stroke, remove the valve cover, and loosen the rocker arm nuts to access the pushrods. Then, mount a dial indicator on the engine, position the plunger against the top of the first pushrod, and zero the dial indicator. Slowly turn the crankshaft in the normal direction of rotation until the indicator needle stops and moves in the opposite direction, indicating maximum cam lobe lift. Record this figure and repeat the check for each valve.

For installation, the camshaft bearing journals and cam lobes should be lubricated with camshaft and lifter assembly lube.

If the lobes are in good condition and the measurements are as specified, the camshaft can be reused.

Proper labeling and storage of the lifters are essential to ensure that they are returned to their original locations during reinstallation, preventing any mix-up.