GMC 5232720 Lifter,Valve

Hydraulic lash adjusters are generally reliable and do not need frequent adjustments. A noisy adjuster can be diagnosed while the engine is idling by placing a hose or tubing near each intake and exhaust valve and listening at the other end, or by removing the rocker cover and feeling for shock at the valve spring retainers. If adjustment is correct, noise is often caused by dirt trapped between the plunger and adjuster body. To remove the adjusters, take off the intake manifold and pushrod cover, then remove the valve cover and lift each pushrod out. A special tool can be used to pull the adjusters from their bores, or a sharp scribe can be employed to push them upwards, avoiding pliers on the adjuster body. A stuck adjuster may be freed with carburetor cleaner. Keep adjusters separated and identified for reinstallation. After cleaning each adjuster, inspect for any damage, as nicks or scratches warrant replacement. Check the bottom of the adjuster for wear; a concave condition indicates it should be replaced. When installing adjusters, ensure they are coated with "Molykote" or a similar product, and if original adjusters are reused, they must go back into their original bores. Finally, reinstall the valve components, valve cover, and intake manifold.

Hydraulic lash adjusters are generally reliable and do not need frequent adjustments. To trace a noisy lash adjuster, listen for sounds while idling the engine, using a hose or tubing near each intake and exhaust valve, or by placing a finger on each valve spring retainer to feel for shocks if an adjuster is faulty. A common cause of noise, assuming adjustments are correct, is dirt trapped between the plunger and adjuster body. To remove the adjusters, first take off the intake manifold and pushrod cover if applicable, then remove the valve cover and lift each pushrod out. A special tool can be used to pull the adjusters from their bores, avoiding pliers on the adjuster body, and a stuck adjuster may be freed with carburetor cleaner. Keep all adjusters separated and identified for reinstallation. After cleaning each adjuster, inspect for nicks or damage, particularly at the bottom where it contacts the camshaft; any damage warrants replacement. When reinstalling, ensure adjusters are coated with 'Molykote' or a similar product, and if original adjusters are reused, they must go back into their original bores. Install the valve components, valve cover, and intake manifold with new gaskets, then reassemble the remaining engine components. Fill the radiator with coolant, start the engine to check for leaks, and adjust ignition timing and valves as necessary, rechecking the coolant level after the engine reaches operating temperature.

Before removing the camshaft, test the lobe lift to verify how much wear has occurred on the cam lobes. First, set number one piston at TDC on compression stroke. Then loosen rocker arm nuts and pivot the arms sideways. Thereafter fit a dial indicator over the engine, and set its stem touching top of first pushrod. Zero 0 Dial Indicator as well as slowly rotate crankshaft in normal direction until needle of indicator stops and begins to move in opposite way. Record this reading then replicate for every other valve. Where the maximum value of cam lobe lift is below that specified, install a new camshaft. Take off the intake manifold, rocker arms, push rods, timing chain and cam sprocket from the head prior to removing it from cylinder block; unfasten balancer shaft drive and driven gears if any; draw out camshaft very cautiously holding it at near block area; after removal look up bearing journals if they were worn out or damaged; inspect with micrometer bearing surfaces for increased clearances or ovality conditions; also review cams for discoloration as well as scoring marks being present; wash out lash adjusters and verify them under light projections or even examining several pittings or variable wear patterns; take off old gear roller followers too when replacing lobes including wipers along with it only; check rollers on roller type Lash Adjusters for wear/scoring/any damage that might be noticed therefrom/moly based grease/lube oil between lobes besides journals/insert nozzle into a hole (where not abraded), which must be careful at all costs not to scrape groove bearings. Next Lubricate all journals both lateral zones plus lopes with molly base greases or assembly compounds intended strictly for engines respectively: insert executive's element without scratching related beds but before enjoying harmonic aspect together by looking whether matching bones actually are still available plus need refitting them again: finally, oil changes should chiefly concern replacement of filters too then engine run on.

A noisy hydraulically operated intake valve lash adjuster may be masked when the engine is stationary by positioning a length of hose or tubing against the approximate position of each lash adjuster and listening at the other end of the tube. If adjustment is to be believed, then, the most probable root of a noisy valve lash adjuster is the wear at the adjuster foot and camshaft lobe or deterioration or grime of the parts inside. Start with the rocker arm covers then proceed to take off the intake manifold. Turn the rocker arm clockwise until it is loose from the pushrod; remove this pushrod also and make sure that if more than one are removed they are set in an order so as to be replaced where they are required. If it is necessary to remove the lash adjuster, there is a specific lash adjuster removal tool; it is dangerous to use pliers or other tools on the outside of the adjuster body. If the lash adjusters are to be used again, it may be inevitable to organize them in a proper way for reusing them. Clean and dry the lash adjusters then look for wear through gauge rod and piston rod, look for flat spots. Lash adjusters become worn and need to be changed to the new ones; thus, the camshaft has to be replaced also. If the lash adjusters are in good shape, then they can be reused in the original position; it must be noted that the lash adjusters must always be coated with moly-based grease, or engine assembly lube. The steps that are followed in the actual installation of a device are as follows: The remaining steps are simply the reverse of the above removal steps.

Install the balancer shaft drive gear, ensuring proper alignment of timing marks. Install the timing chain and sprockets, lubricate the lifters with clean engine oil, and reinstall them in their original locations if applicable.

Clean the lifters with solvent and check for wear. If the base is concave or damaged, replace the entire set.

To determine cam lobe wear, you should first position the number one piston at TDC on the compression stroke. Then, loosen the rocker arm nuts and pivot the rocker arms sideways. Afterward, mount a dial indicator on the engine and position the plunger against the top of the first pushrod. Zero the dial indicator and slowly turn the crankshaft in the normal direction of rotation until the indicator needle stops and begins to move in the opposite direction. Record this figure and repeat the check for each valve.

Measure the inside diameter of each camshaft bearing and record the results, taking two measurements at each bearing.

The remaining installation steps follow the reverse order of removal.

For 1987 and later models, the VS engine is equipped with roller type hydraulic valve lifters, which use lifter retainers and guides to prevent rotation on the camshaft lobes.