Chevrolet 17120090 Lifter,Valve

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To identify which of the valves of an engine is accompanied with a noisy valve lash adjuster, place a hose or tubing at each intake and exhaust valve during a running of the engine then listen to the noise at one end of the hose or tubing. Otherwise, if you take off the rocker arm cover and with the engine running, touch each of the valve spring retainers; you will feel the faulty lash adjuster through the retainer as the valve seats. As Schaevitz's warning suggests however, if adjustments are correct, dirt trapped between the plunger and lash adjuster body is often the root cause. Start with the L4 rocker arm cover followed by the intake manifold; L4 engines should have the pushrod cover also removed. Turn the nut of the rocker arm counterclockwise to get the rocker arm out of the pushrod area and then remove the pushrod. In removing the lash adjusters, one can use a special lash adjuster removal tool, or even just a sharp scribe so as not to mar the lash adjuster body in any way. Retain the lash adjusters for the purpose of reassembly in their respective sites. To dismantle a valve lash adjuster, apply pressure to the top of the plunger by inserting a pushrod to remove the pushrod seat retainer, pushrod seat, and metering valve by using a small screwdriver. The following components should be taken out, namely the plunger, ball check valve, plunger spring; the ball check valve will require use of a small screwdriver to remove in addition to the spring. Check all parts for signs of wear and where possible have the complete lash adjuster assembly replaced if any defects are noticed on the ball, particularly if there are flat spots on it. Each lash adjuster should have its camshaft lobe mating surface checked for scoring, wear, or erosion, any such texture on the lash adjuster body requiring its replacement while wear in the lash adjuster bore is rare. For reassembly, place the check ball on the small hole in the bottom of the plunger, insert the check ball spring on the seat in the ball retainer and fix the retainer. After that, insert the plunger spring over the ball retainer, turn the lash adjuster body upside down and make certain the oil holes are in proper orientation to each other before flooding the compartment with SAE 10 oil. Last but not least, fit the metering valve and the pushrod seat; push the seat in place and fix it by fitting the pushrod seat retainer. They must be replaced on their original bores and their surfaces should be treated with Molykote or an equivalent lubricating alloy before reinstalling them by reversing the above process.

To isolate a noisy valve lash adjuster, place a length of hose or tubing near each valve while listening at the other end, or remove the rocker arm cover and touch each valve spring retainer with the engine idling; a defective lash adjuster will be noticeable through the shock felt at the retainer as the valve seats. The most common cause of noise is dirt trapped between the plunger and lash adjuster body. Begin by removing the rocker arm cover, then loosen both rocker arm bolts at the cylinder with the noisy lash adjuster and rotate the rocker arms away from the pushrods before removing the pushrod guide plates and pushrods. Next, take off the intake manifold and the pushrod cover. Unscrew the pushrod cover studs to remove the lash adjuster guide retainer and then the lash adjuster guide, keeping them in order if multiple guides are removed. Lash adjuster extraction can be done using a special hydraulic tool, but often a small magnet or fingers suffice on newer engines without varnish buildup; a small scribe may also help, but avoid using pliers unless replacing the lash adjuster to prevent damage. Store the lash adjusters in a clearly labelled box to ensure they are reinstalled in their original bores. Replacing a worn lash adjuster is generally easier than repairing a defective one, as internal components are not sold separately. If cleaning a dirty lash adjuster, disassembly may restore normal function. When installing, ensure lash adjusters are placed back in their original bores, coating each foot with moly-base grease or engine assembly lube, and lubricate the bearing surfaces of the lash adjuster bores with engine oil. Install the lash adjusters with the oil orifice facing the front of the engine, followed by the lash adjuster guides and retainers. Reinstall the pushrods, guide plates, rocker arms, and retaining bolts, ensuring each pair of lash adjusters is on the base circle of the camshaft before tightening the bolts to the specified torque. Finally, reinstall the pushrod cover, intake manifold, rocker arm cover, and air cleaner.

Before installing new or used lifters in the engine, lubricate the roller and bearings of the lifter with No. 1052365 lubricant or an equivalent lubricant.

Start by removing the rocker arm covers and positioning the number one piston at TDC (Top Dead Center) on the compression stroke.

Lubricate the bearing surfaces of the lifter bores with engine oil, then install the lifters with the oil orifice facing the front of the engine. Follow with the installation of the lifter guides and retainers, then the pushrods, pushrod guides, rocker arms, and rocker arm retaining bolts, ensuring each pair of lifters is on the base circle of the camshaft before tightening.

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.

After installing the camshaft, install the timing chain and sprockets. Lubricate the lifters with clean engine oil and install them in the block. Finally, change the oil and install a new oil filter before starting and running the engine.

Disconnecting the engine's electrical connectors from the distributor is necessary to prevent any interference or signals from the distributor that might affect the accuracy of the camshaft lobe lift measurement.

The camshaft should always be thoroughly inspected before installation, and endplay must be checked prior to removal.

Begin by removing the intake manifold, valve covers, rocker arms, pushrods, timing chain, and cylinder heads, along with the radiator, air conditioning condenser, and camshaft position sensor.

Clean the lifters and check for scuffing, score marks, and uneven wear. If the lifters are worn or damaged, it's advisable to replace them along with the camshaft. For roller lifters, also check the rollers for wear and damage.

Clean and dry the lifters, examining them for wear and checking for flat spots. Worn lifters must be replaced with new ones, and the camshaft should also be replaced.

If the cam lobe lift is less than specified, you should install a new camshaft.

When installing the camshaft, it should be carefully slid into the engine while supporting it near the block to prevent damage to the bearings.

After installing the camshaft, you should install the thrust plate and tighten the bolts. Reinstall the oil pump drive.

After installing the camshaft, you should install the thrust plate and tighten the bolts. Reinstall the oil pump drive.

Stuck lifters may be freed by applying carburetor cleaner around the body and moving the lifter up and down.

Measurements of the diameter of each camshaft journal and the lift of each camshaft lobe should be taken using a micrometer. These measurements should be compared with the specifications to determine if they fall within the specified values.

Various methods can be used to extract the lifters from the bores, depending on the specific situation and available tools.

Yes, disassembling and cleaning a dirty lifter may restore normal operation.

Begin by removing the rocker arm cover, followed by the intake manifold and the pushrod cover.

Camshaft bearing replacement requires special tools and expertise, so it is advisable to take the block to an automotive machine shop for proper handling.

Replace the camshaft if it exceeds 0.001-inch out-of-round.

The most likely cause of a noisy valve lifter is excessive wear at the lifter foot and camshaft lobe, or wear or contamination of the internal components.