Hummer 12698945 Lifter Assembly, Vlv (Non Afm)

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Disconnect the cable from the negative battery terminal, then rotate the engine until the #1 cylinder is at Top Dead Center (TDC) on the compression stroke. Remove the valve cover(s) and the timing belt. Rotate the crankshaft 60 degrees counterclockwise to prevent the valves from possibly hitting the pistons, then remove the camshaft sprocket bolts and sprockets. Each camshaft bearing cap has a double-digit identifying number etched on it, with specific numbering for the exhaust and intake camshaft bearing caps on both sides of the engine. Loosen the camshaft bearing cap bolts progressively by half a turn at a time to gradually release the pressure of the valve springs. Withdraw the caps, noting their markings and the presence of locating dowels, then remove the camshafts and front oil seals, identifying the intake and exhaust camshafts by their respective stamps. Use twelve small, clean containers to store each Lash Adjuster, ensuring they are not interchanged. With the camshafts and Lash Adjusters removed, check for signs of wear and measure the outside diameter of each Lash Adjuster at multiple points. Visually examine the camshaft lobes and bearing journals for wear or pitting, and measure the diameter of each journal. To check the bearing journal running clearance, clean all bearing surfaces, install the camshafts and bearing caps with Plastigage across each journal, then measure the width of the compressed strands. If any bearing is worn beyond specified limits, install a new camshaft and repeat the check. For camshaft endplay, clean the bearing surfaces, install the camshafts and bearing caps, then measure the endplay using a dial indicator. If the endplay exceeds specified limits, install a new camshaft. Confirm the crankshaft is positioned at 60 degrees BTDC, then oil the cylinder head Lash Adjuster bores and install the Lash Adjusters in their original positions. Oil the camshaft bearing surfaces and install the camshafts in their original locations, ensuring the pins are positioned correctly. Apply silicone sealer to the forward edge of the front bearing caps and check that all mating surfaces are clean. Oil the camshaft journals and lobes, then install each camshaft bearing cap, ensuring the numbered side faces outwards. Tighten the camshaft bearing cap bolts in sequence until each cap touches the cylinder head, then to the specified torque. Coat the lip of the camshaft seal with clean engine oil, press it into the end of the bearing cap, and use a seal driver to ensure it is flush and square. Finally, install the camshaft sprockets to the correct camshafts, ensuring the camshaft pin is in the same numbered slot on the sprocket it was removed from, and tighten the new camshaft sprocket bolt to the specified torque.

If the camshaft is being replaced, always install new Lash Adjusters as well, as old Lash Adjusters should not be used with a new camshaft. The engine should be removed for this procedure. Begin by having the air conditioning system discharged by a technician, then relieve the fuel system pressure and disconnect the negative battery terminal. Drain the cooling system and remove the radiator, followed by the air conditioning condenser and the auxiliary automatic transmission fluid cooler if equipped. Remove the valve covers, intake manifold, and valve Lash Adjuster oil manifold, then take out the valve Lash Adjuster follower guide and rocker arms with pushrods. Next, remove the oil pump, balance shaft chain, timing chain, and camshaft position actuators, followed by the cylinder heads. Store the Lash Adjusters in a clearly labeled box to ensure they are reinstalled in their original locations, and remove the Lash Adjuster retainers and Lash Adjusters, taking care not to withdraw the camshaft with the Lash Adjusters in place. Mark and inspect the Lash Adjusters after removal, and if they are stuck due to gum and varnish, use appropriate tools to extract them. Avoid using pliers unless the Lash Adjusters are to be replaced. Remove the bolts and camshaft retainer plate, noting the orientation, then thread a bolt into the camshaft sprocket bolt hole for easier removal. Carefully pull the camshaft out while supporting it near the block to prevent damage to the bearings. Measure the camshaft lobe height and base circle to determine lobe lift, and compare the results to specifications; if the lobe lift is less than specified, a new camshaft should be installed. After cleaning the camshaft, inspect the bearing journals for wear and damage, and measure them with a micrometer. Check the camshaft lobes for discoloration and wear, and if they are in good condition, the camshaft can be reused. Clean the Lash Adjusters thoroughly and check for wear, ensuring that used roller Lash Adjusters cannot be reinstalled with a new camshaft. Lubricate the camshaft bearing journals and lobes with assembly lube before sliding the camshaft into the engine, supporting it carefully. Apply a non-hardening thread-locking compound to the camshaft retainer bolts and install them after allowing the compound to cure. Install the camshaft thrust plate and tighten the bolts, ensuring the gasket surfaces are clean. Proceed to install the timing chain, balance shaft chain, and oil pump. Lubricate the Lash Adjusters with clean engine oil and install them in the retainers, aligning them properly, and tighten the retainer bolts. Complete the installation in reverse order of removal, refill the cooling system, change the oil, and install a new oil filter before having the air conditioning system evacuated, recharged, and leak tested.

Where a camshaft is being changed, it is recommended that new Lash Adjusters should be fitted, and the old Lash Adjusters should not be retained to work on a new camshaft. Start with the intake manifold or the supercharger, the valve covers and rocks, along with the pushrods and the timing chain, timing chain tensioner, heads, oil pan, oil pump, and oil deflector, the radiator and condenser for the air conditioning, among with the Camshaft Position sensors. When doing away with the Lash Adjusters, pack them in a separate case and clearly label it, to avoid mixing or installing from a different set. Lash Adjuster retainers as well as the Lash Adjusters have to be removed but the Lash Adjusters must be cleaned before being stored; each Lash Adjuster retainer contains four individual Lash Adjusters that must be placed back in their correct positions if they will be reused. Inasmuch as gum and varnish may hinder the Lash Adjusters and stick them in place, they can be removed by a specialized tool or, in extreme circumstances, a magnet or the bare fingers. Next, one needs to take out the bolts and the camshaft retainer plate to see which side is to face the block. Take the old camshaft position actuator solenoid valve and put it back in or put three very long bolts in the camshaft sprocket bolt holes so they can be used as a handle to remove the camshaft from the block. With the camshaft subsidence largely undamaged, gradually unwind the strength and supporting the camshaft near the block. For installations, the bearing journals and the cam lobes should be lubricated with the camshaft and the Lash Adjuster assembly lube practices putting the camshaft under the engine while still supporting it near the block. With the dowel pin at the 3 O'Clock position, fit the camshaft retainer plate and tighten the camshaft retainer plate bolts to the next torque specification, check the gasket surface is clean. Then fitting of the timing chain and sprockets as well as the CMP sensor. Use clean engine oil to lube the faced sides of the Lash Adjusters and then fit them to the Lash Adjuster retainer, ensure the flats are aligned, then fit the retainer and Lash Adjusters onto the block as a unit, where original Lash Adjusters are returned to their original position where possible. Tighten the Lash Adjuster retainer bolts to requirement torque and then proceed to reinstall the components in the vice versa manner to this process. It is suggested that before the commencement of the engine, the oil should be changed and a new oil filter fitted in the engine.

When the camshaft is being replaced it is advisable to replace the Lash Adjusters as well, because new Lash Adjusters are not supposed to be used when the camshaft is also new. The removal of the camshaft and Lash Adjuster is well illustrated by the following step by step process recommended by the factory. First, it is possible to remove the engine, but it is not obligatory; however, it will make the process easier. Second, it is the intake manifold or supercharger, the valve covers, rocker arms, pushrods, timing chain, timing chain tensioner, cylinder heads, oil pan, oil pump, and oil deflector. Lash Adjusters also should be stored in a box marked clearly before they are removed so that they can be returned to the storage locations they occupied after delivery. The Lash Adjuster retainers and Lash Adjusters can then be removed as an assembly and as much as possible bearing markings for reuse are identified. After that, the camshaft retainer plate bolts should be removed, paying attention to the positions of the plate. Long bolts or a single bolt can be turned into the camshaft sprocket bolt hole to help in extraction of the camshaft. The camshaft should be gently slid out, where it must be supported close to the block in a bid to avoid marring the bearings. Before installing the camshaft, the bearing journals as well as the lobes area should be coated with assembly lube; this ensures that the camshaft is slid into the engine while propping it to reduce of bearing damage. The camshaft should be rotated in order to align the dowel pin and then the retainer plate should be fitted and fixed in place. Timing chain and sprockets should then be fitted in its proper place. Lash Adjusters must be oiled with clean engine oil and then placed in the retainers as require while making certain that they are well aligned. Retainers and Lash Adjusters should be mounted modulo, namely, if some Lash Adjusters were returned they must be placed on the same bank. Finally, the Lash Adjuster retainer bolts should be tightened and the rest of the procedure is but the reversal of the list above. Last but not the least, before starting of the car's engine one should change the oil and also to replace the oil filter.

In any case of a camshaft replacement, it is recommended to replace the Lash Adjusters also. It is recommended that old Lash Adjusters should not be used on a new camshaft. Starting from the electricity, remove the cable, release the pressure of the fuel system as well as the removal of the radiator. If installed, then slide out the auxiliary automatic transmission fluid cooler and disconnect power steering cooler. Second it will be necessary to come to an end the removal of the air conditioning condenser, a valve, the upper head, the intake manifold with the heads of bolts, the hydraulic Lash Adjusters, the pushrods, the timing chain, the sprockets fastened to the engine bulkhead, and heads of the cylinders. When it is time to remove the Lash Adjusters provide for the reception in a marked box so that they can be placed in the right position after repair. Lash Adjuster retainers and Lash Adjusters should be removed and it is important to ensure they are clean, it should also be noted that each of the retainers contains four separate Lash Adjusters which must be replaced back in the same positions if they are to be re-used. If for some reason the Lash Adjusters got stuck due to the build up of gum and or varnish various methods of extraction can be used, such as with the aid of an L.H. tool, a small magnet or machinist's scribe. Pliers should not be used except when Lash Adjusters are to be replaced as this can cause damage to them. Unbolt the camshaft retainer plate and the camshaft, and note the direction of the plate as it faces the block; thread a bolt in the sprocket hole of the camshaft where the old bolt is removed to serve as a camshaft handle. With caution and gradual force remove the camshaft out, while holding it close to the block to avoid causing problems to the bearings. Estimate the camshaft lobe height and base circle to understand the lift of the lobe and write the figures for future use. Following the lobe lift check, check it with the specified figures; should the lobe lift be 0.02 inches below the specified figure then cam lobe wear has taken place and the car will probably require a new camshaft. It is proper to check out the bearing journals for wear and damage and then measure them across their diameter with a view of identifying excessive wear or out-of-round situations after cleaning the camshaft. Finally examine the camshaft lobes for any discoloration, for signs of score marks or uneven wear; if the lobes are healthy the camshaft can be used again. Lash Adjusters should also be cleaned and inspected for signs of wear especially on part that rotates in the form of rollers which should be without or with minimal end play. roller Lash Adjusters, once used cannot be replaced with a new camshaft and therefore when using a new camshaft, always use new Lash Adjusters. As for the installation, before that, the camshaft bearing journals and lobes should be lubricated, and then the camshaft is to be inserted into the engine with the help of a supporting block near the block. Rotate the camshaft in a way that the dowel pin is placed at the '3' mark, put the camshaft thrust plate and fasten all the bolts to the recommended torque. Replace the timing chain and sprockets and also the camshaft position sensor, new O-ring ought to be used for this installation. Lightly coat the Lash Adjusters with fresh engine oil and then fitting them again in lift retainers in a precise manner. There are usually reusable/replaceable Lash Adjusters and because of this, the retainer and the Lash Adjusters should be installed together into the engine block with the original Lash Adjusters being placed in their respective locations again. Torque the Lash Adjuster retainer bolts to the manufacturer recommended torque then to complete the procedure reverse the whole process. Ensure usage of sufficient coolant before the engine is on, replace engine oil and fit a new oil filter.

A special camshaft holding tool Number GM# J-44221 or equivalent is necessary for this action. When the cam sprocket has been taken off, do not turn the crankshaft this may cause improper timing of the engine with consequent damages of the engine. Start by unwiring the valve cover and the spark plugs so as to be in a position to rotate the engine. Turn the engine clockwise until grooves for sprockets match with a black link on the chain; the flats at the back of the camshafts will be up if the engine is at the Top Dead Centre for cylinder number one. Take out the camshaft sprocket bolts, and then do so carefully with the sprockets of the camshafts. Make sure the camshaft caps have been scribed; if they haven't been scribed, scribe them with paint before you remove them, so that it will be easier for you to align them later. Loosen and take out the camshaft cap bolts and in slow procedures extract the camshafts with caution to ensure that each of them is not mixed up. This is a good time to lift out the rocker arms and the lash adjusters and it will be wise to ensure that set is orderly set aside to be re-fixed later. When camshafts are removed they should be cleaned with solvent and dried, Check each camshaft for; scored journals, heat discoloration, score marks, chipped areas, pitting and uneven wear, damaged sprocket locator slots and damaged threads. You can use micrometer to take measurement of bearing journals looking for elevated levels of wear or out-of-round. To replace it, the lash adjusters and rocker arms must be immersed in clean engine oil, before being placed back in their positions. Ensure that the camshaft is clean then apply some drop of clean engine oil on the camshaft before putting it on the right place on the cylinder head and then fitting the holding tool for the camshaft correctly. Replace all camshaft caps in their proper positions and tighten them using your hands, afterwards using a pattern tighten the caps to the prescribed torque. Take out the holding fixture, put the sprockets on the camshafts in the right way, and screw the bolts to the suggested level of tension. However, after removing the crankshaft pulley bolt, positioned with large breaker bar and socket on it, rotate the crankshaft 720 degrees the crankshaft twice and again examine the sprocket and chain and see to it that the darkened links lines up with the sprocket marks. Any kind of grinding or any feeling of friction when working on the crankshaft should indicate that operations have to be ceased. Finally, fit back the spark plugs and the valve cover in position.

In any case of a camshaft replacement, it is recommended to replace the Lash Adjusters also. It is recommended that old Lash Adjusters should not be used on a new camshaft. Starting from the electricity, remove the cable, release the pressure of the fuel system as well as the removal of the radiator. If installed, then slide out the auxiliary automatic transmission fluid cooler and disconnect power steering cooler. Second it will be necessary to come to an end the removal of the air conditioning condenser, a valve, the upper head, the intake manifold with the heads of bolts, the hydraulic Lash Adjusters, the pushrods, the timing chain, the sprockets fastened to the engine bulkhead, and heads of the cylinders. When it is time to remove the Lash Adjusters provide for the reception in a marked box so that they can be placed in the right position after repair. Lash Adjuster retainers and Lash Adjusters should be removed and it is important to ensure they are clean, it should also be noted that each of the retainers contains four separate Lash Adjusters which must be replaced back in the same positions if they are to be re-used. If for some reason the Lash Adjusters got stuck due to the build up of gum and or varnish various methods of extraction can be used, such as with the aid of an L.H. tool, a small magnet or machinist's scribe. Pliers should not be used except when Lash Adjusters are to be replaced as this can cause damage to them. Unbolt the camshaft retainer plate and the camshaft, and note the direction of the plate as it faces the block; thread a bolt in the sprocket hole of the camshaft where the old bolt is removed to serve as a camshaft handle. With caution and gradual force remove the camshaft out, while holding it close to the block to avoid causing problems to the bearings. Estimate the camshaft lobe height and base circle to understand the lift of the lobe and write the figures for future use. Following the lobe lift check, check it with the specified figures; should the lobe lift be 0.02 inches below the specified figure then cam lobe wear has taken place and the car will probably require a new camshaft. It is proper to check out the bearing journals for wear and damage and then measure them across their diameter with a view of identifying excessive wear or out-of-round situations after cleaning the camshaft. Finally examine the camshaft lobes for any discoloration, for signs of score marks or uneven wear; if the lobes are healthy the camshaft can be used again. Lash Adjusters should also be cleaned and inspected for signs of wear especially on part that rotates in the form of rollers which should be without or with minimal end play. roller Lash Adjusters, once used cannot be replaced with a new camshaft and therefore when using a new camshaft, always use new Lash Adjusters. As for the installation, before that, the camshaft bearing journals and lobes should be lubricated, and then the camshaft is to be inserted into the engine with the help of a supporting block near the block. Rotate the camshaft in a way that the dowel pin is placed at the '3' mark, put the camshaft thrust plate and fasten all the bolts to the recommended torque. Replace the timing chain and sprockets and also the camshaft position sensor, new O-ring ought to be used for this installation. Lightly coat the Lash Adjusters with fresh engine oil and then fitting them again in lift retainers in a precise manner. There are usually reusable/replaceable Lash Adjusters and because of this, the retainer and the Lash Adjusters should be installed together into the engine block with the original Lash Adjusters being placed in their respective locations again. Torque the Lash Adjuster retainer bolts to the manufacturer recommended torque then to complete the procedure reverse the whole process. Ensure usage of sufficient coolant before the engine is on, replace engine oil and fit a new oil filter.

Complete the installation by reversing the removal steps, and before starting the engine, change the oil and install a new oil filter.

The first step is to detach the valve covers from the cylinder heads and remove the camshafts.

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.

Relieve the fuel system pressure and disconnect the negative battery terminal.

Store lifters in a segregated box to maintain their positions for reinstallation.

During inspection of the camshaft, you should: 1. Clean the lifter and camshaft with solvent. 2. Check for wear and damage on the lifter and camshaft. 3. Measure the journals and cam lobes for wear. 4. Replace the camshaft and bearings if they are damaged.

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

If reusing the lifters, you should install them in their original bores and coat them with assembly lube.

The lifters should be stored in a clearly labeled box before removing them.

Remember that these engines do not have valve adjustments, so excessive wear or damage in the valve train can lead to increased valve clearance and noise during operation.

Begin by removing the valve cover and the spark plugs to facilitate engine rotation.

Inspect the camshaft and bearings for wear, pitting, and damage, measuring the bearing journals with a micrometer. Clean and check conventional lifters for wear, ensuring they are slightly convex; if any are concave or damaged, replace them along with the camshaft. For roller lifters, ensure they turn freely and check for wear.

Inspect bearing journals for wear and damage, and check camshaft lobes for discoloration and uneven wear. Clean and inspect lifters for damage, ensuring they turn freely.

Remove the bolts and the camshaft retainer plate, noting the orientation. Thread a bolt into the camshaft sprocket bolt hole to assist in removal. Carefully pull the camshaft out, supporting it near the block to prevent damage to the bearings.

Common causes of noisy lifters include dirt trapped inside and insufficient oil. It is important to check the oil for contamination, level, cleanliness, and viscosity before concluding that the lifters are at fault.

Complete the installation by reversing the removal steps. Before starting the engine, refill the cooling system, change the oil, and install a new oil filter.

If reusing the lifters, you should install them in their original bores and coat them with assembly lube.

The steps to remove the camshaft are as follows: 1. Remove the intake manifold. 2. Remove the rocker arms. 3. Remove the pushrods. 4. Remove the timing chain. 5. Remove the camshaft sprocket. 6. Remove the balance shaft drive gear. 7. Remove the fan, radiator, and condenser. 8. Store the lifters in a labeled box. 9. Remove the lifter retainer. 10. Extract the lifters from the bores using a special tool, magnet, or your fingers. 11. Remove the camshaft retainer plate. 12. Use three 6-inch long, 5/16-18 bolts as a handle to remove the camshaft from the block.

During inspection, visually examine the cam lobes and bearing journals for wear, scoring, pitting, galling, overheating evidence (discoloration), and flaking of the hardened surface.

To inspect the camshaft, the lobe height and base circle should be measured to determine the lobe lift. The results should be compared to the specifications, and the camshaft should be replaced if necessary. The camshaft bearing journals should also be inspected for wear and damage, and measured with a micrometer. The camshaft lobes should be checked for discoloration, score marks, chipped areas, and uneven wear.

To install the camshaft into the engine, slide the camshaft carefully into place.

The procedure is for removing lifters from an engine.

Earlier models have conventional lifters, while later engines feature roller lifters, which are secured by a guide plate and lifter guides that must be removed to access the lifters.

During inspection of the camshaft, you should: 1. Clean the lifter and camshaft with solvent. 2. Check for wear and damage on the lifter and camshaft. 3. Measure the journals and cam lobes for wear. 4. Replace the camshaft and bearings if they are damaged.

Before starting the engine after camshaft installation, it is essential to change the oil and install a new oil filter.

Install the retainer and lifters as an assembly, returning original lifters to their original locations if reused, and tighten the lifter retainer bolts to the specified torque.

After removing the lifters, you should clean them and inspect them for scuffing, score marks, and uneven wear. Additionally, check the rollers for wear and damage. Replace the lifters if necessary.

Common causes of noisy lifters include dirt trapped inside and insufficient oil flow, viscosity, or pressure. It is important to check the oil for fuel contamination, correct level, cleanliness, and viscosity before making any judgments about the lifters.

After installing the camshaft, you should:1. Refill the cooling system.2. Change the engine oil and filter.3. Start the engine and check for leaks.

After installing the camshaft, the cooling system should be refilled, the oil should be changed, and a new oil filter should be installed before starting and running the engine.

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.

The camshaft can be removed by removing the lifters and camshaft retainer plate, and using a bolt as a handle to carefully pull it out.

The steps for installing the camshaft are as follows:1. Lubricate the camshaft bearing journals and cam lobes with assembly lube.2. Slide the camshaft into the engine.3. Install the camshaft thrust plate.4. Install the balance shaft drive gear.5. Install the timing chain and sprockets.6. Lubricate the lifters with clean engine oil.7. Install the lifters in the block.8. Complete the installation in reverse order of removal.

During inspection of the camshaft, you should: 1. Clean the lifter and camshaft with solvent. 2. Check for wear and damage on the lifter and camshaft. 3. Measure the journals and cam lobes for wear. 4. Replace the camshaft and bearings if they are damaged.

The rocker arms and lash adjusters can be lifted out if needed, and these parts should be laid out in order for reinstallation.

Before removing the camshaft, the radiator, auxiliary automatic transmission fluid cooler (if equipped), power steering cooler, air conditioning condenser, valve covers, intake manifold, rocker arms, pushrods, timing chain and sprockets, and cylinder heads need to be removed.

Common causes of noisy lifters include dirt trapped inside and insufficient oil. It is important to check the oil for contamination, level, cleanliness, and viscosity before concluding that the lifters are at fault.

After installing the camshaft, the cooling system should be refilled, the oil should be changed, and a new oil filter should be installed before starting and running the engine.

Turn the camshafts so the "flats" are facing up, then install the special camshaft timing clamp tool.

Inspect the camshaft and lifters for wear and measure the lifter bore and outside diameters, recording the results to determine clearance and compare to specifications for necessary replacements.

Reinstall the pushrods, pushrod guides, rocker arms, and rocker arm retaining bolts, tightening them to the specified torque.