Hummer 12721203 LIFTER ASM-VLV

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To check for a noisy valve lifter, you can use a mechanics stethoscope or a length of hose near each valve while listening for excessive clearance in the valvetrain. If a lifter is defective, it will be evident from the noise.

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

If the cam lobe lift is less than the specified value, it is recommended to install a new camshaft.

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.

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.

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.

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

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.

Before installing the camshaft, you should lubricate the camshaft bearing journals and lobes 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.

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.

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.

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.

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

The initial steps for checking camshaft lobe lift before removal involve removing the valve covers and loosening the rocker arm nuts to pivot the rocker arms for access to the pushrods. A dial indicator should be mounted on the engine, positioned directly above the first pushrod.