Chevrolet 12599650 Arm,Valve Rocker

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Ensuring a specific cylinder is at TDC and the lifters for that cylinder are on the base circle of the camshaft is important to prevent valve and piston interference when removing rocker arms and pushrods.

After detaching the valve covers, proceed to loosen and remove the rocker arm stud nuts.

Rotate the crankshaft to TDC on the compression stroke for the number one piston and tighten the intake valve rocker arms for specific cylinders. Rotate the crankshaft 360 degrees and tighten the intake valve rocker arms for other cylinders.

During inspection, each rocker arm should be checked for wear, cracks, and damage, as well as the rocker arm pivot area.

After starting the engine, you should check for valve cover leaks and valvetrain noise.

To remove rocker arms and pivot balls, first loosen the rocker arm bolts and then remove the rocker arm nuts, rocker arms, and pivot balls. Carefully store them in marked containers for proper reinstallation.

During this process, you should inspect rocker arms for wear, cracks, and damage, particularly in areas where they contact pushrods and valve stems.

To remove the valve covers, start by detaching them from the cylinder heads. Proceed to loosen and remove the rocker arm stud nuts, starting at the front of one cylinder head. Store these nuts separately in marked containers to ensure proper reinstallation. For models through 1998, if only the pushrods need removal, loosen each nut just enough to rotate the rocker arms aside for pushrod removal. In 2000 and later models, roller-rocker arms are retained by bolts instead of pivot balls. Lift off the rocker arms and pivot balls, and store them with the nuts for later reinstallation. Remove the pushrods and store them separately to avoid mixing them up during installation, utilizing a perforated cardboard box for organized storage. Inspect each rocker arm for wear, cracks, and damage, focusing on the areas where pushrods and valve stems contact the rocker arm faces. Ensure the hole at the pushrod end of each rocker arm is open and check the rocker arm pivot area for wear, cracks, and galling. If any rocker arms are worn or damaged, replace them along with new pivot balls, especially on 2000 and later models with roller rocker arms. Inspect the pushrods for cracks and excessive wear, checking for bending by rolling them on a flat surface. To install, lubricate the lower end of each pushrod with clean engine oil or moly-base grease, seat them in their original lifter positions, and apply moly-base grease to valve stem and pushrod ends before positioning the rocker arms over the studs. Install pivot balls and nuts, ensuring the flat side of each nut faces the pivot ball. Tighten the rocker arm nuts. Reassemble the remaining components in reverse order, starting the engine and checking for valve cover leaks and valvetrain noise. Note that valve adjustment is not required for most models; however, specific instructions for valve adjustment on 1994 VIN Z engines are provided, involving setting the engine to TDC, aligning timing marks, and adjusting rocker arm nuts for specified valves at TDC for each cylinder.

Apply engine assembly lube to the valve stems and pushrod ends to prevent damage.

To remove rocker arms and pivot balls, first loosen the rocker arm bolts and then remove the rocker arm nuts, rocker arms, and pivot balls. Carefully store them in marked containers for proper reinstallation.

Storing the rocker arm stud nuts separately in marked containers ensures proper reinstallation.

The pushrods should be inspected for cracks, excessive wear, and bending.