GM 12522105 Arm Kit,Valve Rocker

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First, remove the valve cover from the cylinder head to inspect and take out rocker arms and pushrods. It is important to make sure that a specific cylinder is at Top Dead Center (TDC) and that the lifters for this cylinder are on base circle of camshaft when removing them. To show TDC, use a plastic pen through the spark plug hole to raise piston on its highest point by rotating the crankshaft. Loosen rocker arm bolts, take off rocker arm nuts, rocker arms and pivot balls ensuring they are carefully stored in marked containers. Rotate the rocker arms aside for an easy pushrod removal. Also, don't forget about the pushrod guides if necessary remove them marking them for proper reinstallation. Look for wear, cracks, or damage especially where they contact with pushrods and valve stems on rocker arms. Inspect the rocker arm pivot area for wear, cracks or galling and make sure that each rocker arm has an open pushrod-end hole. Replace damaged or worn out rocker arms with new pivot balls as required. Lubricate lower ends of pushrods with engine oil or moly-based grease before installing them into their original locations and checking that they sit properly in lifter socket. Apply moly-based grease on valve stem ends and upper pushrod ends before positioning you're your installing bolts for aileron activator. With care, install pivot balls and bolts then tighten rocker arm nuts while no valve spring load is present on it; replace retainer bolt hand-tight before torquing down to specified amounts using a torque wrench set at 14-15 lb-ft; replace retainer bolt hand-tight before torquing down to specified amounts using a torque wrench set at 14-15 lb-ft. In later models align tab on roller rocket pivot with slot in cylinder head casting protrusion; reinstall valve cover after tightening rocker arms then check for oil leaks or valve train noises after starting the engine.

To remove the valve covers, first detach them from the cylinder heads. Proceed by loosening and removing rocker arm stud nuts, starting from the front of one cylinder head. Keep these nuts in separate containers that are labeled so you can put them back correctly. On 1998 models and prior ones, in case only pushrods have to be removed, loosen each nut just enough to enable you rotate the rocker arms out of the way for pushrod removal. Instead of using pivot balls, roller-rocker arms on model year 2000 and later are retained by bolts. Put away rocker arms and pivot balls with nuts for reinstallation later on. Take out pushrods and keep them apart to avoid mix up during installation utilizing a perforated cardboard box which allows organized storage. Examine each rocker arm for wear, cracks or any other damage focusing on areas where rocker arm faces contact with pushrods and valve stems. Make sure that hole at the pushrod end of each rocker arm is open and inspect rocker arm pivot area for wear, cracks or galling. In particular, replace all worn roller rocker arms along with new pivot balls on 2000 and newer models. Check whether there are cracks or excessive wear on pushrods by rolling them on a flat surface to see if they are bent. To install, lubricate lower end of every single pushrod using clean engine oil or moly-base grease; seat in their original lifter positions; apply moly-base grease to valve stems as well as pushrod ends before placing the rocker arms over studs. Install pivot balls and nuts making sure that flat side of each nut faces pivot ball. Tighten down the rocker arm nuts properly. Reverse order reassemble remaining components; start engine then check for valve cover leaks as well as valvetrain noise (Haines). Note too that most models do not require a valve adjustment except specific instructions provided here for valve adjustment on 1994 VIN Z engines including setting the engine to TDC, aligning timing marks, and adjusting rocker arm nuts for specified valves at TDC for each cylinder.

When installing pivot balls and nuts, ensure the flat side of each nut faces the pivot ball.

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.

Only loosen each nut enough to rotate the rocker arms to the side for push rod removal.

Reinstall the rocker arm covers, start the engine, check for unusual valve train noises, and inspect for oil leaks at the rocker arm cover joints.

Reassemble the remaining components in reverse order.

When removing pushrod guides, mark them for proper reinstallation. This is important to ensure they are placed back in their original positions.

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

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.