GM 12556295
Push Rods

Before replacing the valve Rocker Arm and push rod mark the components initially then sort them properly to ensure their correct restoration in the final assembly process. The repair must start by taking off the valve Rocker Arm cover and progressing to the valve Rocker Arm nuts and balls together with the valve rocker arms. The exhaust valve pushrods extend beyond the length of intake valve pushrods. After removing valve pushrods and Pushrod guides with valve Rocker Arm studs, you should clean and examine both rocker arms and pushrods. The installation of valve Rocker Arm stud-to-cylinder head threads requires gm U.S. P/N 12346004 or canada P/N 10953480 or equivalent sealant material. Install Pushrod guides together with valve Rocker Arm studs while tightening the studs until they reach 50 nm (37 ft. Lbs.). During the installation procedure remember that exhaust valve pushrods exceed the length of intake valve pushrods. The valve pushrods need installation before coating the valve Rocker Arm surfaces along with the valve Rocker Arm ball bearing components using gm u.s P/N 12345501, canada P/N 992704, or equivalent. Put the valve rocker arms along with valve Rocker Arm balls and valve Rocker Arm nuts into place before tightening them slowly to 25 nm (18 ft. Lbs.) to ensure the tips of the rocker arms remain on top of the valve tips. Place the valve Rocker Arm cover as your last step.

You should start valve Rocker Arm and push rod replacement by taking off the Rocker Arm cover and keeping original positions of the rocker arms with pushrods and pivot support in a rack. The procedure starts with bolt removal of the rocker arms which leads to the elimination of both rocker arms and Rocker Arm pivot support and ends with Pushrod removal. Clean and perform inspections on the rocker arms and pushrods as per need. The procedure calls for clean engine oil application to both rocker arms and pushrods while the flange of the Rocker Arm bolts should be lubricated as well. After setting the pushrods into proper position between the valve lifter sockets and Rocker Arm ends keep the Rocker Arm bolts loose until completion. Directionally spin the Crankshaft until the number one Piston reaches the tdc point of compression providing the cylinder number one rocker arms settle at zero lobe lift along with the Crankshaft sprocket key stopping at the 1:30 position. The engine should stay at this position to tighten Rocker Arm bolts for exhaust valves in cylinders 1, 2, 7, 8 while tightening intake valves in cylinders 1, 3, 4, 5 to 30 nm (22 ft. Lbs.). Tighten the bolts securing the intake or exhaust valves of cylinders 3 to 6 to 30 nm (22 ft. Lbs.) after rotating the Crankshaft 360 degrees. Mount the Rocker Arm cover in its appropriate position.

First remove the Rocker Arm cover prior to arranging the rocker arms and pushrods along with pivot support in a rack according to their original position. Remove the Rocker Arm bolts from the sequence before you extract the components which include rocker arms and Rocker Arm pivot support and pushrods. When needed inspect the rocker arms and pushrods before conducting cleaning procedures on them. Clean engine oil should be used to lubricate rocker arms before installation while the flange of Rocker Arm bolts requires separate lubrication. The installer should position the Rocker Arm pivot support where pushrods sit properly within valve lifter sockets and Rocker Arm ends before delaying bolt tightening. Position the Crankshaft sprocket key to the 1:30 spot while the number one Piston reaches top dead center (TDC) of the compression stroke. The engine position allows bolt tightening for exhaust valves on cylinders 1, 2, 7, 8 to 30 nm (22 ft. Lbs.) while intake valves on cylinders 1, 3, 4, 5 receive the same torque value. Follow the first step by turning the Crankshaft by 360° before applying torque of 30 nm (22 ft. Lbs.) to the Exhaust Valve Rocker Arm bolts of cylinders 3, 4, 5, and 6 and the Intake Valve Rocker Arm bolts of cylinders 2, 6, 7, and 8. Apply the last step by installing the Rocker Arm cover.

Before replacing the valve Rocker Arm and push rod mark the components initially then sort them properly to ensure their correct restoration in the final assembly process. The repair must start by taking off the valve Rocker Arm cover and progressing to the valve Rocker Arm nuts and balls together with the valve rocker arms. The exhaust valve pushrods extend beyond the length of intake valve pushrods. After removing valve pushrods and Pushrod guides with valve Rocker Arm studs, you should clean and examine both rocker arms and pushrods. The installation of valve Rocker Arm stud-to-Cylinder Head threads requires gm U.S. P/N 12346004 or canada P/N 10953480 or equivalent sealant material. Install Pushrod guides together with valve Rocker Arm studs while tightening the studs until they reach 50 nm (37 ft. Lbs.). During the installation procedure remember that exhaust valve pushrods exceed the length of intake valve pushrods. The valve pushrods need installation before coating the valve Rocker Arm surfaces along with the valve Rocker Arm ball bearing components using gm u.s P/N 12345501, canada P/N 992704, or equivalent. Put the valve rocker arms along with valve Rocker Arm balls and valve Rocker Arm nuts into place before tightening them slowly to 25 nm (18 ft. Lbs.) to ensure the tips of the rocker arms remain on top of the valve tips. Place the valve Rocker Arm cover as your last step.

The first step involves removing the Rocker Arm cover where you must organize the rocker arms pushrods pivot support in a rack before their original position to begin the replacement process. Detaching the bolts on the Rocker Arm starts the procedure followed by separation of the Rocker Arm along with the pivot support before removal of the pushrods. You should clean and inspect both the rocker arms and the pushrods after cleaning. Applying clean engine oil to both rocker arms and pushrods should happen before installation as well as applying lubrication to the Rocker Arm bolt flange. The installation of Rocker Arm pivot support requires you to verify that pushrods properly fit in valve lifter sockets before adding pushrods to their final position. The pushrods must rest in proper position against the Rocker Arm ends before tightening the Rocker Arm bolts. The Crankshaft should be rotated until the number one Piston reaches top dead center (TDC) compression position while cylinder number one rocker arms should be off-lift lobe and the Crankshaft sprocket key needs to sit at the 1:30 position. Install both the bolts and rocker arms at this moment. Following the number one firing position the technician should apply 30 nm (22 ft. Lbs.) torque to all Rocker Arm bolts leading to cylinders 1, 2, 7 and 8 exhaust valves and to cylinders 1, 3, 4, 5 intake valves. Roll the Crankshaft 360 degrees before tightening the Rocker Arm bolts at 30 nm (22 ft. Lbs.) for cylinders 3, 4, 5, 6 exhaust valves and 30 nm (22 ft. Lbs.) for cylinders 2, 6, 7, 8 intake valves. Instillation of the Rocker Arm cover should be the final step.

Start by removing the Rocker Arm cover after which the entire assembly of rocker arms pushrods and pivot support should go on a rack to remember their positions. The first step of this replacement involves taking out the Rocker Arm bolts together with the rocker arms and Rocker Arm pivot support and pushrods. You should clean and inspect any needed rocker arms and pushrods. During reinstallation process apply engine oil on the rocker arms and pushrods together with oil on the flange section of the Rocker Arm bolts. The Rocker Arm pivot support must be installed while also verifying that pushrods settle into the valve lifter sockets before installing the pushrods which need to fit properly in the rocker arms. Do not tighten the bolts at this time. First install the rocker arms and bolts before rotating the Crankshaft until the number one Piston reaches the top dead center (TDC) of compression stroke with the Crankshaft sprocket key pointing at 1:30. Apply 30 nm torque to the bolts securing exhaust rocker arms on cylinders 1, 2, 7, 8 while using 30 nm torque to secure intake Rocker Arm bolts on cylinders 1, 3, 4, 5. The technician should turn the Crankshaft by 360 degrees before applying 30 nm (22 ft. Lbs.) torque to the exhaust Rocker Arm bolts for cylinders 3, 4, 5 and 6 and intake Rocker Arm bolts for cylinders 2, 6, 7 and 8. Put on the Rocker Arm cover as the last step.

Take out the valve rocker arm studs and pushrod guides, then clean and inspect the valve rocker arms and pushrods.

Begin by removing the valve rocker arm cover and placing the valve rocker arms, pushrods, and pivot support in a rack to maintain their original positions.

Rotate the crankshaft 360 degrees and then tighten the rocker arm bolts for cylinders 3, 4, 5, and 6 exhaust valves and for cylinders 2, 6, 7, and 8 intake valves, both to 30 N.m (22 lb ft).

Install the valve rocker arm cover.