GM 12576407
Camshaft Gear

The first step in Timing Chain and sprocket replacement includes taking out the Oil Pump before rotating the Crankshaft to match its marks with those on the cam and crank sprockets. After removing the Timing Chain, never turn the Crankshaft assembly to avoid piston assembly or valve damage. The first step includes removing camshaft sprocket bolts then proceeding with the removal of camshaft sprocket and Timing Chain. Utilizing the j8433 (Two Jaw Puller) as well as j41816-2 (Crankshaft End Protector) and j41558 (Crankshaft Sprocket Remover) will help you remove the Crankshaft sprocket followed by the removal of the Crankshaft sprocket key depending on requirements. Time the chain and its sprockets for any necessary cleaning or inspection process. Begin installation by inserting the key into the Crankshaft keyway and gradually push it forward until the key rests in both ends. Install the Crankshaft sprocket frontward on the Crankshaft with precise alignment of the key from the Crankshaft to the sprocket keyway before completing the installation using the j41665 (Crankshaft Balancer and Sprocket Installer). Rotate the Crankshaft sprocket so its alignment mark points to 12 o'clock while the camshaft sprocket locating pin should align with the sprocket alignment hole and the sprocket teeth should effectively engage the Timing Chain. Place the camshaft sprocket together with Timing Chain before adjusting either camshaft or Crankshaft sprockets to align their marks properly. The installation process ends by inserting the camshaft sprocket bolts then tightening them to 35 nm until they reach 26 ft. Lbs (torque) of resistance and reinstalling the Oil Pump.

To replace the Timing Chain and sprockets, one has to remove the Oil Pump and rotate the Crankshaft until the timing marks on the Crankshaft and the camshaft sprockets are aligned without turning the Crankshaft assembly after removing the Timing Chain to avoid damaging the piston assemblies or valves. Then, take out the camshaft sprocket bolts and the camshaft sprocket itself with the Timing Chain. Use j 8433 (Two Jaw Puller), j 41816-2 (Crankshaft End Protector) and j 41558 (Crankshaft Sprocket Remover) to remove the Crankshaft sproket, and if required to remove the Crankshaft sprocket key. Under proper conditions, clean and inspect the Timing Chain and the sprockets. For installation, install the key first into the Crankshaft keyway, tapping it in until both ends are seated. Next, attach the Crankshaft sprocket to the front of the Crankshaft so that the key of the Crankshaft aligns with the keyway of the Crankshaft sprocket and, using the j 41665 (Crankshaft Balancer and Sprocket Installer), seat the sprocket against the Crankshaft flange. Rotate the Crankshaft sprocket to position the alignment mark at the 12 o clock and position, for the camshaft sprocket locating pin to be in correct alignment with the alignment hole, and the sprocket teeth match up with the Timing Chain correctly. Match the camshaft and Crankshaft sprocket marks, placing the camshaft alignment mark at 6:00 before installing camshaft sprocket and Timing Chain. If so, rotate camshaft or Crankshaft sprocket to align the timing marks then install the sprockets of the camshaft bolts tighten them to 35 n.m (26 ft.lbs) and then substitute the Oil Pump.

You need to begin the Timing Chain and sprocket replacement process by removing the Oil Pump followed by the camshaft sprocket bolts and finally the camshaft sprocket and Timing Chain. The j8433 (Pulley Puller) and j41816-2 (Crankshaft End Protector) and j41558 (Crankshaft Sprocket Remover) should be used to remove the Crankshaft sprocket followed by removal of the Crankshaft sprocket key when needed. Check the quality of the Timing Chain while examining its sprockets prior to starting the installation process. The key must be reinstalled into the keyway of the Crankshaft until the ends fully seat. Mount the Crankshaft sprocket onto the Crankshaft front surface through precise key alignment between the parts before using the j41665 to fully connect it against the Crankshaft flange. The rotative motion of the Crankshaft sprocket should position its alignment mark at the 12 o'clock angle while the locating pin of the camshaft sprocket lines up with the camshaft sprocket alignment hole and sprocket teeth properly mesh with the Timing Chain. After aligning the camshaft with the Crankshaft sprocket marks properly you should install the camshaft sprocket with its Timing Chain while making minor adjustments to line up the timing marks. You should install the camshaft sprocket bolts followed by tightening them to 35 nm (26 ft. Lbs.) before reinstalling the Oil Pump.

The procedure for Timing Chain replacement starts with removing the Oil Pump and aligning the Crankshaft and camshaft sprocket timing marks then never rotating the Crankshaft assembly after the chain removal to protect valve and piston assemblies from damage. First remove the camshaft sprocket bolts before proceeding to remove both the camshaft sprocket and Timing Chain. Remove the Crankshaft sprocket by using the j 8433 two jaw puller (J 8433), j 41816-2 Crankshaft end protector (J 41816-2), and j 41558 Crankshaft sprocket remover (J 41558). If the Crankshaft sprocket key is present, you must also remove it. Check and clean the Timing Chain and sprockets before you install them. To reinstall the key, drop it into the Crankshaft keyway slot before pounding it into position until the complete ends are in place. Use the j 41665 Crankshaft balancer and sprocket installer (J 41665) to install the Crankshaft sprocket onto the front of the Crankshaft while maintaining alignment between the Crankshaft key and sprocket keyway. The sprocket must be properly seated against the Crankshaft flange. Position the Crankshaft sprocket alignment mark at the 12 o'clock point so that the locating pin of the camshaft sprocket matches the camshaft alignment hole and the sprocket teeth securely mesh with the Timing Chain. You should place both the camshaft sprocket and Timing Chain in position and make adjustments to either sprocket if needed to match up their timing marks. Screw in the camshaft sprocket bolts and torque them to 35 nm (26 ft. Lbs.).the Oil Pump should be reinstalled at this stage.

Installation of rear pinion bearing race installer (J 5590) and Crankshaft gear remover (J 5825-A) serves as necessary tools for camshaft gear/sprocket service and repair procedures. The first step begins with removing the Crankshaft position (CKP) sensor reluctor ring before inserting a 7/16-20 x 1 inch bolt at the end of the Crankshaft. Use a bolt that is neither the Crankshaft balancer bolt nor longer than 1 inch for safety. Rotating the Crankshaft should stop when the alignment of timing marks appears on the sprockets at the tdc of compression stroke for cylinder number 4. After separating the tensioner shoe from the pin you can remove the sprocket bolts from the camshaft then extract both the Timing Chain and sprocket. The Crankshaft gear remover (J 5825-A) operated with an open-end wrench safely removes the Crankshaft sprocket before proceeding to take out the Crankshaft balancer key. First remove the Timing Chain tensioner bracket bolt and bracket before cleaning all components and inspecting both the Timing Chain and the sprocket parts. Secure the Timing Chain tensioner bracket along with its bolt by torquing it to 12 nm (106 inch lbs.) if bracket installation becomes necessary. Put the key into the Crankshaft keyway then adjust its position between straight and slightly worn and center the keyway of the Crankshaft sprocket with the balancer key. The rear pinion bearing race installer (J 5590) provides the necessary tool for installing the Crankshaft sprocket. Position the camshaft sprocket with its alignment mark facing the 6 o'clock position after the Timing Chain wraps the Crankshaft sprocket and lines up to the left side of the engine. Install the Timing Chain tensioner shoe to its bracket by placing its top under the tab. Then position the camshaft Timing Chain sprocket inside the Timing Chain for alignment according to the camshaft installation marks. Installing the camshaft sprocket requires avoiding hammer usage to defend the expansion cup plug from being removed. Use 25 nm torque when tightening camshaft sprocket bolts while setting the Crankshaft sprocket at 12 o'clock alignment with the camshaft sprocket at 6 o'clock orientation. After removing the Crankshaft bolt you need to reinstall the ckp sensor reluctor ring.

Remove the exhaust camshaft position actuator bolt and the actuator itself.

Begin by removing the engine front cover.

Install the Timing Chain Retention Tool (J 44217) by placing the hook portion into one of the timing chain links near the timing chain shoe on both sides of the engine and tightening the wingnuts, ensuring the hooks remain in place and the gauge blocks are firmly positioned on the edge of the head.

The Timing Belt Alignment Kit (J42069-1 and J42069-2).

Install the key into the crankshaft keyway, ensuring it is tapped in until both ends are seated.

Tighten the CMP actuator solenoid valve first to 65 N.m and then an additional 90 degrees using the J 45059.