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Home >> Chevrolet >> 2006 >> Cobalt LTZ >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 4 (Engine Mechanical - 2.4L) >> Repair Instructions >> Off-Vehicle Repair Instructions >> Timing Chain, Sprockets, Tensioner Installation >> Installation Procedure

Installation Procedure

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    Fig 1: View Of Crankshaft Sprocket Timing Mark
    GM466551Courtesy of GENERAL MOTORS CORP.
  1. Install the timing chain drive sprocket to the crankshaft with the timing mark in the 5 o'clock position.
    2. Fig 2: Identifying Colored Links On Timing Chain
    GM1594347Courtesy of GENERAL MOTORS CORP.
    IMPORTANT:
    • There are three colored links on the timing chain. Two links are of matching color, and one link is of a unique color. Use the following procedure to line up the links with the actuators. Orient the chain so that the colored links are visible.
    • Always use new actuator bolts.
  2. Assemble the intake camshaft actuator into the timing chain with the timing mark lined up with the uniquely colored link (1). Hand tighten a new intake camshaft actuator bolt.
    3. Fig 3: Locating Cylinder Block Bosses
    GM412535Courtesy of GENERAL MOTORS CORP.
  3. Lower the timing chain through the opening in the cylinder head. Use care to ensure that the chain goes around both sides of the cylinder block bosses (1, 2).
    4. Fig 4: Lining Up First Pink Link With Timing Mark On Crankshaft Sprocket
    GM1594349Courtesy of GENERAL MOTORS CORP.
  4. Route the timing chain around the crankshaft sprocket and line up the first matching colored link (2) with the timing mark on the crankshaft sprocket, in approximately the 5 o'clock position.
    5. Fig 5: Identifying Adjustable Timing Chain Guide
    GM1403949Courtesy of GENERAL MOTORS CORP.
    NOTE: Refer to Fastener Notice .
  5. Install the adjustable timing chain guide through the opening in the cylinder head and install the adjustable timing chain bolt.

    Tighten:  Tighten the adjustable timing chain guide bolt to 10 N.m (89 lb in).

    6. Fig 6: Exhaust Cam Bolt And The Exhaust Cam Actuator
    GM1403953Courtesy of GENERAL MOTORS CORP.
    IMPORTANT: Always install NEW actuator bolts.
  6. Install the exhaust camshaft actuator and a NEW bolt loosely onto the exhaust camshaft.
    7. Fig 7: Aligning Timing Mark On Actuator With Last Pink Colored Link
    GM1594351Courtesy of GENERAL MOTORS CORP.
  7. Align the timing mark on the actuator with the last matching colored link (3). Install the bolt finger tight.
    8. Fig 8: Identifying Cam Actuator, Camshaft & Chain
    GM1403887Courtesy of GENERAL MOTORS CORP.
    NOTE: Do not rotate either camshaft more than half turn in either direction with crankshaft at top dead center (TDC). To do so may cause valve to piston contact resulting in a damaged valve and/or a damaged piston.
  8. If the camshaft is 180 degrees out of time, use the following procedure to re-align the cam.

    Using a 24 mm wrench, first turn the intake camshaft until the alignment feature on the back of the camshaft actuator seats in the notch in the front of the intake camshaft.

    1. Turn the crankshaft 45 degrees in either direction.
    2. Turn the intake cam to the appropriate location.
    3. Turn the crankshaft back to top dead center.
  9. When the actuator seats on the cam, tighten the sprocket bolt hand tight.
  10. Verify that all of the colored links and the appropriate timing marks are still aligned. If they are not, repeat the portion of the procedure necessary to align the timing marks.
    11. Fig 9: View Of Fixed Timing Chain Guide
    GM412165Courtesy of GENERAL MOTORS CORP.
  11. Install the fixed timing chain guide and bolts.

    Tighten:  Tighten the fixed timing chain guide bolts to 15 N.m (11 lb ft).

    12. Fig 10: Upper Timing Chain Guide
    GM1403955Courtesy of GENERAL MOTORS CORP.
  12. Install the upper timing chain guide and bolts.

    Tighten:  Tighten the upper timing chain guide bolts to 10 N.m (89 lb in).

    13. Fig 11: Tightening Camshaft Actuator Bolt
    GM1403882Courtesy of GENERAL MOTORS CORP.
  13. Using a 24 mm wrench, engage the hex on the intake camshaft and using a torque wrench, tighten the camshaft actuator bolt.

    Tighten:  Tighten the intake camshaft position actuator bolt to 30 N.m (22 lb ft), plus 100 degrees using the J 45059  .

  14. Using a 24 mm wrench, engage the hex on the exhaust camshaft and using a torque wrench, tighten the camshaft actuator bolt.

    Tighten:  Tighten the exhaust camshaft position actuator bolt to 30 N.m (22 lb ft), plus 100 degrees using the J 45059  .

    15. Fig 12: Measuring Timing Chain Tensioner Assembly
    GM714496Courtesy of GENERAL MOTORS CORP.
  15. Inspect the timing chain tensioner. If the timing chain tensioner, O-ring seal, or washer is damaged, replace the timing chain tensioner.
  16. Measure the timing chain tensioner assembly from end to end.

    A new tensioner should be supplied in the fully compressed non-active state. A tensioner in the compressed state will measure 72 mm (2.83 in) (a) from end to end. A tensioner in the active state will measure 85 mm (3.35 in) (a) from end to end.

    17. Fig 13: Compressing Timing Chain Tensioner
    GM797246Courtesy of GENERAL MOTORS CORP.
  17. If the timing chain tensioner is not in the compressed state, perform the following steps:
    1. Remove the piston assembly from the body of the timing chain tensioner by pulling it out.
    2. Install the J 45027-2 (2) into a vise.
    3. Install the notch end of the piston assembly into the J 45027-2 (2).
    4. Using the J 45027-1 (1), turn the ratchet cylinder into the piston.
    18. Fig 14: Measuring Timing Chain Tensioner Assembly
    GM714496Courtesy of GENERAL MOTORS CORP.
  18. Inspect the bore of the tensioner body for dirt, debris, and damage. If any damage appears, replace the tensioner. Clean dirt or debris out with a lint free cloth.
  19. Install the compressed piston assembly back into the timing chain tensioner body until it stops at the bottom of the bore. Do not compress the piston assembly against the bottom of the bore. If the piston assembly is compressed against the bottom of the bore, it will activate the tensioner, which will then need to be reset again.
  20. At this point the tensioner should measure approximately 72 mm (2.83 in) (a) from end to end. If the tensioner does not read 72 mm (2.83 in) (a) from end to end repeat steps  1 and  4.
    21. Fig 15: Identifying Timing Chain Tensioner
    GM412158Courtesy of GENERAL MOTORS CORP.
  21. Inspect to ensure all dirt and debris is removed from the timing chain tensioner threaded hole in the cylinder head.
  22. Install the new timing chain tensioner assembly.

    Tighten:  Tighten the timing chain tensioner to 75 N.m (55 lb ft).

  23. The timing chain tensioner is released by compressing it 2 mm (0.079 in) which will release the locking mechanism in the ratchet. To release the timing chain tensioner, use a suitable tool with a rubber tip on the end. Feed the tool down through the cam drive chest to rest on the cam chain. Then give a sharp jolt diagonally downwards to release the tensioner.
    24. Fig 16: View Of Oil Nozzle & Bolt
    GM412200Courtesy of GENERAL MOTORS CORP.
  24. Install the timing chain oiling nozzle.

    Tighten:  Tighten the timing chain oiling nozzle bolt to 10 N.m (89 lb in).

    25. Fig 17: View Of Fixed Timing Chain Guide Access Plug
    GM412164Courtesy of GENERAL MOTORS CORP.
  25. Apply sealant GM P/N 12378521 (Canadian P/N 88901148) compound to the thread, and install the timing chain guide bolt access hole plug.

    Tighten:  Tighten the access hole plug to 90 N.m (66 lb ft).

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