Timing chain and sprockets — removal, inspection and installation
1. Position the number one piston at TDC on the compression stroke (see Top Dead Center (TDC) for number one piston — locating ). Confirm the engine is at TDC on the compression stroke by verifying that the timing mark on the crankshaft pulley/vibration damper is aligned with the «0» mark on the timing chain cover and the camshaft sprocket marks are aligned with the marks on the camshaft front bearing caps (see illustration 3.9 and the accompanying illustration).
i. 1 Camshafts and crankshaft TDC timing chain mark locations
1 Intake camshaft sprocket
2 Exhaust camshaft sprockets
3 Intake camshaft sprocket timing mark
4. Exhaust camshaft sprocket timing mark
5 Timing chain «yellow» colored link – intake
6 Timing chain «yellow» colored link — exhaust
7 Index mark, not a timing mark
8 Crankshaft «TDC» keyway at 12 o’clock position
Note: There are two sets of marks on the camshaft sprockets. The marks that align at TDC are for TDC reference only; the other two marks are used to align the sprockets with the timing chain during installation.
2. Remove the crankshaft pulley/vibration damper, being careful not to rotate the engine from TDC (1). If the engine rotates off TDC during this step, reposition the engine back to TDC before proceeding.
3. Remove the drivebelt tensioner and the crankshaft position sensor from the timing chain cover. Also remove the bolt securing the crankshaft position sensor wiring harness to the timing chain cover.
4. Remove the oil pan (3).
5. Remove the timing chain cover mounting fasteners and carefully pry the cover off the engine from several locations.
Note: The timing chain cover has several different size mounting bolts; take note of each bolt’s location so they can be returned to the same locations on reassembly.
6. Once the cover is off, remove the 0-rings from the crankcase.
7. Remove the top chain guide mounting bolt and guide (see illustration).
i. 7 Top chain guide, mounting bolt and locating pin
8. Let the tensioner plunger extend until a 0.06-inch (1.5 mm) pin can be inserted into the alignment holes (see illustration) of the stopper plate and the tensioner. Release the tensioner and make sure the pin is secured.
i. 8 Align the hole on the lock with the hole in the tensioner, then insert a 0.06-inch (1.5 mm) pin or drill bit through both components to lock the tensioner
9. Remove the mounting bolts and the timing chain tensioner.
10. Remove the timing chain tensioner pivot arm/chain guide and the stationary timing chain guide.
11. Lift the timing chain off the camshaft sprockets and remove the timing chain and crankshaft sprocket as an assembly from the engine. The crankshaft sprocket should slip off the crankshaft by hand. If not, carefully pry the sprocket off the crankshaft.
Note: If you intend to reuse the timing chain, use white paint or chalk to make a mark indicating the front of the chain. If a used timing chain is reinstalled with the wear pattern in the opposite direction, noise and increased wear may occur.
12. To remove the camshaft sprockets, loosen the bolts while holding the lug on the camshaft with a wrench (see illustration). Note the identification marks on the camshaft sprockets before removal, then remove the bolts. Pull on the sprockets by hand until they slip off the dowels. If necessary, use a small puller, with the legs inserted in the relief holes, to pull the sprockets off.
i. 12 Hold the lug on the camshaft with a wrench to keep it from rotating as the sprocket bolts are loosened – when loosening the camshaft sprocket, loosen only the center bolt which secures the sprocket to the camshaft
Note: These models are equipped with variable valve timing, which consists of an actuator assembly attached to the camshaft sprocket. When removing the sprocket, only loosen and remove the center bolt, which fastens the sprocket to the camshaft. Do not loosen the outer four bolts that secure the VVT actuator to the sprocket.
Inspection
13. Visually inspect all parts for wear and damage. Check the timing chain for loose pins, cracks, worn rollers and side plates. Check the sprockets for hook-shaped, chipped and broken teeth. Also check the timing chain for stretching and the diameter of the timing sprockets for wear with the chain assembled on the sprockets (see illustrations). Be sure to measure across the chain rollers when checking the sprocket diameter and to measure chain stretch at three or more places around the chain. Maximum chain elongation and minimum sprocket diameter (with chain) should not exceed the amount listed in this Chapter’s Specifications. Replace the timing chain and sprockets as a set if the engine has high mileage or fails inspection.
i. 13a Timing chain stretch is measured by checking the length of the chain between 8 links (15 pins) at 3 or more places (selected
randomly) around the chain — If chain stretch exceeds the specifications between any of the 15 pins, the chain must be replaced
i. 13b Wrap the chain around the crankshaft timing sprocket and measure the diameter of the sprocket across the chain rollers — if the measurement exceeds the minimum sprocket diameter, the chain and the timing sprockets must be replaced
14. Check the chain guides for excessive wear (see illustration). Replace the chain
guides if scoring or wear exceeds the amount listed in this Chapter’s Specifications. Note that some scoring of the timing chain guide shoes is normal. If excessive wear is indicated, it will also be necessary to inspect the chain guide oil hole on the front of the block for clogging.
i. 14 Timing chain guide wear is measured from the top of the chain contact surface to the bottom of the wear grooves
Installation
Caution: Before starting the engine, carefully rotate the crankshaft by hand through at least two full revolutions (use a socket and breaker bar on the crankshaft pulley center bolt). If you feel any resistance, STOP! There is something wrong — most likely, valves are contacting the pistons. You must find the problem before proceeding. Check your work and see if any updated repair information is available.
15. Remove all traces of old sealant from the timing chain cover and the mating surfaces of the engine block and cylinder head.
16. Make sure the camshafts are positioned with the dowel pins at the top in the 12 o’clock position, then install both camshaft sprockets in their original locations by aligning the dowel pin hole on the rear of the sprockets with the dowel pin on the camshaft. Apply medium strength thread locking compound to the camshaft sprocket bolt threads and make sure the washers are in place. Hold the camshaft from turning as described in Step 21 and tighten the bolts to the torque listed in this Chapter’s Specifications. Make sure the camshaft sprocket is fully seated against the camshaft flange (see illustration).
i. 16 Camshaft timing sprocket installation details
17. Temporarily install the crankshaft pulley bolt and rotate the crankshaft until the keyway is pointing to the 10 o’clock position.
18. Rotate the camshafts as necessary to align the TDC marks on the camshaft sprockets (see illustration).
i. 18 Timing chain alignment details
1 Intake camshaft sprocket
2 Exhaust camshaft sprockets
3 Intake camshaft sprocket timing mark
4 Exhaust camshaft sprocket timing mark
5 Timing chain «yellow» colored link — intake
6 Timing chain «yellow» colored link – exhaust
7 Index mark, not a timing mark
8 Timing chain «pink» colored link — crankshaft
9 Crankshaft timing mark
10 Crankshaft keyways 10 o’clock position
11 Crankshaft «TDC» keyway at 12 o’clock position
19. Install the stationary timing chain guide.
20. Loop the timing chain around the exhaust camshaft sprocket. Align the yellow colored link with the exhaust camshaft
sprocket timing mark.
Note: There are three colored links on the timing chain. The pink colored link is the link farthest away from the two yellow colored links that are closest together.
21. Guide the chain into the stationary chain guide and align the crankshaft sprocket with the pink colored link and the mark on the crankshaft sprocket.
Note: Once the timing mark on the crankshaft sprocket and the colored link have been aligned, it may be necessary to tie the chain to the sprocket to prevent it from falling off during installation.
22. Slip the timing chain around the intake camshaft sprocket but not onto the teeth of the sprocket. Using a wrench on the lug on the intake camshaft, rotate the camshaft counterclockwise to align the timing mark on the intake camshaft sprocket and the chain colored link. Once the camshaft sprocket and colored link are aligned, install the chain onto the teeth of the camshaft sprocket.
Caution: Do not let go of the wrench holding the intake camshaft sprocket in place until the tensioner is installed.
23. Using your other hand, remove the string holding the chain to the crankshaft sprocket. Rotate just the crankshaft clockwise until the keyway is pointing to the 12 o’clock position and all the slack is removed.
24. Install the tensioner guide and mounting bolt to the torque listed in this Chapter’s Specifications.
25. Install a new gasket and the tensioner with the mounting bolts. Tighten the tensioner mounting bolts to the torque listed in this Chapter’s Specifications, then remove the pin and allow the plunger to contact the tensioner guide.
26. Confirm that the number one piston is still at TDC on the compression stroke and that the timing marks on the crankshaft and camshaft sprockets are aligned with the colored links on the chain (see illustration 6.18).
27. Install the top chain guide mounting bolt and guide.
28. Apply a bead of RTV sealant to the timing chain cover sealing surfaces. Place the timing chain cover in position on the engine and install the bolts in their original locations.
29. Tighten the bolts and nut evenly in several steps to the torque listed in this Chapter’s Specifications (see illustrations). Be sure to follow the sealant manufacturer’s recommendations for assembly and sealant curing times.
i. 29a Timing chain cover fastener identification (see the Specifications for the torque settings)
Bolts A = 1. 18 inch (30 mm)
Bolts B = 1. 38 inch (35 mm)
Bolts C = 1. 77 inch (45 mm)
Nuts D
i. 29b Timing chain cover fastener tightening sequence (see the Specifications for the torque settings)
30. Install the passenger’s side mounting bracket (see illustration) to the front of the timing chain cover and tighten the bolts in sequence to the torque listed in this Chapter’s Specifications.
i. 30 Passenger’s side mounting bracket bolt identifications
31. Install the crankshaft pulley/vibration damper (1).
Caution: Carefully rotate the crankshaft by hand through at least two full revolutions (use a socket and breaker bar on the crankshaft pulley center bolt). If you feel any resistance, STOP! There is something wrong — most likely, valves are contacting the pistons. You must find the problem before proceeding. Check your work and see if any updated repair information is available.
32. Rotate the engine clockwise at least two revolutions and reposition the number one piston at TDC on the compression stroke (see Top Dead Center (TDC) for number one piston — locating ). Visually confirm that the timing mark on the crankshaft pulley/vibration damper is aligned with the «0» mark on the timing chain cover and the camshaft sprocket marks are aligned and parallel with the top of the timing chain cover as shown in illustrations 6.1.
33. The remainder of installation is the reverse of removal.