Timing Components: Service and Repair
CAMSHAFT SPROCKETS AND TIMING PROCEDUREREMOVAL
CAUTION: The 3.5L is NOT a freewheeling engine. Therefore, care should be taken not to rotate the camshafts or crankshaft with the timing belt removed.
1. Drain cooling system.
2. Remove radiator.
3. Remove refrigerant from air conditioning system using a refrigerant recovery machine. Remove air conditioning condenser.
4. Remove accessory drive belts.
5. Remove crankshaft damper.
6. Remove timing belt covers.
7. Remove timing belt.
CAUTION: When camshaft sprocket bolts are loosened or removed, the camshafts must be re-timed to the engine. Also, the camshaft sprocket bolts must NOT be reused. Refer to camshaft timing and timing belt installation procedure outlined in this section.
8. Hold camshaft sprocket with 36 mm (1-7/16 in.) box wrench and loosen and remove bolt and washer.
NOTE: Do not reuse camshaft sprocket bolt.
9. Remove camshaft sprocket from camshaft. Each sprocket has a "D" shaped hole that allows it to rotate several degrees in each direction on its shaft. This design must be timed with the engine to ensure proper performance of the engine.
INSTALLATION
CAUTION: The camshaft sprockets are not interchangeable from side to side (Fig. 135).
1. Place crankshaft sprocket to the TDC mark on the oil pump housing (Fig. 136).
2. Install a dial indicator in number 1 cylinder to check TDC of the piston (Fig. 141). Rotate the crankshaft until the piston is at exactly TDC. This is important for good engine performance.
3. Install the camshaft alignment Special Tools 6642 to the rear of each cylinder head (Fig. 137).
4. When tensioner is removed from the engine it is necessary to compress the plunger into the tensioner body.
CAUTION: Compress the tensioner slowly, as damage to tensioner could result.
5. Place the tensioner into a vise and SLOWLY compress the plunger into the tensioner (Fig. 138). Total bleed down of tensioner should take about 5 minutes.
NOTE: Index the tensioner in the vise the same way it is installed on the engine. This is to ensure proper pin orientation when tensioner is installed on the engine.
6. Install pin through the tensioner body and plunger to retain plunger in place until tensioner is installed.
NOTE: When the tensioner is removed from the engine, always store with the plunger pointing upward.
7. Install camshaft sprockets onto the camshafts. Install NEW sprocket attaching bolts into place. The 255 mm (10 in.) bolt is to be installed in the left camshaft and the 213 mm (8-3/8 in.) bolt is to be installed into the right camshaft. Do not tighten the bolts. Camshaft sprocket mark should be positioned between the marks on the inner cover (Fig. 139).
8. Install the timing belt starting at the crankshaft sprocket going in a counterclockwise direction (Fig. 140). Install the belt around the last sprocket. Maintain tension on the belt as it is positioned around the tensioner pulley. Each camshaft sprocket mark should still fall between the cover marks.
9. Holding the tensioner pulley against the belt, install the tensioner into the housing and tighten to 28 Nm (250 in. lbs.).
10. When tensioner is in place pull retaining pin to allow the tensioner to extend to the pulley bracket.
11. With number 1 piston at TDC (Fig. 141), hold the camshaft sprocket hex with a 36 mm (1-7/16 in.) wrench and tighten the camshaft bolts to 102 Nm (75 ft. lbs.) plus a 90 degree turn for the Right side and 115 Nm (85 ft. lbs.) plus a 90 degree turn for the left side.
12. Remove dial indicator and install spark plug. Tighten spark plug to 28 Nm (20 ft. lbs.).
13. Remove camshaft alignment special tools 6642 and install cam covers and O-rings. Tighten fasteners to 28 Nm (250 in. lbs.).
14. Install timing belt covers.
15. Install crankshaft damper (Fig. 142).
16. Install accessory drive belts.
17. Install air conditioning condenser, radiator, and radiator fan module.
18. Evacuate and charge air conditioning system.
19. Fill cooling system.
20. Start engine and allow to idle for approximately 1 minute. Then, preferably using a DRBIII, operate engine at speed of 1600 - 2000 RPM for 10 minutes. This will help to bleed out any possible air in the timing belt tensioner.
NOTE: If air ingestion has occurred, the timing belt tensioner will be soft and may generate noise. This noise should disappear, after no more than 15 minutes of engine running time.