15. Timing Chain, Sprockets, Guides, and Tensioner Installation

Camshaft Timing Chain, Sprocket, and Tensioner (DOHC)

Assemble the timing chain, the sprockets, the guides and the tensioners:






1. Verify that the crankshaft is positioned at 90 degrees past top dead center (TDC). The crankshaft keyway and sprocket must be aligned with the cylinder block main bearing cap split line, as viewed from the accessory drive end, to prevent piston and valve damage.





Notice: Do not torque the camshaft retaining bolts against the 3/16 in. timing pins as it will damage the cylinder head.

2. Install the camshaft timing gears, the retaining bolts and washers. The letters FRT on the sprockets must face forward, away from the cylinder head. Wrench flats 24 mm are provided to hold the camshafts from rotating while torquing the bolts.

Tighten
Tighten the camshaft sprockets-to-camshafts to 100 N.m (74 lb ft).






3. Bring the camshafts up to the number one TDC by rotating the camshaft and sprocket until the timing pins 4.77 mm (3/16 in) drill can be installed. Wrench flats are installed on the camshafts to assist with rotation.






4. Rotate the crankshaft counterclockwise, as viewed from the accessory drive end, until the number one cylinder is TDC. The crankshaft sprocket timing mark will align with cylinder block timing mark.






Caution: The camshaft can rotate during timing chain installation when the timing pins (4.77 mm (3/16 in) drill) have not been installed. Do not place fingers between the camshaft sprockets and the chain during the timing chain installation.

5. Place the timing chain over the camshaft sprockets and under the crankshaft sprocket.






Notice: Excess slack in the chain must be kept to the chain tensioner side (movable guide) of the cylinder block when installing the timing chain or the camshaft sprockets will not be correctly timed to the crankshaft sprocket.

Important: Two separated black link plates align the pip marks on the camshaft sprockets and another 2 paired link plates align the crankshaft sprocket tooth that is located at the six o'clock position. The pip mark on the crankshaft sprocket must be aligned with the timing mark on the cylinder block.

Important: Alignment of both timing pin holes, crankshaft sprocket pip mark with cylinder block mark, black links with camshaft and crankshaft sprockets must be correct to make sure the engine is properly timed.

6. Ensure that the black colored link plates are located over the pip mark on the cam sprockets only. The crankshaft sprocket tooth must be pointed directly downward at the 6 o'clock position between the 2 silver colored links. The pip mark on the crankshaft sprocket will be aligned with the timing mark on the cylinder block.






Important: The timing chain should be snug against the fixed guide.

7. Install the fixed guide.

Tighten
Tighten the timing chain fixed guide-to-block to 26 N.m (19 lb ft).






8. Install the pivoting chain guide. Inspect for clearance between the block and the head. Torque the bolt and ensure the guide pivots freely.

Tighten
Tighten the timing chain pivot guide-to-head to 26 N.m (19 lb ft).

Important: The camshafts must be positioned fully forward prior to bearing cap installation.

9. Install the 2 forward remaining camshaft bearing caps and timing chain guide.

Tighten
Tighten the camshaft bearing cap-to-head (LL0) to 14 N.m (10 lbs ft).






10. Retract the tensioner plunger and pin the ratchet lever using a 3.18 mm (1/8 in) or No 31 drill. Install the chain tension and torque the 2 bols. Remove the drill and allow the tensioner plunger to extend.

Tighten
Tighten the timing chain tensioner-to-block to 19 N.m (14 lb ft).

11. Verify all timing marks for accuracy. Remove the camshaft timing pins.