Timing Chain & Sprockets (Crankshaft): Installation

1. Ensure crankshaft keyway is aligned with timing mark on block. See Figure. Install crankshaft sprocket. Tighten to specification. See TORQUE SPECIFICATIONS . Apply engine oil to idler sprocket bushing. Install crankshaft timing chain on idler sprocket, aligning Dark Blue link of timing chain with timing chain alignment mark on idler sprocket. See Fig 1.
2. Install crankshaft timing chain to crankshaft sprocket, aligning Yellow link of timing chain with timing mark on crankshaft sprocket. See Fig 2. Apply engine oil to idler sprocket bushing, and install idler sprocket. Install timing chain guides. Depress crankshaft timing chain tensioner plunger and hold in place with paper clip or similar retainer. Install tensioner, and tighten bolts to specification. See TORQUE SPECIFICATIONS . Remove tensioner plunger retainer.
3. Ensure crankshaft keyway is aligned with timing mark on block, and Yellow link on crankshaft timing chain is aligned with crankshaft timing mark. Ensure Dark Blue link of crankshaft timing chain is aligned with timing mark on idler sprocket. Install camshaft timing sprockets and chain. Install camshaft sprocket bolts and tighten to specification. See TORQUE SPECIFICATIONS .
4. Depress camshaft timing chain tensioner plunger into tensioner body. Insert paper clip or similar retainer through hole in tensioner body to keep plunger in place. Install tensioner and tighten to specification. See TORQUE SPECIFICATIONS . Remove plunger retainer from tensioner.
5. Turn crankshaft 2 revolutions realigning keyway with timing mark on block. Ensure guide pins on camshafts are in line with notches on cylinder head. Apply engine oil to timing chains, tensioner, guides, and sprockets. To complete installation, reverse removal procedure. Tighten bolts and nuts to specification. See TORQUE SPECIFICATIONS . On 4WD models, adjust front wheel toe-in. See appropriate SPECIFICATIONS & PROCEDURES article in WHEEL ALIGNMENT.

Fig 1: Aligning Crankshaft Timing Chain & Idler Sprocket

Courtesy of GENERAL MOTORS CORP.

Fig 2: Aligning Crankshaft Timing Chain & Crankshaft Sprocket

Courtesy of GENERAL MOTORS CORP.