Removal & Installation
- Disconnect the negative battery cable. Remove the vibration damper and hub assembly.
- For M50/M52/S50 engines, remove the upper and lower timing case covers. Compress and lock the upper timing chain tensioner. Unbolt the upper timing chain sprockets and remove from the camshafts along with the chain.
- Unscrew the upper chain guide and top bolt on the right chain guide.
- Remove the timing chain sprockets and the lift out the chain. Remove the timing chain guide.
- Remove the tensioning rail, if necessary. Remove the crankshaft sprocket with the proper tool and lift out the Woodruff key.
Remove the reversing roller, if needed.
NOTEThe reversing roller can only be replaced complete with bearings.
- Install the Woodruff key into the channel in the crankshaft. Slide the crankshaft sprocket over the end of the crankshaft with the Woodruff key aligning with the channel in the crankshaft. Use the central mounting bolt to draw the sprocket entirely into position.
- The remaining components are installed in the reverse order from which they were removed. Make sure to tighten the camshaft sprocket bolts to 16 ft. lbs. (22 Nm), the lower timing cover bolts to 6.5-8.0 ft. lbs. (9-11 Nm) for M6 bolts and 16 ft. lbs. (22 Nm) for M8 bolts, the vibration damper hub bolt to 295 ft. lbs. (410 Nm) and the vibration damper bolts to 17 ft. lbs. (23 Nm). Use sealer at the intersections of the timing cover and the pan.
- Connect the negative battery cable, start the engine and check for leaks.
- Disconnect the negative battery cable.
- Remove the upper and lower timing chain covers. The timing chain tensioner has to come off with the cover.
- Turn the engine in the direction of rotation and set cylinder number 1 to TDC. The arrows on the sprockets should face up in the cylinder axis. Use a crankshaft holder to keep the TDC position.
- Loosen and remove the camshaft sprocket bolts from both banks of cylinders. Compress the hydraulic tensioning element to loosen the timing chain. Lock the element with special tool 11-3-420, and remove the sprockets with the chain. Do not rotate the engine with the timing chain removed.
- Guide the chain out of the tensioner rails and off the lower sprocket.
To remove the guide rail:
- On the left side (cylinder bank 1-4), remove the lower mounting bolt and remove the tensioning rail. Pull off the spacer with oil supply for the tensioning rail.
- On the left side, remove the two mounting bolts for the guide rail. Do not mix up the two bolts, it is important to install the same bolt in the same hole. Remove the sliding rail.
- On the right side (cylinder bank 5-8), remove the two mounting bolts on the tensioning rail, and the two bolts on the guide rail. Remove the rails.
- On the right cylinder bank, position the guide rail and install the mounting bolts. Position the tensioning rail, and install the mounting bolts.
- On the left cylinder bank, check the seal for the spacer. Position the guide rail, and install the mounting bolts in the correct holes. Install the spacer. Position the tensioning rail, and install the lower mounting bolt.
- Inspect the sprockets for wear and replace if necessary.
- Install the chain in position.
- Be sure No. 1 piston remains at the top of its firing stroke and the key on the crankshaft is in the 12 o'clock position.
- Position the chain on the guide rail and swing the chain inward and to the left.
- Engage the chain on the crankshaft gear and install the camshaft sprockets into the chain.
- The sprocket on the intake camshaft for cylinder bank 1-4 has a sender pin. With the arrow pointing up, align the pin in the middle of the slots. Install the camshaft sprockets. Remove special tool 11-3-420. Remove the crankshaft holder.
- Install the chain tensioner piston, spring and cap plug, but do not tighten.
- To bleed the chain tensioner, fill the oil pocket, located on the upper timing housing cover, with engine oil and move the tensioner back and forth with a suitable prybar until oil is expelled at the cap plug. Tighten the cap plug securely.
- Install the timing chain covers. Torque the 6mm bolts to 7 ft. lbs. (10 Nm), the 8mm bolts to 16 ft. lbs. (22 Nm), and the 10mm bolts to 35 ft. lbs. (47 Nm).
Connect negative battery cable.