Timing Chain: Service and Repair

TIMING CHAIN

(Engine Removed)

Remove upper and lower timing case covers. Service and Repair





CAUTION:
- Special BMW service tools are needed for this procedure.
- Read the procedure through before beginning the job. If the camshafts are not property timed, the pistons can contact the valves.


- Remove radiator cooling fan.

NOTE: The radiator cooling fan nut (32 mm wrench) has left-hand threads.

- Remove spark plugs.

- Remove cylinder head covers from left and right cylinder heads. Service and Repair




- Unbolt oil pipes from both cylinder heads.

- Remove timing chain tensioner from side of right timing chain cover. Install in its place BMW special tool no.11 3 390. Thread special tool in until no slack is present in chain, tightening to 1.3 Nm (12 in-lb).

NOTE:
- BMW special tool no.11 3 390 is a dummy primary chain tensioner and simulates the function of the hydraulic tensioner.
- Assume left/right orientation sitting in driver seat.




- Set cylinder no.1 to TDC by rotating engine in normal operating direction.
- Arrows on intake camshaft sprockets point up.
- Camshaft lobes at cylinder no.1 face in.



- 0/T mark on vibration damper aligns with pointer on front timing chain cover.

- Loosen 3 accessible bolts on camshaft sprockets at left and right cylinder heads.

NOTE: Hold the camshaft stationary (at hex on camshaft) when loosening or tightening the camshaft sprocket mounting bolts.

- Turn engine over one complete revolution. Loosen remaining bolts on camshaft sprockets.




- Turn engine over to TDC and lock crankshaft at TDC using BMW special tool no.11 2 300 (arrow).

- Lock camshafts at TDC using BMW special tools 11 2 442/446 (cyl. 5-8) and tools 11 2 445/441 (cyl. 1-4). Install camshaft tools with letter A on exhaust side and letter E on intake side.
- Using hex casting on camshafts, turn camshafts slightly from side to side to ensure proper fit of camshaft locking tools.

CAUTION: The camshafts must be locked in the TDC position using BMW special tools at the rear of the camshafts. The arrows on the sprockets should not be used to set the engine at TDC.

- Tighten top three camshaft sprocket bolts.

- Remove crankshaft and camshaft locking tools. Turn engine over in normal operating direction one complete revolution. Tighten remaining sprocket mounting bolts using sequence and torques listed earlier.

- Remove dummy chain tensioner and install chain tensioner.

- The remainder of installation is reverse of removal.