See Figure 1
REMOVAL & INSTALLATION
Except 325 Series, 524td, 528e, M3, M5 and M6 Models
- Remove the oil line from the top of the cylinder head.
Observe the location of the seals when removing the hollow oil line studs. Install new seals in the same position.
- Remove the cylinder head. Support the head in such a way that the valves can be opened during camshaft removal.
- Adjust the valve clearance to the maximum clearance on all rocker arms.
- Remove the fuel pump and pushrod on carbureted engines.
- On 4-cylinder engines: Special tools are used to hold the rocker arms away from the camshaft lobes. On the 320i, use tool 11 1 040; on the 318i, use 11 0 040. Use these numbers to shop for tools from independent sources also.
The proper tool or its equivalent, must be used on fuel injection engines to avoid distorting the valve heads.
- On the 320i and 318i, the clamping bolt for the special tool is off-center. The clamp must be mounted so the shorter end faces the exhaust side of the engine, or the valve heads may contact each other. On the 318i, install 2 dowel pins in the head.
- On 6-cylinder engines: A special tool set (11 1 060 and 00 1 490) or its equivalent, is used to hold the rocker arms away from the camshaft lobes. When installing the tool, move the intake rocker arms of No. 2 and 4 cylinders forward approximately 0.25 inches (0.01mm) and tighten the intake side nuts to avoid contact between the valve heads. On 6-cylinder engines, turn the camshaft 15° clockwise to install the tool. On these engines, to avoid contact between the valve heads, first tighten the tool mounting nuts on the exhaust side to the stop and then tighten the intake side nuts slightly. Reverse this exactly during removal.
To remove the camshaft on 4-cylinder engines:
- Turn the camshaft until the flange is aligned with the cylinder head boss. Remove the guide plate retaining bolts and move the plate downward and out of the slots on the rocker arm shafts.
- Carefully remove the camshaft from the cylinder head.
- Remove the 2 plugs behind the guide plate (at top), coat with Loctite® No. 270® or equivalent, and replace them.
To remove the camshaft on 6-cylinder engines:
- Rotate the camshaft so that the 2 cutout areas of the camshaft flange are horizontal and remove the retaining plate bolts.
- Carefully remove the camshaft from the cylinder head.
- The flange and guide plate can be removed from the camshaft by removing the lockplate and nut from the camshaft end.
Install the camshaft and associated components in the reverse order of removal, but observe the following:
- After installing the camshaft guide plate, the camshaft should turn easily. Measure and correct the camshaft end-play.
- The camshaft flange must be properly aligned with the cylinder head before the sprocket is installed. Refer to the disassembly procedure.
- Install the oil tube hollow stud washer seals properly, one above and one below the oil pipe. On 6-cylinder engines, the arrow on the oil line must face forward.
- Install the cylinder head. Adjust the valves.
To complete this procedure, it is necessary to have several special tools to install a new oil seal. Use BMW tools 11 2 212, 11 3 080, and 00 5 500.
- Remove the cam cover and vacuum pump.
- Remove the exhaust side rocker arm of cylinder No. 2 and the intake rocker arm of cylinder No. 3. It is not necessary to disturb the rocker pedestals; keep the rockers in order of reinstallation in the same positions.
- Turn the crankshaft until it is at TDC with No. 6 cylinder's valves in the overlap position.
- Remove the front cover.
- Remove the timing belt. Make sure to loosen the camshaft sprocket bolt before releasing belt tension and removing the belt.
- Once the belt is removed, remove the bolt and washer and remove the camshaft sprocket.
- Disconnect the oil line that is in the way. Then, remove the camshaft bearing cap bolts and remove the caps, keeping them in order. Remove the oil seal from the front bearing cap. Remove the camshaft.
- If replacing the camshaft, replace all the rocker arms as described above. Also, transfer the steels ring that drives the vacuum pump to the new camshaft.
- Oil all bearing surfaces with clean engine oil and install the camshaft. Install the caps and bolts, and tighten grade M6 bolts to 6-7 ft. lbs. (8-9 Nm), grade M8 bolts should be tighten to 15-17 ft. lbs. (19-22 Nm). The front bearing cap lower surface must be coated with a brush-on universal sealing compound or equivalent.
- Install a seal installer 11 2 212 or equivalent onto the end of the camshaft. Lubricate the lip of the seal with clean engine oil. Then, press the seal into the bore of the bearing, using a suitable seal installer part no. 11 3 080 and 00 5 500 or equivalent. The seal must be pressed in until it hits the stop.
- Install the oil line. Check the end-play of the camshaft with a dial indicator and compare with specifications. If end-play is excessive with a new camshaft, it may be necessary to replace the cylinder head and bearing caps.
- Install the camshaft sprocket making sure the pin in the camshaft flange fits through the bore in the sprocket and washer. Tighten the bolt to 47-51 ft. lbs. (61-66 Nm).
- Install the timing belt and tension. Reverse the remaining removal procedures.
The cylinder head and the rocker arm shafts must be removed before the camshaft can be removed.
- Remove the cylinder head.
- Mount the cylinder head on a stand. Secure the head to the stand with one head bolt.
- Remove the camshaft sprocket bolt and remove the camshaft distributor adapter and sprocket. Reinstall the distributor adapter on the camshaft.
- Adjust the valve clearance to the maximum allowable on all valves.
- Remove the front and rear rocker shaft plugs and lift out the thrust plate.
- Remove the clips from the rocker arms by lifting them off.
Remove the exhaust side rocker arm shaft:
- Set the No. 6 cylinder rocker arm to the valve overlap position (both rocker arms parallel).
- Push in on the rocker arm on the front cylinder and turn the camshaft in the direction of the intake rocker shaft, using a 1 / 2 inch breaker bar and a deep well socket to fit over the camshaft adapter. Rotate the camshaft until all of the rocker arms are relaxed.
- Remove the rocker arm shaft.
Remove the intake side rocker arm shaft:
- Turn the camshaft in the direction of the exhaust valves.
- Use a deep well socket and 1 / 2 inch breaker bar on the camshaft adapter to turn the camshaft until all of the rocker arms are relaxed.
- Pull out the rocker arm shaft.
- Remove the camshaft thrust bearing cover. Check the radial oil seal and round cord seal and replace them if needed.
- Pull out the camshaft.
Installation is the reverse of removal. Installation notes:
- Use BMW tool 11 2 212 or equivalent over the end of the camshaft during installation of the thrust bearing cover; this will protect the oil seals and guide the cover on.
- The rocker arm thrust plate must be fit into the grooves in the rocker shafts.
- The straight side of the springclip must be installed in the groove of the rocker arm shafts.
- The large oil bores in the rocker shafts must be installed down to the valve guides and the small oil bores must face inward toward the center of the head.
- Adjust the valve clearance.
Note that to perform this operation it is necessary to have an expensive jig, special tool No. 11 3 010 or equivalent. This is necessary to permit safe removal of the camshaft bearing caps and then safe release of the tension the valve springs put on the camshafts. The job also requires an adapter to keep the camshaft sprockets from turning while loosening and tightening their mounting bolts.
- Remove the cylinder head cover. Remove the fan cowl and the fan.
- Remove the mounting bolts and remove the distributor cap. Remove the mounting screws and remove the rotor. Unscrew the distributor adapter and the protective cover underneath. Inspect the O-ring that runs around the protective cover and replace it, if necessary.
- Remove the 2 bolts and remove the protective cover from in front of the right side (intake) camshaft. Remove the bolts and remove the distributor housing from in front of the left (exhaust) side cam. Inspect the O-rings, and replace them if necessary.
- Remove the mounting bolts from the cover at the rear end of the cylinder head and remove it. Replace the gasket. Note that on the M3, 2 of these bolts are longer. These fit into the 2 holes that are sleeved.
- Remove the 2 nuts, located at the front of the head, which mount the upper timing chain guide rail. Then, remove the upper guide rail.
- Turn the crankshaft to set the engine at No. 1 TDC. On the 6-cylinder engine, valves for No. 6 will be at overlap position: both valves just slightly open with timing marks at TDC. On the 4-cylinder engine, valves for No. 4 cylinder will be at overlap position: both valves just slightly open with timing marks, of course, at TDC.
- Remove the cap for the timing chain tensioner, located on the right side of the front timing cover. Then, slide off the damper housing. Remove the seal, discard it, and supply a new one for reassembly.
- Remove the plug, and then release spring tension. Remove the spring and then the piston. Check the length of the spring. It must be 6.18-6.22 inches (158.5-159.5mm) in length; otherwise, replace it to maintain stable timing chain tension.
The timing chain should remain engaged with the crankshaft sprocket while removing the camshafts. Otherwise, it will be necessary to do additional work to restore proper timing. Devise a way to keep the timing chain under slight tension by supporting it at the top while removing the camshaft sprockets in the next step.
- Pry open the lockplates for the camshaft sprocket mounting bolts. Install an adapter to hold the sprockets still and remove the mounting bolts.
- Using an adapter to keep the sprockets from turning and putting tension on the timing chain, loosen and remove the sprocket mounting bolts, keeping the chain supported.
- Mount the special jig on the timing case (which mounts to the top of the head). Then, tighten the jig's shaft to the stop. This will hold both camshafts down against their lower bearings. On the 4-cylinder engine, mark the camshafts as to which side they are on; intake on the driver's side and exhaust on the passenger's side. Also, mark the camshafts as to which end faces forward.
- Remove the mounting bolts and remove the camshaft bearing caps. It is possible to save time by keeping the caps in order, although they are marked for installation in the same positions.
- Once all bearing caps are removed, slowly crank backwards on the jig shaft to gradually release the tension on the camshafts. Once all tension is released, remove the camshafts.
- Carefully remove the camshafts in such a way as to avoid nicking any bearing surfaces or cams.
- Oil all bearing and cam surfaces with clean engine oil. Carefully install the camshafts (marked E for intake and A for exhaust) so as to avoid nicking any wear surfaces. The camshafts should be turned so that the groove between the front cam and sprocket mounting flange faces straight up. Install the special jig and tighten down on the shaft to seat the camshafts.
- Install all bearing caps in order (or as marked). Tighten the attaching bolts to 15-17 ft. lbs. (19-22 Nm). Then, release the tension provided by the jig by turning the bolt and remove the jig.
- Install the intake sprocket (marked E), install the lockplate, and install the mounting bolts. Use the adapter to keep the sprocket from turning, and tighten the bolts to 6-7 ft. lbs. (8-9 Nm). Do the same for the exhaust side sprocket. Make sure the timing chain stays in time.
- Now, slide the timing chain tensioner piston into the opening in the cylinder in the block. Install the spring with the conically wound end facing the plug (or outward). Install the plug into the end of the sprocket and then install it over the spring and use the socket wrench to depress the spring until the plug's threads engage with those in the block. Start the threads in carefully and then tighten the plug to 27-31 ft. lbs. (35-40 Nm). Install a new seal, connector, damper housing, and the outside cap with a new cap seal. Tighten the outside cap to 16-20 ft. lbs. (21-26 Nm) on the engine used in the M5 and M6 and 29 ft. lbs. (38 Nm) on the M3 engine.
- Crank the engine forward just one turn in normal direction of rotation. Now, one camshaft groove on each side should face toward the center of the head and one on each side should face the case boss on the front bearing cap. Lock the sprocket mounting bolts with the tabs on the lockplates.
- Reverse the remaining removal procedures to complete the installation. Before final tightening of the mounting nuts for the guide rail for the top of the timing chain, go back and forth, measuring the clearance between the sprockets and the center of the guide rail to center it. Then, tighten the mounting nuts.
On engines with an aluminum or nylon camshaft sprocket, prying against the sprocket, with the valve train load on the camshaft, can break or damage the sprocket. Therefore, the rocker arm adjusting nuts must be backed off, or the rocker arm and shaft assembly must be loosened sufficiently to free the camshaft. After checking the camshaft end-play, check the valve clearance and adjust if required. Refer to the procedure in Engine Performance and Tune-Up .
- Push the camshaft toward the rear of the engine. Install a dial indicator so that the indicator point is on the camshaft sprocket attaching screw.
- Zero the dial indicator. Position a prybar between the camshaft gear and the engine. Pull the camshaft forward and release it. Compare the dial indicator reading with the specifications.
- If the end-play is excessive, check the spacer for correct installation before it is removed. If the spacer is correctly installed, replace the thrust plate.
- Remove the dial indicator.