Check the rocker shafts for scoring and wear at the rocker arm pivot points. Check the shaft oiling holes for clogging and varnish. Check the bushing in the rocker arm for wear. Check the adjuster eccentric for flatspots. Check the iron pad for wear and looseness. If the iron pad is loose, it will make a ticking or tapping noise when the engine is running.
REMOVAL & INSTALLATION
Except 325, 325e, 325i, 325iS, 325iX, 524td, and 528e
See Figures 1 and 2
- Remove the cylinder head cover.
- Remove the cylinder head from the engine as outlined in this section. Place on a clean secure work surface
- Remove the camshaft as outlined in this section.
- On 6-cylinder engines, remove the retaining bolts and remove the end cover from the rear of the cylinder head. Slide the thrust rings and rocker arms rearward and remove the circlips from the rocker arm shafts.
On 4-cylinder engines:
- Remove the distributor flange from the rear of the cylinder head.
- Using a long punch, drive the rocker arm shaft from the rear toward the front of the cylinder head.
- Be sure all circlips are off the shaft before attempting to drive the shaft from the cylinder head.
- The intake rocker shaft is not plugged at the rear, while the exhaust rocker shaft must be plugged. Renew the plug if necessary, during the installation.
On 6-cylinder engines:
- Install dowel pins BMW part No. 11 1 063 or equivalent to keep the rocker shafts from turning. Then, remove the rocker shaft retaining plugs from the front of the cylinder head. These require a hex head wrench. Then, back the rocker arms against the spring pressure and remove the circlips retaining the shafts. Remove the dowel pins. If the rocker shafts have welded plugs, the shafts will have to be pressed out of the head with a tool such as 11 3 050 or equivalent.
- Install a threaded slide hammer into the ends of the rear rocker shafts and remove.
- The rocker arms, springs, washers, thrust rings and shafts should be examined and worn parts replaced. Special attention should be given to the rocker arm cam followers. If these are loose, replace the arm assembly. The valves can be removed, repaired or replaced, as necessary, while the shafts and rocker arms are out of the cylinder head.
Install noting the following procedures:
- Design changes of the rocker arms and shafts have occurred with the installation of a bushing in the rocker arm and the use of 2 horizontal oil flow holes drilled into the rocker shaft for improved oil supply. Do not mix the previously designed parts with the later design.
- When installing the rocker arms and components to the rocker shafts, install locating pins in the cylinder head bolt bores to properly align the rocker arm shafts. Note that on 6-cylinder engines, the longer rocker shafts go on the chain end of the engine. The openings face the bores for the cylinder head bolts. The plug threads face outward. The order of installation is: spring, washer, rocker arm, thrust washer, circlip. Note also that newer, short springs may be used with the older design.
- Install sealer on the rocker arm shaft retaining plugs and rear cover.
- On the 4-cylinder engines, position the rocker shafts so that the camshaft retaining plate ends can be engaged in the slots of shafts during camshaft installation.
- Adjust the valve clearance.
See Figure 3
The cylinder head must be removed before the rocker arm shafts can be removed.
- Disconnect the negative battery cable. Remove the cylinder head.
- Mount the head on a suitable holding fixture.
- Remove the camshaft sprocket bolt and remove the camshaft distributor adapter and sprocket. Reinstall the 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 spring-clips from the rocker arms by lifting them off.
Remove the exhaust side rocker arm shaft:
- Set the No. 6 cylinder rocker arms at the valve overlap position (rocker arms parallel), by rotating the camshaft through the firing order.
- Push in on the front cylinder rocker arm and then turn the camshaft in the direction of the intake rocker shaft, using a 1 / 2 inch drive breaker bar and a deep well socket to fit over the camshaft adapter. Slide each rocker arm to one side as it develops sufficient clearance away from its actuating camshaft and the valve it actuates. Rotate the camshaft until all of the rocker arms are relaxed.
- Remove the rocker arm shaft by driving it out or pulling it out.
Remove the intake side rocker arm shaft:
- Turn the camshaft in the direction of the exhaust rocker arm.
- Use a deep well socket and a 1 / 2 inch drive breaker bar on the camshaft adapter to turn the camshaft. Slide each rocker arm to one side as it develops sufficient clearance away from its actuating camshaft and the valve it actuates. Rotate the camshaft until all of the rocker arms are relaxed.
- Remove the rocker arm shaft.
Install the rocker arm shafts by reversing the removal procedure. Keep the following points in mind:
- The large oil bores in the rocker shafts must be installed downward, toward the valve guides and the small oil bores and grooves for the guide plate face inward toward the center of the head.
- The straight sections of the spring clamps must fit into the grooves in the rocker arm shafts.
- The guide plate must fit into the grooves in the rocker arm shafts.
- Adjust the valve clearance.
See Figure 4
To replace the rocker arms on the 524td, it is necessary to use a special tool which allows the valve involved to be opened, and works against the camshaft. Use BMW Tool 11 3 120 or the equivalent. It is also necessary to have a special tool designed to remove the rocker pivots from the head. Because these are retained by an adhesive, it will be necessary to get an adhesive designed to retain the rocker pivots on this engine. It is also necessary, of course, to have the special tools required to adjust the valves after the rockers have been replaced.
- With the cylinder head attached to the engine block, remove the cam cover. Turn the engine over with a wrench on the crankshaft pulley so the cams that drive the vacuum pump (mounted over the camshaft) are pointed downward. Then, remove the attaching nuts and remove the vacuum pump.
- Pull off the spring clip for each rocker being replaced. Turn the crankshaft so the cams involved are pointing downward.
- Locate the special valve spring compression tool around the camshaft. Make sure that if the valve will not depress easily, the crankshaft is turned. If the piston is right near top dead center, the valve may hit it. Also, make sure not to depress the valve spring retainer while the valve remains stationary, which could permit the retaining collets to come loose. When there is sufficient clearance to permit the rocker to clear the ball on the top of the pivot ballstud, remove it by sliding it out from under the camshaft.
- Remove the ballstud by clamping the special tool on it and pulling it out.
- Coat a new ballstud with the required adhesive and install it, pressing it in until it hits the stop. Do not replace the rocker arm without also replacing the ballstud. If re-using parts, retain ballstuds and rockers in order so the same parts will be used together.
- Install the rocker(s) in reverse order. Press the spring clip into the groove in the top of the ballstud from the outboard side so the end of the clip will retain the rocker. Adjust the valves as described in this section.
- Install the vacuum pump with the cams that are under it turned downward. Make sure that the vacuum pump pipe is at the rear and that its drive cam will line up with the follower on the pump plunger. Make sure to install the seal on the pipe. Replace the cam cover in reverse or removal.