Euro S50 Double Vanos Rattle Procedure

The following information is provided for reference purposes only and should be used at your own risk S50B30 (Euro) Engine
In no event shall Beisan Systems, LLC or its members be liable for incidental, consequential, or special loss or damages of any kind however caused.

Introduction (Euro S50 Double Vanos)
“Vanos” is BMW’s name for its variable valve timing units. Vanos units take on various shapes and design according to car year and model (engine model).

The Euro S50 Double Vanos discussed here is BMW part # 11-36-1-404-701. It’s a double vanos, which means that both the intake and exhaust valve timing are varied. Consequently , this vanos unit is part of the BMW 6-cylinder engine Euro S50B32. BMW incorporated this engine into three car models: the 3-series Euro E36 M3 (93-95), the Euro Z3 M Coupe (98-00), and the Euro Z3 M Roadster (96-00).

Similarly , this vanos, like most vanos designs, can develop a rattle over time. Specifically , wear in the variable valve timing helical (slanted) gears is the primary cause of the VANOS rattle. These gears are located on the camshaft sprocket and the splined shaft, which connects to the VANOS. As a result , the wear in the helical gears allows the camshaft to have lash movements that engage the splined shaft axially.

At certain RPMs , these movements resonate and engage axial play (free space), thus causing associated components to hit and rattle. Moreover , the helical gears and splined shaft bearing develop axial play, which further facilitates the rattle. Unfortunately , replacing the helical gear components is expensive, and even worse , the gears will wear again, causing the rattle to return.

Removing the axial play in the splined shaft bearing significantly reduces the rattle to the point where it becomes barely audible or inaudible in the passenger compartment. Performance cams like the ones on this engine create stronger camshaft lash forces and thus are more susceptible to causing a rattle.

The diaphragm spring, which is part of the intake and exhaust sprockets, also helps address the rattle. This spring loads the sprocket rotational movement to dampen the rattle quick movements.
Over time the diaphragm spring weakens and degrades in function. The diaphragm spring, which is part of the intake and exhaust sprockets, also helps address the rattle.
This diaphragm spring is not available as a separate part for the Euro S50 engines. Replacing the diaphragm spring with a new one is often necessary to fully resolve the rattle. Fortunately, the S54 and S62 engines also use the same diaphragm spring, and you can purchase it separately for these engines.

On the S54 engine the part number is 11-36-7-830-684. On the S62 engine the part number is 11-36-7-833-218. But with the S62 engine BMW redesigned the diaphragm spring to thicken it. This part is more effective and lasts longer.

For an in-depth discussion of the rattle cause and solution, please refer to the Beisan single and double rattle procedure and single diaphragm spring procedure introductions.

The splined shaft bearing consists of a thick washer and two thrust (roller) bearings . Importantly , the washer includes a stud that mounts directly to the VANOS piston . In turn , the two thrust bearings sandwich the washer, thereby facilitating the splined shaft to rotate at camshaft speed without rotating the Euro S50 Double Vanos piston.

This design is crucial for maintaining proper functionality within the VANOS system. By allowing the splined shaft to rotate independently , the bearing minimizes unnecessary movement and helps prevent issues such as axial play or rattling. However, over time, wear in the thrust bearings or washer can lead to increased axial play, which may result in the characteristic “VANOS rattle.”

Furthermore , addressing this issue often involves replacing or modifying the worn components, such as upgrading to stronger thrust bearings or hardened washers, to restore tight tolerances and eliminate excessive movement. This ensures smoother operation and extends the lifespan of the Euro S50 Double Vanos system. This design is crucial , as it ensures smooth operation and minimizes unnecessary movement, which can otherwise lead to issues such as axial play and rattling .

Furthermore , proper maintenance of these components is essential to prevent wear and ensure long-term performance. By understanding how these parts interact , you can better diagnose and address problems related to Euro S50 Double Vanos system noise or malfunction. This design ensures that the system operates smoothly under normal conditions, although wear over time can lead to issues such as axial play and rattling. Additionally , the washer and two thrust bearings are encased in a ring and two outer flat washers. The splined shaft cavity houses the complete bearing, and a threaded cover seals it.

In order to remove the splined shaft bearing axial play, it is necessary to modify or replace one or more bearing components. However , manufacturers produce the thrust bearings to tight tolerances, which means that they are standard parts. As a result , replacing them can be straightforward, but modifications may require additional effort.

It’s not feasible to modify or replace them. Similarly, manufacturers produce the center washer to tight tolerances. However, the ring, a non-standard part, consists of annealed (soft) standard steel. This material causes the ring to wear and score when it contacts the center washer and thrust bearings.

The outer flat washers reside inside the ring and thus influence the bearing axial fit. The washers are a standard bearing part, but due to their stamped manufacturing have a notable tolerance range which can significantly affect the bearing axial fit.
To address this issue, one effective solution is to replace the ring with one made of hardened bearing steel, ground to bearing standards. By doing so , tightly controlling its height allows you to achieve a precise bearing axial fit. Alternatively , you can opt for standard bearing washers that technicians have measured and sorted to achieve the required height for a tight axial fit. This approach ensures that the axial play is minimized, thereby reducing the likelihood of rattling and improving the overall performance of the system. During installation, you can make minor adjustments to address any variations in the axial fit.

The Euro S50 Double Vanos rattle repair kit includes two sets of replacement bearing ring and two outer washers.

Opening the splined shaft to modify the bearing requires counter holding the splined shaft and unscrewing the cover. The splined shaft doesn”t have a built in area for grabbing it, and the cover only has two holes in it to manipulate it. The cover threads also have high strength thread locker which makes the cover very difficult to remove.
To secure the splined shaft, it is essential to use a splined shaft holder tool. Similarly , for opening and closing the splined shaft cover, you should use a socket tool equipped with dowels that insert into the cover holes.

The vanos rattle tool kit includes both a splined shaft holder and a splined shaft socket. Specifically , the holder is square-shaped, designed to mount in a vise, and functions by receiving and counter-holding the splined shaft. Furthermore , the tool features a standard 1/2″ drive size and includes dowels that align with the splined shaft cover holes, allowing you to open and close the cover with precision.

In addition , this tool can be used with an impact wrench, which is particularly useful for breaking through the thread locker on the cover. As a result , the process becomes more efficient and ensures proper handling of the components without causing damage. Additionally, you can use it with a torque wrench for final tightening.

You can acquire the VANOS rattle repair and rattle tool kits from Beisan Systems (pronounced “bee-saan”) at www.beisansystems.com/products.

Symptoms

Vanos rattle at a certain RPM range, often 1800-2200 RPM. Rattle can also occur at idle.

Repair Procedure

The following procedure outlines the repair for the Euro S50 double VANOS splined shaft bearing and sprocket hub diaphragm spring rattle.

You should perform this repair in conjunction with the Euro S50 double VANOS repair procedure.
Euro S50 Double Vanos Procedure

Repair time: 3 hours mechanic, 3+ hours DIY.

Parts, Tools, and Shop Supplies

Euro S50 double vanos rattle repair kit (BS042) $80/each (www.beisansystems.com), Euro S50 vanos rattle tools (BS094) $20/each (www.beisansystems.com)

Euro S50 Double Vanos
2 x S62 sprocket hub diaphragm spring and pressure plate (11-36-7-833-218) $30.89/each

Note: The S62 diaphragm spring has been redesigned to be thicker and stronger, which significantly enhances its ability to control VANOS rattle more effectively. As a result , this upgraded component is not only compatible with the Euro S50 engine but also provides improved durability and performance. By using this part , you can address the issue of excessive axial play and reduce the likelihood of rattling, ensuring smoother operation over time.

Euro S50 Double Vanos
11mm socket 3/8″, 13mm socket 3/8″, 32mm deep socket 1/2″

Euro S50 Double Vanos
BMW camshaft alignment bridge (83-30-0-491-085) $69.73/each, BMW camshaft alignment bridge pin (83-30-0-491-086) $23.36/each
BMW crankshaft locking pin (83-30-0-490-861) $20.86/each

4″, or larger, swivel vise

Note: You must mount the vise before using it.

1/2″ impact wrench

Materials Needed:

High-strength thread locker (e.g., Loctite Threadlocker Heavy Duty (Euro Green, US Red) or Permatex Threadlocker High Strength Red)
300-400 grit sandpaper (not shown)

Repair Procedure:
Perform the repair only after removing the valve cover and setting the timing to TDC (Top Dead Center). For detailed guidance on these steps , refer to the Euro S50 double vanos procedure: Euro S50 Double Vanos Procedure .

Next , proceed with the removal of the Euro S50 Double Vanos unit along with the splined shafts. This step is crucial , as it allows access to the internal components that may be contributing to issues such as axial play or rattling. Once removed , carefully inspect the splined shaft, helical gears, and related bearings for signs of wear or damage.

After inspection , apply the high-strength thread locker to secure critical threaded components during reassembly. Additionally , use the 300-400 grit sandpaper to clean any surfaces that may require preparation before reinstallation. By following these steps meticulously , you can ensure a proper repair and restore optimal functionality to the Euro S50 Double Vanos system.

Step-by-Step Instructions:

Remove Chain Guide:
Begin by removing the chain guide to access the underlying components.
Remove Chain Guide Mounting Bolts:
Using an 11mm socket with a 3/8″ drive and a 3/8″ long-arm ratchet , carefully remove the two mounting bolts securing the chain guide in place.
Slide Back and Remove Chain Guide:
Once you remove the bolts, slide the chain guide backward along the chain and lift it out of the engine bay.Tip:
- Before proceeding , ensure the chain is properly supported to prevent it from slipping or causing misalignment during removal.
- After removal , inspect the chain guide for signs of excessive wear or damage, as these could indicate underlying issues that need addressing.

By following these steps meticulously, you can safely and effectively remove the chain guide, allowing you to proceed with further disassembly or repairs .

Remove Euro S50 Double Vanos 9 mounting bolts; 5 upper and 4 lower (5mm hex bit socket 3/8″ / 3/8″ ratchet).
Note: Upper right and left end bolts are long. The right bolt has full threading, while the left bolt has only partial threading.
Note: Lower second bolt from right also mounts Euro S50 Double Vanos ground wire.

Step-by-Step Instructions:

Optionally , inspect the bolts for signs of wear, damage, or stripping, and replace them if necessary.

Remove Vanos Bridge Bolts:
Begin by removing the bolts that secure the vanos bridge in place.

Remove Vanos Bridge Mounting Bolts:
Using a 6mm hex bit socket with a 3/8″ drive and a 3/8″ long-arm ratchet , carefully remove the four mounting bolts securing the vanos bridge.Note: The center two bolts are long , while the outer two bolts are short . Be sure to keep track of their positions to avoid confusion during reassembly.

Inspect and Organize:

Once the bolts are removed, set them aside in an organized manner (e.g., grouping them by length) to ensure proper reinstallation later.

Remove vanos bridge.
Wiggle vanos bridge while pulling up to remove Euro S50 Double Vanos bridge from engine head.
Note: Gasket sealant at base of bridge acts as adhesive mounting bridge to engine head. Wiggling bridge helps break sealant bond.

Do not remove first accessible intake hub mounting bolts.

Turn crankshaft clockwise until next two intake hub mounting bolts are in accessible position (picture) (crankshaft turning socket / 1/2″ long-arm ratchet).

Step-by-Step Instructions:

Remove 2 Accessible Intake Hub Mounting Bolts:
Using a 5mm hex bit with a 3/8″ drive , a 3/8″ ratchet , and an extension , carefully remove the two accessible intake hub mounting bolts. Refer to the provided picture for the exact bolt locations.
Adjust Crankshaft Position as Needed for Tool Access:
If the bolts are difficult to access, gently adjust the crankshaft position to improve tool access. Be cautious while doing this to avoid any unnecessary strain on the timing chain or other components.Note: Be careful not to drop the bolts into the engine. Dropping bolts can lead to serious damage or require additional disassembly to retrieve them. To minimize this risk, consider using a magnetic pickup tool or working slowly and deliberately.
Organize Removed Components:
Once the bolts are removed, place them in a secure and organized location, such as a labeled parts tray, to ensure they are easily accessible during reassembly.

By following these steps carefully, you can safely remove the intake hub mounting bolts while minimizing the risk of damage or complications. This will prepare the system for further disassembly or repairs.

Step-by-Step Instructions:

Remove 2 Accessible Exhaust Hub Mounting Bolts:
Using a 5mm hex bit with a 3/8″ drive , a 3/8″ ratchet , and an extension , carefully remove the two accessible exhaust hub mounting bolts located at the back of the exhaust sprocket. Refer to the provided picture for the exact bolt locations.
Adjust Crankshaft / Exhaust Camshaft Position as Needed for Tool Access:
If the bolts are difficult to access due to the position of the crankshaft or exhaust camshaft, gently adjust their positions to improve tool access. Be cautious while making these adjustments to avoid disturbing the timing alignment or causing unnecessary stress on the timing components.Note: Be careful not to drop the bolts into the engine. Dropping bolts can lead to serious damage or require additional disassembly to retrieve them. To reduce this risk, consider using a magnetic pickup tool or working slowly and deliberately. Additionally, you can place a clean rag or cloth below the work area to catch any falling parts.
Organize Removed Components:
Once the bolts are removed, place them in a secure and organized location, such as a labeled parts tray, to ensure they are easily accessible during reassembly. Clearly mark or separate these bolts if they differ in size or function from other bolts in the system.

By following these steps meticulously, you can safely remove the exhaust hub mounting bolts while minimizing the risk of damage or complications. This step is critical for gaining access to the necessary components and ensuring a smooth repair process.

Turn crankshaft clockwise until next two intake hub mounting bolts are in accessible position (picture).

Step-by-Step Instructions:

Remove 2 Accessible Intake Hub Mounting Bolts:
Using a 5mm hex bit with a 3/8″ drive , a 3/8″ ratchet , and an extension , carefully remove the two accessible intake hub mounting bolts. Refer to the provided picture for the exact locations of these bolts.
Adjust Crankshaft Position as Needed for Tool Access:
If the bolts are difficult to access due to the current position of the crankshaft, gently adjust the crankshaft to improve tool access. Be cautious while making this adjustment to avoid disturbing the timing alignment or causing unnecessary stress on the timing chain or related components.Note: Be extremely careful not to drop the bolts into the engine. Dropping bolts can lead to serious internal damage or require additional disassembly to retrieve them. To minimize this risk, consider using a magnetic pickup tool or working slowly and deliberately. Additionally, placing a clean rag or cloth below the work area can help catch any falling parts.
Organize Removed Components:
Once the bolts are removed, place them in a secure and organized location, such as a labeled parts tray. Clearly mark or separate these bolts if they differ in size or function from other bolts in the system to ensure proper reassembly later.

By following these steps carefully, you can safely remove the intake hub mounting bolts while minimizing the risk of damage or complications. This step is essential for accessing the necessary components and ensuring a smooth repair process.

Step-by-Step Instructions:

Remove 2 Accessible Exhaust Hub Mounting Bolts:
Using a 5mm hex bit with a 3/8″ drive , a 3/8″ ratchet , and an extension , carefully remove the two accessible exhaust hub mounting bolts located at the back of the exhaust sprocket. Refer to the provided picture for the exact locations of these bolts.
Adjust Crankshaft / Exhaust Camshaft Position as Needed for Tool Access:
If the bolts are difficult to access due to the current position of the crankshaft or exhaust camshaft, gently adjust their positions to improve tool access. Be cautious while making this adjustment to avoid disturbing the timing alignment or causing unnecessary stress on the timing chain or related components.Note: Be extremely careful not to drop the bolts into the engine. Dropping bolts can lead to serious internal damage or require additional disassembly to retrieve them. To minimize this risk, consider using a magnetic pickup tool or working slowly and deliberately. Additionally, placing a clean rag or cloth below the work area can help catch any falling parts.
Organize Removed Components:
Once the bolts are removed, place them in a secure and organized location, such as a labeled parts tray. Clearly mark or separate these bolts if they differ in size or function from other bolts in the system to ensure proper reassembly later.

By following these steps meticulously, you can safely remove the exhaust hub mounting bolts while minimizing the risk of damage or complications. This step is crucial for accessing the necessary components and ensuring a smooth repair process.

Turn crankshaft clockwise until next two intake hub mounting bolts are in accessible position (picture).

Step-by-Step Instructions:

Loosen by One Turn 2 Accessible Intake Hub Mounting Bolts:
Using a 5mm hex bit with a 3/8″ drive , a 3/8″ ratchet , and an extension , carefully loosen the two accessible intake hub mounting bolts by one full turn . Refer to the provided picture for the exact locations of these bolts.
Adjust Crankshaft Position as Needed for Tool Access:
If the bolts are difficult to access due to the current position of the crankshaft, gently adjust the crankshaft to improve tool access. Be cautious while making this adjustment to avoid disturbing the timing alignment or causing unnecessary stress on the timing chain or related components.Tip:
- Loosening the bolts by one turn is often done to relieve tension or prepare for further disassembly. Ensure that you do not fully remove the bolts at this stage unless instructed to do so.
- If you encounter resistance while loosening the bolts, double-check your tool setup and ensure you’re turning them in the correct direction (counterclockwise).

By following these steps carefully, you can safely loosen the intake hub mounting bolts while maintaining proper alignment and minimizing the risk of complications. This step is essential for preparing the system for subsequent repairs or adjustments.

Step-by-Step Instructions:

Loosen by One Turn 2 Accessible Exhaust Hub Mounting Bolts:
Using a 5mm hex bit with a 3/8″ drive , a 3/8″ ratchet , and an extension , carefully loosen the two accessible exhaust hub mounting bolts located at the back of the exhaust sprocket by one full turn . Refer to the provided picture for the exact locations of these bolts.
Adjust Crankshaft / Exhaust Camshaft Position as Needed for Tool Access:
If the bolts are difficult to access due to the current position of the crankshaft or exhaust camshaft, gently adjust their positions to improve tool access. Be cautious while making this adjustment to avoid disturbing the timing alignment or causing unnecessary stress on the timing chain or related components.Tip:
- Loosening the bolts by one turn is often done to relieve tension or prepare for further disassembly. Ensure that you do not fully remove the bolts at this stage unless instructed to do so.
- If you encounter resistance while loosening the bolts, double-check your tool setup and ensure you’re turning them in the correct direction (counterclockwise).
Precautions:
- Be careful not to drop the bolts into the engine. Dropping bolts can lead to serious internal damage or require additional disassembly to retrieve them. To minimize this risk, consider using a magnetic pickup tool or working slowly and deliberately. Additionally, placing a clean rag or cloth below the work area can help catch any falling parts.

By following these steps meticulously, you can safely loosen the exhaust hub mounting bolts while maintaining proper alignment and minimizing the risk of complications. This step is essential for preparing the system for subsequent repairs or adjustments.

Pull and jerk vanos forward to remove with splined shafts from engine head.
As needed, pry between vanos and engine head at vanos top right and left ends to pry vanos off engine head (medium putty-knife).
Note: Vanos intake and exhaust pistons will first extend out of vanos then intake and exhaust splined shafts will come out of associate sprocket hubs.

Take vanos to work bench.

Removal of sprocket hubs

Step-by-Step Instructions:

Remove 2 Remaining Intake Hub Mounting Bolts:
Using a 5mm hex bit with a 3/8″ drive , a 3/8″ ratchet , and an extension , carefully remove the two remaining intake hub mounting bolts. Refer to the provided picture for the exact locations of these bolts.
Note: Be Careful Not to Drop Bolts into the Engine:
Dropping bolts into the engine can cause serious internal damage or require additional disassembly to retrieve them. To minimize this risk:
- Use a magnetic pickup tool to handle the bolts if they slip or fall.
- Work slowly and deliberately to maintain control of the tools and bolts.
- Place a clean rag or cloth below the work area to catch any falling parts.
Organize Removed Components:
Once the bolts are removed, place them in a secure and organized location, such as a labeled parts tray. If these bolts differ in size or function from other bolts in the system, clearly mark or separate them to ensure proper reassembly later.

By following these steps carefully, you can safely remove the remaining intake hub mounting bolts while minimizing the risk of damage or complications. This step is crucial for completing the disassembly process and preparing the system for further repairs or adjustments.

Caution: Be careful to not allow diaphragm spring and pressure plate at rear of intake hub to drop into engine when removing hub.
Step-by-Step Instructions:

Pull Intake Hub Forward Slowly:
Carefully pull the intake hub forward. As you do so, press the pressure plate at the rear of the hub into the hub itself to prevent it from falling or dropping into the engine.Note: Oil and grime often cause the pressure plate to adhere to the sprocket, making it prone to falling off when the hub is removed. Applying gentle pressure ensures the pressure plate stays in place during removal.
Pull Forward and Up on Hub to Remove:
Once the pressure plate is secured, continue by pulling the hub forward and slightly upward to fully remove it from the sprocket. Be mindful of any resistance, as components may still be adhered due to oil or other factors.Tip:
- If the pressure plate does not stay in place, use a magnetic tool or your fingers (if accessible) to hold it securely against the hub while removing the assembly.
- Work slowly and deliberately to avoid sudden movements that could dislodge the pressure plate or damage surrounding components.
Inspect Removed Components:
After removing the intake hub, inspect the pressure plate and hub for signs of wear, damage, or excessive oil buildup. Clean the components as needed before proceeding with further repairs or reassembly.

By following these steps carefully, you can safely remove the intake hub and its associated components without risking damage or loss. This step is essential for ensuring a smooth repair process and preventing potential complications.

Step-by-Step Instructions:

Remove 2 Remaining Exhaust Hub Mounting Bolts:
Using a 5mm hex bit with a 3/8″ drive , a 3/8″ ratchet , and an extension , carefully remove the two remaining exhaust hub mounting bolts located at the back of the exhaust sprocket. Refer to the provided picture for the exact locations of these bolts.
Adjust Crankshaft / Exhaust Camshaft Position as Needed for Tool Access:
If the bolts are difficult to access due to the current position of the crankshaft or exhaust camshaft, gently adjust their positions to improve tool access. Be cautious while making this adjustment to avoid disturbing the timing alignment or causing unnecessary stress on the timing chain or related components.Note: Be extremely careful not to drop the bolts into the engine. Dropping bolts can lead to serious internal damage or require additional disassembly to retrieve them. To minimize this risk:
- Use a magnetic pickup tool to handle the bolts if they slip or fall.
- Work slowly and deliberately to maintain control of the tools and bolts.
- Place a clean rag or cloth below the work area to catch any falling parts.
Organize Removed Components:
Once the bolts are removed, place them in a secure and organized location, such as a labeled parts tray. Clearly mark or separate these bolts if they differ in size or function from other bolts in the system to ensure proper reassembly later.

By following these steps meticulously, you can safely remove the remaining exhaust hub mounting bolts while maintaining proper alignment and minimizing the risk of complications. This step is crucial for completing the disassembly process and preparing the system for further repairs or adjustments.

Step-by-Step Instructions:

Adjust Crankshaft to Align Timing Marks:
Slightly rotate the crankshaft using a crankshaft turning socket and a 1/2″ long-arm ratchet until the timing marks on the engine timing cover and the crankshaft harmonic balancer align. The alignment should position the marks at approximately the 11 o’clock position when viewed from the front of the engine.
- Use a mirror if necessary to clearly view the timing marks and ensure accurate alignment.
- Rotate the crankshaft slowly and carefully to avoid overshooting the marks or causing unnecessary stress on the timing chain.
Precisely Align Sensor Bracket Hole and Harmonic Balancer Hole:
Once the timing marks are roughly aligned, fine-tune the crankshaft position to ensure precise alignment between the sensor bracket hole and the harmonic balancer hole . Refer to the provided picture for exact positioning.
- This step is critical for ensuring proper timing and alignment of the engine components. Misalignment can lead to improper sensor readings or timing issues.
- Double-check the alignment by visually inspecting both holes and confirming they line up perfectly.
Verify Alignment:
After aligning the timing marks and holes, take a moment to verify everything is correct before proceeding:
- Ensure the timing marks on the harmonic balancer and timing cover are still aligned.
- Confirm that the sensor bracket hole and harmonic balancer hole are perfectly aligned.
- If adjustments are needed, make small incremental turns of the crankshaft until everything is properly aligned.
Tip:
- If you’re unsure about the alignment, use a dowel or pin (if applicable) to temporarily hold the harmonic balancer in place while verifying the alignment.
- Be cautious not to force any components into place, as this could damage the timing system or other engine parts.

By following these steps meticulously, you can ensure the timing marks and holes are precisely aligned, which is essential for maintaining proper engine timing and avoiding potential performance issues. This step is crucial for completing the repair or adjustment process successfully.

Insert crankshaft locking pin into sensor bracket hole and harmonic balancer hole.

Step-by-Step Instructions:

Remove Chain Tensioner at Engine Exhaust Side:
Begin by locating the chain tensioner on the engine exhaust side . This component is responsible for maintaining proper tension in the timing chain.
Insert Towel Below Tensioner to Catch Draining Oil:
Before removing the chain tensioner, place a towel or absorbent cloth directly below it to catch any oil that may drain out during the removal process. This helps prevent oil spills and keeps the work area clean.
Remove Chain Tensioner (32mm Deep Socket 1/2″ / 1/2″ Long-Arm Ratchet):
Using a 32mm deep socket with a 1/2″ drive and a 1/2″ long-arm ratchet , carefully unscrew and remove the chain tensioner from its mounting point.
- Tip: Ensure you have a firm grip on the ratchet and apply steady pressure to avoid stripping the bolt or damaging the tensioner.
- Once loose, you may need to pull the tensioner out by hand, as it could be snug due to the surrounding components.
Remove and Discard Crush Washer at Base of Chain Tensioner:
After removing the chain tensioner, inspect the base where it was mounted. You will find a crush washer that seals the tensioner to prevent oil leaks.
- Carefully remove the crush washer and discard it . Do not reuse the old washer, as it is designed to compress once and may not provide a proper seal if reused.
- Note: When reinstalling the chain tensioner later, ensure you use a new crush washer to maintain a proper seal and prevent oil leaks.
Organize Removed Components:
Place the removed chain tensioner and discarded crush washer in a secure location. If reusing the tensioner, ensure it is clean and free of debris before reinstallation.

By following these steps carefully, you can safely remove the chain tensioner while minimizing oil spillage and ensuring proper preparation for reassembly. This step is essential for accessing and servicing the timing chain system effectively.

Step-by-Step Instructions:

Pull Forward Intake Sprocket to Remove from Sprocket Sleeve:
Carefully pull the intake sprocket forward to detach it from the sprocket sleeve .
- Use both hands if necessary to maintain control of the sprocket as you remove it.
- If the sprocket resists removal, gently wiggle it back and forth while pulling to help release it from the sleeve.
Remove Split Ring at Rear of Sprocket:
Once the sprocket is free, locate the split ring at the rear of the sprocket. Using a small tool such as snap-ring pliers or a flathead screwdriver, carefully remove the split ring.
- Work slowly and deliberately , as the split ring can easily slip out of place and fall.
Note: Be Careful Not to Drop Split Ring into Engine:
- The split ring is small and can easily fall into the engine if not handled carefully. To prevent this:
  - Use a magnetic pickup tool to handle the split ring if it slips.
  - Place a clean rag or cloth below the work area to catch any falling parts.
  - Work in a well-lit area to maintain clear visibility of the components.
Organize Removed Components:
After removing the split ring, place it in a secure and organized location, such as a labeled parts tray or a small container. This will ensure it doesn’t get lost and is ready for reassembly later.

By following these steps meticulously, you can safely remove the intake sprocket and split ring without risking damage or loss. This step is critical for disassembling the timing system and preparing for further repairs or inspections.

Step-by-Step Instructions:

Remove Intake Sprocket:
With the split ring and sprocket sleeve already removed, proceed to detach the intake sprocket from the assembly.
Pull Chain Up from Intake Sprocket and Remove Intake Sprocket:
- Carefully pull the timing chain upward, lifting it off the teeth of the intake sprocket.
- Once the chain is clear, gently remove the intake sprocket from its position.
- Be mindful of the chain’s position as you work, ensuring it does not slip or fall into other areas of the engine.
Lay Chain on Intake Camshaft:
After removing the intake sprocket, carefully lay the timing chain on the intake camshaft to keep it secure and prevent it from falling into the engine bay.
- Ensure the chain is positioned in a way that avoids tangling or interference with other components.
- If necessary, use a bungee cord or similar tool to hold the chain in place and maintain tension while you continue working.
Note:
- Handle the timing chain and sprocket with care to avoid damaging the links or teeth.
- Keep track of all removed components, such as the split ring and sprocket, to ensure they are ready for reassembly.

By following these steps carefully, you can safely remove the intake sprocket and manage the timing chain without risking damage or misalignment. This step is essential for accessing deeper components of the timing system and ensuring a smooth repair process.

Rotate exhaust camshaft clockwise to position cylinder 1 cams to point to right and be horizontal with engine head (picture) (24mm open wrench).

When you position the exhaust camshaft as indicated, the cylinder 2 and 4 cams will partially press on their corresponding valves (see pictures).

Adjust exhaust camshaft to achieve this position.
Note: Indicated exhaust camshaft position assures minimal loading of exhaust valves to facilitate easy and safe removal of exhaust camshaft in next steps.

Slowly and evenly loosen exhaust sprocket 14 camshaft bearing cap mounting nuts (7 bearing caps) (13mm socket 3/8″ / 3/8″ ratchet).
Initially break seize on all nuts.
Then loosen nuts 1/4 to 1/2 turn each working back and forth along camshaft.
Ensure even nut loosening by noting threads on mounting studs and nuts. Assure even pressure on camshaft by loosening tight nuts.
Loosen nuts until all nuts have no pressure. You will need to almost completely remove the nuts.

Remove bearing caps mounting nuts and bearing caps.

Caution: Be careful to not allow diaphragm spring and pressure plate at rear of exhaust hub to drop into engine when removing hub.
Step-by-Step Instructions:

1. Pull Up Sprocket with Camshaft

Carefully lift the sprocket along with the camshaft to separate it from the surrounding components.
Ensure you maintain control of both the sprocket and camshaft during this step to avoid misalignment or damage.

2. Pull Hub Forward Slowly and Press Pressure Plate into Hub

Slowly pull the hub forward while pressing the pressure plate at the rear of the hub into the hub itself.
Oil and grime often cause the pressure plate to stick to the sprocket, so take extra care to ensure the pressure plate does not detach and fall into the engine.
If the pressure plate resists, gently wiggle the hub while applying light pressure to release it.

3. Pull Forward and Up on Hub to Remove

Once the pressure plate is secured within the hub, pull the hub forward and slightly upward to fully remove it from the assembly.
Work slowly and deliberately to avoid sudden movements that could dislodge the pressure plate or damage surrounding components.

4. Lower Sprocket and Camshaft

After removing the hub, carefully lower the sprocket and camshaft back into their resting position.
Ensure they are stable and do not interfere with other components while you proceed to the next steps.

5. Removal of Splined Shafts from VANOS

With the hub and sprocket removed, proceed to detach the splined shafts from the VANOS unit.
Use appropriate tools (e.g., a splined shaft holder or socket tool) to safely extract the shafts without causing damage.
Inspect the splined shafts for signs of wear, axial play, or damage that may need addressing during reassembly.

6. Clean Outside of VANOS to Remove Dirt and Sludge

Before proceeding further, clean the exterior of the VANOS unit to remove accumulated dirt, sludge, and oil.
Use brake cleaner and a clean towel to thoroughly wipe down the VANOS housing and surrounding areas.
- Spray brake cleaner onto the surface and scrub gently with the towel to dissolve grime.
- Avoid spraying brake cleaner directly into openings or sensitive areas to prevent contamination of internal components.
Allow the Euro S50 Double Vanos unit to dry completely before handling or reinstalling it.

Tips and Precautions:

Be cautious not to drop small components , such as the pressure plate or splined shafts, into the engine. Use a magnetic pickup tool or place a protective barrier (e.g., a cloth or rag) below the work area.
Keep all removed parts organized in labeled containers or trays to simplify reassembly.
Inspect all components for wear or damage during removal, as this is an ideal time to replace faulty parts.

By following these steps meticulously, you can safely remove the sprocket, hub, and splined shafts while preparing the Euro S50 Double Vanos unit for cleaning or repair. This process ensures a smooth disassembly and minimizes the risk of complications during reassembly.

Remove vanos intake cylinder cover bolts.
Remove cover 6 mounting bolts (4mm hex bit socket 3/8″ / 3/8″ ratchet).
Note: If the bolt was not removed previously, you will find a paint drop at the base of the bolt head and on the cover. This mark is used during car assembly to verify that the bolt was fully tightened with a torque wrench.

Remove intake cylinder cover.
Pry cover at multiple locations to remove cover evenly (small putty-knife).
Note: Orient blade with edge ramp side to Euro S50 Double Vanos body. This orientation is more effective.
Note: Cover resistance is due to cover sealing O-ring.

Press intake splined shaft into Euro S50 Double Vanos to bring piston end to cylinder end (picture).

Remove vanos intake piston mounting nut.
Initially loosen nut by counter holding splined shaft stud and unscrewing nut (7mm box wrench, 4mm socket (6-point) 1/4″ / 1/4″ ratchet).
Once you loosen the nut, unscrew it by counter-holding the nut and turning the splined shaft stud (using a 7mm box wrench and a 4mm 6-point socket with a 1/4″ ratchet).

When the nut nears the end of the shaft and you can no longer hold the shaft with the tool, counter-hold the piston/shaft by hand and unscrew the nut (using your fingers and a 7mm box wrench).

Note: It is critical to use a 6-point socket, as a 12-point socket may strip the hex on the shaft.
Note: Be sure to use wrench box end, as open wrench is susceptible stripping nut hex.

Pull intake splined shaft out of intake piston and vanos.
Note: Removal resistance is due to splined shaft stud O-ring.

Remove Euro S50 Double Vanos exhaust splined shaft from exhaust piston.
Counter hold splined shaft stud and unscrew vanos exhaust piston; left hand thread (7mm open wrench, 10mm open wrench).
Note: The piston and shaft stud have a left-hand thread, so unscrew them by turning the piston tool (10mm open wrench) from right to left (as shown in the picture above).

Note: Rotate piston tool (10mm open wrench) as needed to facilitate tool access.

Installation of splined shaft rattle kit

Following procedure shows intake splined shaft but applies for both intake and exhaust splined shafts.

Removal of Splined shaft bearing

Clean splined shaft (brake cleaner & towels).
For intake splined shaft, remove O-ring at splined shaft stud center (90 degree pick).

Spray then drain cleaner through splined shaft cover holes to clear oil from bearing (brake cleaner).
Note: Removing oil from splined shaft bearing allows for bearing fit assessment in next step.

Step-by-Step Instructions:

1. Inspect Splined Shaft Bearing Axial Play

After removing the splined shaft, carefully inspect the bearing axial play to determine if it exceeds acceptable tolerances.
Axial play refers to the in-and-out (front-to-back) movement of the splined shaft stud within the bearing assembly. Excessive axial play can contribute to issues such as rattling or improper timing.

2. Hold Splined Shaft and Tilt (Rock) Stud to Each Side

Firmly hold the splined shaft in one hand and gently tilt (rock) the splined shaft stud from side to side.
Observe and note any noticeable axial play (free space) as you move the stud in and out.
- A small amount of axial play is normal, but excessive movement indicates wear or damage to the bearing components.
- Pay close attention to how much free space exists between the stud and the bearing housing.

3. Check for Axial Play by Repeatedly Inserting and Withdrawing the Stud

Alternatively, you can check for axial play by repeatedly inserting and withdrawing the stud into and out of the splined shaft.
As you do this, feel for any looseness or excessive movement that suggests the bearing has developed significant axial play.
- If the stud moves too freely or feels loose, it confirms the presence of excessive axial play.

4. Note: Radial Play vs. Axial Play

Radial play , which is the side-to-side (rotational) movement of the splined shaft, is normal and necessary for proper operation. Do not confuse this with axial play.
Focus only on axial play , which is the in-and-out movement along the axis of the splined shaft. Excessive axial play is a sign of wear in the bearing components and should be addressed.

5. Determine Next Steps Based on Inspection

If excessive axial play is detected:
- The splined shaft bearing components (e.g., thrust bearings, washers, or rings) likely need to be replaced or modified to eliminate the free space.
- Refer to repair procedures or replacement part specifications to address the issue effectively.
If no significant axial play is observed:
- The bearing is likely still within acceptable tolerances, and further disassembly may not be necessary unless other symptoms persist.

Tips and Precautions:

Perform this inspection in a well-lit area to ensure accurate observations.
Use clean hands or gloves to avoid contaminating the splined shaft or bearing components with dirt or grease.
Keep track of all measurements or observations for reference during reassembly or when consulting repair manuals.

By carefully inspecting the splined shaft bearing for axial play, you can identify potential issues early and take corrective action to ensure smooth operation of the Euro S50 Double Vanos system. This step is critical for diagnosing and addressing problems related to rattling or improper timing.

Step-by-Step Instructions:

1. Open Vise Jaws as Far as Necessary to Insert Splined Shaft Holder

Begin by opening the vise jaws wide enough to accommodate the splined shaft holder .
Ensure there is sufficient clearance to insert the holder without forcing it or damaging the vise or tool.

2. Insert Splined Shaft Holder in Vise and Align Top to Vise Jaw Top

Carefully place the splined shaft holder into the vise, ensuring it is properly seated and aligned.
Align the top of the splined shaft holder with the top of the vise jaws for stability and even pressure distribution during tightening.

3. Strongly Tighten Vise on Splined Shaft Holder

Once the splined shaft holder is properly positioned, use the vise handle to strongly tighten the jaws around the holder.
Ensure the holder is securely clamped to prevent any movement during subsequent operations, such as removing or installing components on the splined shaft.
- Tip: Avoid over-tightening to the point of damaging the splined shaft holder, but ensure it is firm enough to withstand applied forces.

Additional Notes:

Proper alignment of the splined shaft holder in the vise is critical to avoid misalignment or uneven pressure, which could lead to slippage or damage.
If the splined shaft holder has a specific orientation (e.g., a groove or marking), ensure it is positioned correctly before tightening.

By following these steps meticulously, you can safely secure the splined shaft holder in the vise, providing a stable platform for performing precise work on the splined shaft. This step is essential for ensuring safety and accuracy during repairs or modifications.

Insert splined shaft in splined shaft holder.

Install splined shaft socket on splined shaft and insert socket pins into splined shaft cover holes.
Note: The socket pins fit tightly into the splined shaft cover holes, so you may need to rock the socket slightly to fully insert the pins.

Ensure the socket pins are fully inserted into the splined shaft cover holes and the socket is fully seated on the cover.

Loosen (break seize) splined shaft cover (splined shaft socket / 1/2″ impact wrench).
If available, set impact wrench power to lowest setting.
Engage impact wrench in reverse for 3 second intervals at a time until cover loosens (seize breaks).
Note: Hold down impact wrench for control.

Remove splined shaft cover (splined shaft socket / 1/2″ ratchet).
Note: Splined shaft cover will turn with difficulty due to thread locker.
Bearing top washer will likely be bound to splined shaft cover inner recess and come out with cover.

Step-by-Step Instructions:

1. Remove Splined Shaft Center Washer / Stud (Hand):

Using your hand, carefully grasp and remove the splined shaft center washer / stud from the splined shaft assembly.
Note: The splined shaft stud is integral with the bearing center washer , meaning they are a single, unified component and will come out together.

2. Observe Bearing Top Thrust (Roller) Bearing:

As you remove the center washer / stud , notice that the bearing top thrust (roller) bearing will also come out along with the stud and center washer.
This is because the thrust bearing sits on top of the center washer and is held in place by the assembly’s configuration.

Additional Notes:

Handle the components gently to avoid dropping or damaging the small parts, such as the roller bearing or washer.
Tip: If the components feel stuck due to oil or grime, use a gentle twisting motion while pulling to help release them. Avoid using excessive force to prevent damage.
Keep all removed parts organized in a labeled container or tray to ensure they are ready for inspection, cleaning, or reassembly later.

By following these steps carefully, you can safely remove the splined shaft center washer / stud and associated thrust bearing without causing damage or misplacing components. This step is crucial for disassembling the splined shaft bearing system and preparing it for inspection or repair.

First, remove the bottom thrust (roller) bearing.
Next, insert the pick tip between the thrust bearing inner bottom and the bottom washer.
Then, carefully pry the thrust bearing out using a 90-degree pick.

First, remove the bearing outer ring. Next, place a towel on the table. Then, take the splined shaft out of the holder, tilt it upside down, and gently hit it on the towel. As a result, the bearing ring should dislodge inside the splined shaft. Afterward, carefully remove the bearing ring with your index finger. However, if the bearing ring tilts and binds inside the splined shaft, press it down to remount it, and then try removing it again. Finally, reinstall the splined shaft into the splined shaft holder.

Remove bearing bottom washer.
Insert pick tip between washer inner bottom and splined shaft and pry washer out (90 degree pick).

Cleaning of Splined Shaft Parts

Step 1: Start by cleaning the bearing parts using brake cleaner and towels.
Note: It is important to ensure the bearing parts are thoroughly cleaned. This step is necessary to properly assess the new bearing’s axial fit.

Step 2: Next, remove the old thread locker from the cover and housing thread. Use a pick tool to press the tip into the thread valley and run the pick throughout the thread (90-degree pick).
Note: It is critical that the old thread locker is fully removed to allow the new thread locker to bond effectively with the parts.

Step 3: After that, clean the splined shaft bearing cavity and cover using brake cleaner and towels.

Installation of Splined Shaft Bearing

Step 4: Finally, replace the bearing ring, as well as the top and bottom washers, with new parts.

Bearing parts installation sequence from right to left.
Bearing parts from left to right: Cover, top washer, top thrust bearing, center washer / stud, bottom thrust bearing, bottom washer, bearing ring.

Insert new bearing ring in splined shaft (fingers).
Note: New ring is marked “BS” on outer perimeter.
Initially insert ring in splined shaft.
Insert right and left index fingers into ring. Press fingers against ring inner right and left walls and manipulate ring side to side while slightly pressing down to facilitate ring full insertion.

Rotate position of fingers 90 degrees and repeat ring insertion to verify full insertion.
Note: Ring should fully mate with splined shaft bottom (picture).

Insert bearing bottom washer in splined shaft bearing ring.
Note: Splined shaft bearing top and bottom washers are interchangeable. Also washer faces are same thus washer can be inserted in either orientation.

Insert bearing bottom thrust (roller) bearing in splined shaft bearing ring.
Note: Splined shaft bearing top and bottom thrust bearings are interchangeable. Also thrust bearing faces are functionally same thus thrust bearing can be inserted in either orientation.

Insert bearing center washer / stud in splined shaft bearing ring.

Insert bearing top thrust (roller) bearing onto splined shaft stud and in splined shaft bearing ring.
Note: Thrust bearing faces are functionally same thus thrust bearing can be inserted in either orientation.

Insert bearing top washer in splined shaft cover inner cavity.
Apply some oil to splined shaft cover inner cavity.
Insert bearing top washer in cover cavity.
Note: Washer will bind to cover due to oil.
Note: Mounting bearing top washer to cover inner cavity allows for cover installation without bearing top washer interference.

Install splined shaft cover with bearing top washer onto splined shaft (splined shaft socket / 1/2″ ratchet).

When splined shaft cover is fully installed its top will be even with splined shaft rim (picture).
If cover is higher than splined shaft rim then bearing parts are not installed correctly and interfering with cover installation. Remove cover and reinstall bearing parts.

Fully tighten splined shaft cover, 55 Nm (40.5 ft-lb) (splined shaft socket / 3/8″ torque wrench & 3/8″ to 1/2″ socket adapter).

Inspection and adjustment of splined shaft bearing

Inspect splined shaft bearing axial play.
Hold splined shaft and rotate splined shaft stud to note resistance to rotation.
Hold splined shaft and tilt (rock) splined shaft stud to each side to note bearing axial play (free space).
Note: Axial fit cannot be properly assessed until splined shaft cover is fully tightened.
Note: Radial play, side to side movement, is normal and necessary. This should not be confused with axial play, in/out movement.

If splined shaft stud binds and is difficult to rotate then axial fit is too tight and loosening adjustment is needed.
If splined shaft stud has any tilt movement then axial play is present and tightening adjustment is needed.
Any level of resistance (pre-load), without binding, in splined shaft stud rotation indicates no axial play and is considered an optimal fit.

Bearing loosening adjustment.
If splined shaft binds and is difficult to rotate then axial fit it too tight and loosening adjustment is needed.
Disassemble splined shaft bearing per above procedure.
Place sandpaper (300-400 grit) on flat table top. Place bearing outer washer on sandpaper.
Slide washer side to side on sandpaper ~6″ back and forth while moderately pressing washer on sandpaper. Perform sanding for 10 seconds.
Rotate washer 90 degrees and repeat sanding process.
Flip washer to opposite side and repeat above sanding procedure; 10 seconds sanding, rotate 90 degrees, 10 seconds sanding.
Clean washer (brake cleaner & towels).
Repeat washer sanding for second outer washer.
Reassemble splined shaft bearing per above procedure and reassess bearing axial fit.
Note: Washers are made from hardened steel and do not easily wear. Sanding procedure will remove ~.0025mm washer height, total ~.005. Washers might need max .01mm height adjustment.

Bearing tightening adjustment.
If splined shaft has any tilt movement then axial play is present and tightening adjustment is needed.
Disassemble splined shaft bearing per above procedure.
Place sandpaper (300-400 grit) on flat table top. Place bearing ring on sandpaper.
Slide ring side to side on sandpaper ~6″ back and forth while moderately pressing ring on sandpaper. Perform sanding for 5 seconds.
Rotate ring 90 degrees and repeat sanding process.
Flip ring to opposite side and repeat above sanding procedure; 5 seconds sanding, rotate 90 degrees, 5 seconds sanding.
Clean ring (brake cleaner & towels).
Reassemble splined shaft bearing per above procedure and reassess bearing axial fit.
Note: Ring is made from hardened steel and does not easily wear. Sanding procedure will remove ~.005mm ring height. Ring might need max .01mm height adjustment.

Once splined shaft bearing fit is assessed, and if needed adjustment performed, thread locker needs to be applied to splined shaft cover.
Remove splined shaft cover from splined shaft per above procedure.
Apply thread locker at middle of threads along perimeter of cover (high strength thread locker).
Reinstall splined shaft cover and fully tighten per above instructions.

For intake splined shaft, reinstall splined shaft stud O-ring.
Insert O-ring on splined shaft stud and roll O-ring down stud and drop into groove (fingers).

Installation of vanos seals and cleaning of parts

Follow Euro S50 double vanos procedure sections for installation of vanos seals and cleaning of parts, Euro S50 Double Vanos Procedure

Installation of splined shafts on vanos

Insert intake splined shaft stud fully into intake piston from vanos inboard side.
Brace piston end from vanos outboard side and insert splined shaft stud into piston.
Note: Insertion resistance is due to splined shaft stud O-ring.

Install intake piston / splined shaft mounting nut.
Screw nut on splined shaft stud (fingers).
Counter hold piston/shaft by hand and screw nut (fingers, 7mm box wrench).
Note: Nut can only be slightly installed on shaft. This allows slight section of shaft stud to protrude from nut and allow counter holding shaft in next step.
Fully mount nut by counter holding nut and screwing on shaft stud (7mm box wrench, 4mm socket (6 point) 1/4″ / 1/4″ ratchet).
Note: At first, shaft tool (4mm socket) will only barely mount on splined shaft end.

Install vanos intake cylinder cover.
Orient cover with side slight indent to vanos oil filter cap (picture right).
Initially install vanos intake cover 6 mounting bolts (4mm hex bit socket 3/8″).

Fully tighten intake cover 6 mounting bolts.
Tighten bolts evenly to draw cover evenly to vanos body.
Fully tighten, 5 Nm (4 ft-lb) (4mm hex bit socket 3/8″ / 3/8″ torque wrench).
Note: Tighten bolts evenly in multiple passes. Verify one pass with all bolts fully tightened.

Install exhaust splined shaft onto exhaust piston.
Thread splined shaft stud into piston; left hand thread.
Note: Splined shaft stud and piston threads are left hand thread. Thus turn splined shaft stud counter clockwise to thread into piston thread.
Thread splined shaft stud fully into piston by rotating splined shaft stud; left hand thread (hand).

Tighten splined shaft stud to piston; left hand thread (10mm open wrench / 7mm open wrench).
Note: Due to left hand thread, it is not necessary to over tighten joint.

Installations of sprocket hubs

Remove and discard sprocket hubs old diaphragm springs and pressure plates.
Clean sprocket hubs (brake cleaner & towels).

Install new diaphragm spring, cup side down, into each sprocket hub.

Install new pressure plate into each sprocket hub. Align pressure plate and hub keys.

Warning: Do not mix combine old and new diaphragm spring and pressure plate parts as dimensions have been changed.

Verify exhaust sprocket left side slot orientation to engine head. Slot bottom end should be above head top surface (picture).
Rotate sprocket clockwise as needed to achieve orientation.
Note: Slot orientation is necessary in coming steps for installation of hub bolts.

Install exhaust sprocket hub with new diaphragm spring and pressure plate onto exhaust sprocket.
Hold pressure plate on hub to keep from sliding of and dropping into engine.
Lift up sprocket with camshaft. Insert hub into sprocket sleeve. Lower sprocket and camshaft.
Note: Sprocket slot orientation might be disturbed. This is acceptable as it is checked and adjusted in future steps.

Verify and adjust exhaust camshaft as needed for cylinder 1 cams to point right and be horizontal as before (picture).
Install 7 exhaust camshaft bearing caps in their mounting locations. Note: Caps are numbered.

Install 14 exhaust bearing cap mounting nuts on cap studs with only one nut rotation.
Start at front and work to rear. Lift sprocket as needed to install rear cap nuts.

Slowly and evenly tighten 14 exhaust bearing cap mounting nuts (7 bearing caps) (13mm socket 3/8″ / 3/8″ ratchet).
Tighten nuts 1/4 to 1/2 turn each working back and forth along camshaft.
Ensure even nut tightening by noting threads on mounting nuts and studs. Assure even pressure on camshaft by tightening loose nuts.
Tighten nuts until all nuts are fully mounted.

Fully tighten 14 exhaust bearing cap mounting nuts, 20 Nm (16 ft-lb) (7 bearing caps) (13mm socket 3/8″ / 3/8″ torque wrench & extension).
Note: Tighten nuts evenly in multiple passes. Verify one pass with all nuts fully tightened.

Rotate exhaust camshaft counter clockwise and position camshaft groove on first guide bearing to be roughly aligned with groove on first bearing cover (picture) (24mm open wrench).

Hold exhaust sprocket to keep from rotating and lift chain at intake camshaft to take up all chain slack.
Place object between intake camshaft and chain to maintain chain tightness.

Rotate split ring at rear of exhaust sprocket to position split ring gap at camshaft tooth gap at right side (picture).
Note: Split ring gap positioning allows visual inspection of sprocket slot at location.
A sprocket slot end should be aligned ~1/4 up on tooth gap (picture).
Note: Sprocket slot orientation is needed for hub bolt access in future steps.

If sprocket slot end is not aligned to indicated position, rotate exhaust sprocket clockwise (car front orientation) to achieve slot alignment.
Remove chain tensioning object and feed chain down on right side of intake sprocket to allow exhaust sprocket clockwise rotation.
Position exhaust sprocket for slot positioning then tension chain again at intake sprocket and maintain with object as before.

Hold exhaust sprocket to keep from rotating and insert tool between exhaust sprocket and engine head to lock exhaust sprocket from rotating (medium flathead).

Install intake sprocket on intake camshaft sleeve.
Remove chain tensioning object.
Position sprocket for a slot bottom end to be approximately at head surface on left side (picture).
Install chain on sprocket and mount sprocket on camshaft sleeve.
Check sprocket slop positioning and reinstall sprocket as needed to achieve position.
Note: Sprocket slot orientation is needed for hub bolt access in future steps.

Remove exhaust sprocket holding tool (flathead).
Rotate exhaust sprocket counter clockwise (car front orientation) to position as if chain tensioner is installed.
Check sprocket slot at rear right of sprocket has slot end at bottom of camshaft tooth gap (picture).
If sprocket slot position not as indicated, remove intake sprocket and repeat above exhaust sprocket and intake sprocket positioning procedures.
Note: Sprocket slot orientation is needed for hub bolt access in future steps.

Install split ring at rear of intake sprocket.
Orient split ring with flat face to front. Open split ring and place at rear of intake sprocket with hinge at top.
Slide intake sprocket forward and install split ring at rear of intake sprocket.
Slide intake sprocket back on sprocket sleeve.

Rotate intake split ring to position split ring gap between two sprocket right side slots (sprocket rear orientation) (picture).

Adjust intake split ring slightly as needed to align bolt holes at sprocket slots (picture).

Install intake sprocket hub with new diaphragm spring and pressure plate onto intake sprocket.
Hold pressure plate on hub to keep from sliding of and dropping into engine.
Slide bub onto sprocket sleeve.
Rotate hub to align holes to split ring holes (picture).

Install 2 intake hub mounting bolts at hub top two mounting holes (picture) (5mm hex bit 3/8″ / 3/8″ extension).
Tighten bolts by hand then loosen approximately one rotation.

Rotate exhaust hub to orient hub tower tabs to be approximately at right and left side (picture).

Slightly rotate exhaust hub to position hub bolt hole at center of camshaft right tooth gap (picture).

Rotate exhaust sprocket split ring to position hinge at left of top and align holes to hub holes (picture).

Install 2 exhaust hub mounting bolts at hub right side holes (sprocket rear orientation) (picture) (5mm hex bit 3/8″ / 3/8″ extension).
Rotate sprocket counter clockwise (car front orientation) to align sprocket slots with bolt holes.
Tighten bolts by hand then loosen approximately one rotation.

Install chain tensioner with new crush washer (32mm deep socket 1/2″ / 1/2″ long-arm ratchet).
Tighten tensioner a further ~1/2 turn after initial tightness to crush washer.

Installation of vanos with splined shafts

Install vanos alignment bridge without alignment dowel on engine head at cylinder 3 (picture).
Note: Bridge has intake and exhaust orientation. E is intake and A is exhaust in German.
Insert bridge alignment dowel through bridge intake side hole and insert dowel into intake camshaft alignment hole.
Note: Lift up bridge intake or exhaust ends as necessary to align and insert dowel into camshaft hole.
Rotate intake camshaft at hex at cylinder 2 to align camshaft alignment hole perpendicular to engine head and allow bridge ends to sit on engine head (24mm open wrench).
Fully insert bridge dowel into camshaft and onto bridge (picture). Turn and press down dowel as needed to fully insert.
Place hand on middle of bridge and rock intake camshaft back and forth to identify and set camshaft in position where bridge intake and exhaust ends are sitting flat on engine head.

Remove alignment dowel from bridge.

Insert bridge alignment dowel through bridge exhaust side hole and insert dowel into exhaust camshaft alignment hole.
Note: Lift up bridge intake or exhaust ends as necessary to align and insert dowel into camshaft hole.
Rotate exhaust camshaft at hex at cylinder 2 to align camshaft alignment hole perpendicular to engine head and allow bridge ends to sit on engine head (24mm open wrench).
Fully insert bridge dowel into camshaft and onto bridge (picture). Turn and press down dowel as needed to fully insert.
Place hand on middle of bridge and rock exhaust camshaft back and forth to identify and set camshaft in position where bridge intake and exhaust ends are sitting flat on engine head.

Remove alignment dowel from bridge. Remove bridge from engine head.

Move vanos ground wire forward and position end under vanos solenoid cable connector bracket.
Note(Euro S50 Double Vanos): This allows installing vanos on engine head without ground wire being caught between vanos and engine head.

Rotate intake and exhaust sprocket hubs clockwise as far as possible (hand).

Insert vanos splined shafts with pistons fully into vanos.
Clean vanos all matting surfaces (brake cleaner & towels).

Install vanos with splined shafts onto sprocket hubs.
Align and initially insert exhaust and then intake spline shafts into corresponding hubs.
Align exhaust splined shaft to insert into exhaust camshaft hole at center of hub. Rotate and insert splined shaft to insert into camshaft.
Align intake splined shaft to insert into intake camshaft hole at center of hub. Rotate and insert splined shaft to insert into camshaft.

Press vanos onto engine to insert splined shafts into camshafts and bring splined shafts slanted splines up to hubs.
Vanos press will also reinsert splined shafts and pistons fully into vanos if they came out.

Insert exhaust splined shaft slanted splines into exhaust hub.
Rotate exhaust hub counter clockwise while pressing vanos onto hub.
Splined shaft will insert into hub at first alignment of splines.

Caution: Splined shaft must insert into first available aligned hub splines.

Insert intake splined shaft slanted splines into intake hub.
Rotate intake hub counter clockwise while pressing vanos onto hub.
Splined shaft will insert into hub at first alignment of splines.

Caution(Euro S50 Double Vanos): Splined shaft must insert into first available aligned hub splines.

Press vanos onto engine head and splined shafts will insert further into hubs.
Do not fully install vanos onto engine head.

Inspect vanos oil pump side hole and exhaust sprocket hub side tab for alignment.
Rotate vanos oil pump as needed to achieve alignment (fingers).

Press vanos onto engine head and verify exhaust hub tab insertion into vanos oil pump hole.
Realign vanos pump as need to facilitate tab insertion (fingers).

Install vanos bottom right and left mounting bolts to fully install vanos onto engine head (5mm hex bit 3/8″ / 3/8″ ratchet).
Tighten bolts evenly in multiple passes to install vanos on engine head evenly.
Tighten bolts until fully mounted. Do not over tighten.

Tighten 2 intake hub mounting bolts (5mm hex bit 3/8″ / 3/8″ ratchet & extension).
Note: Do not over tighten bolts. Bolts will be fully tightened in second pass.

Tighten 2 exhaust hub mounting bolts (5mm hex bit 3/8″ / 3/8″ ratchet & extension).
Note(Euro S50 Double Vanos): Do not over tighten bolts. Bolts will be fully tightened in second pass.

Remove crankshaft locking pin.

Rotate crankshaft until next two intake hub mounting holes are in accessible position as before (picture).

Install 2 exhaust hub mounting bolts (5mm hex bit 3/8″ / 3/8″ ratchet & extension).
Adjust crankshaft rotation as needed to align mounting holes for access as before (picture).
Note: Be careful to not drop bolts in engine.
Tighten bolts evenly in multiple passes until tight.
Note: Do not over tighten bolts. Bolts will be fully tightened in second pass.

Install 2 intake hub mounting bolts (5mm hex bit 3/8″ / 3/8″ ratchet & extension).
Adjust crankshaft rotation as needed to align mounting holes for better access (picture).
Note: Be careful to not drop bolts in engine.
Tighten bolts evenly in multiple passes until tight.
Note(Euro S50 Double Vanos): Do not over tighten bolts. Bolts will be fully tightened in second pass.

Rotate crankshaft until next two intake hub mounting holes are in accessible position as before (picture).

Install 2 intake hub mounting bolts (5mm hex bit 3/8″ / 3/8″ ratchet & extension).
Adjust crankshaft rotation as needed to align mounting holes for better access (picture).
Note: Be careful to not drop bolts in engine.
Tighten bolts in multiple passes until tight.
Note: Do not over tighten bolts. Bolts will be fully tightened in second pass.

Repeat above procedure of rotating crankshaft to access two sets of intake and exhaust hub bolts at a time and fully tighten all 6 intake and exhaust hub bolts to 10 Nm (7 ft-lb).

Checking of engine timing

Turn crankshaft pulley clockwise until cylinder 1 intake and exhaust cams point to each other at ~45 degree angle (crankshaft turning socket / 1/2″ long-arm ratchet).
Note: Turning crankshaft counter clockwise is acceptable.

Adjust crankshaft slightly until timing marks on engine timing cover and crankshaft harmonic balancer at ~11 o”clock position are aligned (crankshaft turning socket / 1/2″ long-arm ratchet, mirror).
Precisely alignment timing marks. This will align sensor bracket hole and harmonic balancer hole (picture).

Insert crankshaft locking pin into sensor bracket hole and harmonic balancer hole.

Fully retard intake and exhaust camshafts. (Euro S50 Double Vanos)
For each camshaft, place open wrench (24mm combo wrench) on camshaft hex at cylinder 2 and turn camshaft counter clockwise to adjustment end position.
Message: Camshaft rotation is most effective when standing at exhaust side of car.
Memo: Rock camshaft back and forth to release bind and allow rotation.
Record: Camshafts will already be close to fully retarded position.

Install vanos alignment bridge without alignment dowel on engine head at cylinder 3 (picture).
Note: Bridge has intake and exhaust orientation. E is intake and A is exhaust in German.
Insert bridge alignment dowel through bridge intake side hole and insert dowel into intake camshaft alignment hole.
Note: Lift up bridge intake or exhaust end as necessary to align and insert dowel into camshaft hole.
Fully insert dowel into camshaft and onto bridge (picture). Rotate and press down dowel as needed to fully insert.
Bridge intake and exhaust ends should be sitting flat on engine head. Press down on each end to assess any space between bridge end and head surface.
Timing is wrong if bridge end is lifted from engine head more than .5mm.

Remove alignment dowel from bridge. (Euro S50 Double Vanos)

Insert bridge alignment dowel through bridge exhaust side hole and insert dowel into exhaust camshaft alignment hole.
Note: Lift up bridge intake or exhaust end as necessary to align and insert dowel into camshaft hole.
Fully insert dowel into camshaft and onto bridge (picture). Rotate and press down dowel as needed to fully insert.
Bridge intake and exhaust ends should be sitting flat on engine head. Press down on each end to assess any space between bridge end and head surface.
Timing is wrong if bridge end is lifted from engine head more than .5mm.

Remove alignment dowel from bridge then bridge from engine head.

Remove crankshaft locking pin.

Install chain guide.
Slide guide onto chain and mount with 2 mounting bolts (11mm socket 3/8″ / 3/8″ ratchet).
Fully tighten, 14 Nm (10 ft-lb) (11mm socket 3/8″ / 3/8″ torque wrench).

Remove vanos bottom right and left mounting bolts (5mm hex bit 3/8″ / 3/8″ ratchet).
Pull vanos forward and off engine head.

Caution: It is critical vanos oil pump rotation position not be changed. Otherwise damage can occur.

Continue repair following Euro S50 double vanos procedure, Euro S50 Double Vanos Procedure
Start at step of applying sealant to vanos bridge bottom and installing vanos bridge.

Euro S50 Double Vanos.