Engine VK56VD, installed on Nissan Patrol fifth generation, is a complex unit with a variable valve timing system CVTCS. The reliability of this engine directly depends on the accuracy of the synchronization of the crankshaft and camshafts. Any deviation of even one tooth in the chain can lead to fatal consequences, such as the valves meeting the pistons.
The procedure for replacing a chain and setting marks requires not only special tools, but also a deep understanding of the design aluminum block and location of tensioners. Many owners Patrol Y62 are faced with the need to carry out this work due to chain stretching at high mileage. Assembly errors can cost you a major overhaul or replacement of the entire power unit.
Preparing tools and dismantling attachments
Before disassembly begins, it is necessary to ensure access to the front of the engine. This is a labor-intensive process that requires the removal of many components, including the radiator, fan and alternator. Without quality access, you simply cannot check the status chain tensioners and stars.
You will need a set of socket wrenches, a torque wrench for tightening the cylinder head studs, and special shaft clamps. Pay special attention to draining the antifreeze and oil, since when removing the front cover, residual liquids will inevitably leak out.
- 🔧 Set of keys and sockets (including torque)
- ⚙️ Special clamps for camshafts and crankshaft
- 🛢️ Containers for draining technical fluids
- 🧼 Carburetor cleaner and degreasing rags
Removing the timing chain and troubleshooting components
After removing the cover, you will see a complex system of chains. In the engine VK56VD a system of two circuits is used: main and intermediate. It is important to remember or photograph the location of all gears before removing them. Chain tensioners often jam or lose pressure, which leads to marks jumping.
Before removing the chain, be sure to block the crankshaft from turning. If this is not done, the tensioner spring may suddenly knock out the chain, damaging adjacent parts. Inspect the chain guides for wear - the plastic flats often crumble and clog the oil passages.
⚠️ Attention! Do not attempt to remove the tensioners without securing them with a pin or wire. The spring inside has a huge force, and if it is accidentally released, you can injure your hands or lose small parts.
- 🔍 Inspect the guides for chips and cracks
- 📏 Check the chain stretch by measuring the length of 20 links
- 🛠️ Replace all gaskets and seals
- Less than 100,000 km
- 100,000 - 200,000 km
- More than 200,000 km
- I don't know for sure
Crankshaft installation and initial synchronization
The first stage of assembly is the precise installation of the crankshaft. The mark on the crankshaft pulley must match the mark on the front engine cover. This is the base from which the rest of the gas distribution system is built. An error at this stage will make further work pointless.
Use a special clamp that is inserted into the cylinder block. It should fit tightly into the crankshaft groove, which will confirm the correct position TDC (top dead center) first cylinder. If the lock does not fit, then the shaft is not positioned correctly and the chain will have to be rearranged.
Порядок затяжки шпилек крышки: 10 Нм → 25 Нм → доворот на 90°After fixing the crankshaft, you can begin installing the oil pump drive sprocket. It is important that the mark on this sprocket matches the mark on the pump body. This is critical to the operation of the lubrication system.
- ✅ Make sure that the crankshaft lock is inserted all the way
- 🔩 Tighten the crankshaft pulley to the torque specified in the manual
- 🛢️ Check the operation of the oil pump before complete assembly
☑️ Check before installing circuits
Installation of chains and alignment of camshaft marks
The most crucial moment is installing chains on the camshaft sprockets. Each sprocket has colored marks that must strictly match the marks on the cylinder head housing. The markings for the intake and exhaust shafts are of different colors to avoid confusion.
Before tensioning the chains, you must make sure that the valve timing is set correctly. Use camshaft clamps that are applied to the cylinder head plane. If the clamps do not sit straight, it means that the marks on the chains are misaligned. One mistake in the color of the mark can result in the engine not starting or misfiring.
After installing the chains on the shafts, check the tension. Hydraulic tensioners must be removed or locked in a compressed state. Make sure the chain does not slack in any loose areas. The tension rollers must rotate freely and have no play.
Nuances of color marks
The mark on the intake camshaft sprocket is usually golden, and on the exhaust camshaft the mark is usually blue or green. There are corresponding recesses or risks on the cylinder head housing. Always check the factory diagram as colors may vary depending on the year of the engine.
- 🎨 Align the color mark of the intake shaft with the mark on the cylinder head
- 🎨 Align the color mark of the exhaust shaft with the mark on the cylinder head
- 🔒 Fix the special shafts. plate before tension
Installation of tensioners and final assembly
After the chains are installed and the marks are aligned, you can proceed to installing the hydraulic tensioners. First install the tensioners in a compressed state, then slowly release the clamps. This will allow the chain to stretch smoothly under oil pressure.
It is important to check that all tensioners are working. If any of them remain compressed, there is air in the system or a problem with the tensioner valve. Start the engine (if possible) and check for any unusual sounds. A chain knocking when cold is a sign that the tension is insufficient.
⚠️ Attention! After installing the tensioners, be sure to turn the crankshaft two turns and again make sure that all marks match. This ensures that the chain does not jump when first started.
Final assembly includes installing the front cover with a new gasket. Apply sealant only to the areas specified by the factory to prevent silicone from getting inside the engine. The cover bolts are tightened in strict sequence so as not to damage the aluminum block.
- 🔧 Set the tensioners to their original position
- 🛢️ Fill with fresh oil and check the level
- 🔊 Check engine idle speed
Before final tightening the timing cover bolts, apply a small amount of engine oil to the threads and under the bolt heads for a better seal and to prevent corrosion.
The main secret of success is consistent checking of marks after each assembly stage. Do not rely on memory, always visually check the match of the color markers with the marks on the case.
Frequent errors and problems when replacing
Even experienced mechanics sometimes make mistakes when working on an engine. VK56VD. One of the most common problems is improper installation of the oil pump sprocket. If it is skewed, the pump will quickly fail, which will lead to oil starvation of the engine.
Another common mistake is ignoring the condition of the sedatives. Old plastic parts can not only wear out, but crumble. If you do not clear the plastic from the oil passages, the new tensioner will quickly become clogged and stop working. Always flush the channels with solvent.
| element | Sign of wear | Recommendation |
|---|---|---|
| Timing chain | Elongation more than 1 mm | Mandatory kit replacement |
| Asterisks | Burrs, worn teeth | Replacement with chain |
| Hydraulic tensioner | Doesn't hold pressure | Replacement with a new original |
| Sedatives | Cracks, chips | Replacing all guides |
It is also worth paying attention to the condition of the crankshaft and camshaft seals. At high mileage they become dull and begin to leak. Replacing the seals "at the same time" will save you time and money in the future, since access to them after assembly is extremely difficult.
Post-assembly diagnostics and adaptation
After completing the work and starting the engine, it is necessary to adapt the system CVTCS. The electronic control unit must remember the new valve timing parameters. To do this, the engine must be run at various speeds for several minutes.
Check the diagnostic scanner for errors. Error codes related to phase shifters (for example, P0011, P0021) may indicate that the timing marks are incorrect or there is a problem with the oil pressure. If there are no errors and the engine runs smoothly, the job has been completed successfully.
- 📊 Connect scanner to check error codes
- 🔄 Check the operation of phase shifters at different speeds
- 🌡️ Monitor engine temperature and oil pressure
How to understand that the timing marks are set incorrectly?
If the marks are set incorrectly, the engine may not start at all, run with severe misfires, stall at idle, or produce an error in valve timing. It is also possible that a metallic knock may occur due to improper valve clearance.
Do I need to change the chains on both sides of the engine at the same time?
Yes, it is strongly recommended to change the timing chain kit on both sides of the engine at once. The life of the chains is the same, and if one is stretched, the second is also at its limit. This will save you having to disassemble the engine again in the near future.
Is it possible to use non-original spare parts for the timing belt?
The use of non-original chains and tensioners is permissible only from proven brands of the highest quality. Cheap analogues often have incorrect chain pitch or weak springs in the tensioners, which will lead to rapid re-stretching and breakage.
How often should I check the condition of the circuit on Patrol 5.6?
It is recommended to check the condition of the chain and tensioners every 100,000 km. If you hear a characteristic knocking sound when starting a cold engine (lasting more than 1-2 seconds), this is the first sign of wear and requires immediate diagnosis.
What should I do if the chain continues to knock after replacement?
First check the oil pressure in the system. If the pressure is normal, a poor-quality tensioner may have been installed or the chain may not be fully tensioned due to air in the system. In rare cases, the problem may be worn guides that have not been replaced.