Nissan Murano Z50 Valve Adjustment: A Complete Guide

Engine Nissan Murano Z50 The VQ35DE series is famous for its power and smoothness, but requires careful attention to the gas distribution mechanism. Unlike modern engines with hydraulic compensators, this power unit is equipped with mechanical pushers, which require adjustment of the clearances over time. Ignoring this process leads to loss of dynamics and the appearance of extraneous noise in the engine compartment.

Many owners Nissan They mistakenly believe that valve adjustment is a complex procedure available only to dealers. In fact, if you have the right tool and understanding of the operating principle, you can perform the operation yourself, saving a significant amount on the services of a service center. The main thing is to observe the temperature regime and the accuracy of measurements.

Why it is necessary to adjust the valves on the Murano Z50

The main reason for the need for the procedure is the natural wear of the rubbing surfaces between the camshaft cams and pushers. Over the course of the mileage, the gaps increase, which leads to a characteristic metallic knock, reminiscent of a crackling or clattering sound. This sound is especially noticeable when the engine is cold and may change as the engine speed increases.

In addition to noise, incorrect clearances affect valve timing, which reduces engine power and increases fuel consumption. If the gap is too large, the valve does not open to the required amount, impairing the filling of the cylinders with the mixture. If the gap is too small, the valve may not close completely, which leads to burning of the seats and loss of compression.

Engine Feature VQ35DE is that it uses pushrods of varying thicknesses for tuning. This means that to correct the gap you do not need to tighten the screws, but rather replace the pusher washer with a part with a different rating. The process is labor-intensive, as it requires removing the camshafts to access the mechanism.

Symptoms and service intervals

The first signal about the need for intervention is extraneous noise. If you hear a distinct metallic knocking sound at the top of the engine that disappears or changes as the speed changes, this is a sure sign of increased clearances. It is also worth paying attention to the loss of throttle response of the car during acceleration.

The manufacturer does not specify strict replacement regulations, but experienced technicians recommend checking the condition every 60,000 - 80,000 km. In urban operating conditions with frequent traffic jams and overheating, this interval may be reduced. Failure to check may result in more expensive cylinder head repairs required in the future.

It is important to distinguish between the knocking of valves and the knocking of hydraulic compensators or a chain drive. For engine Nissan Murano The knocking of valves during a cold start is typical. If the sound does not go away after warming up, the problem may be more serious than just clearance, and the condition of the valve seats may need to be diagnosed.

⚠️ Attention: Do not confuse the knocking of valves with the knocking of the timing chain drive. Chain on VQ35DE located in the front of the engine and has a characteristic metallic ringing sound, which often intensifies when starting. Incorrect diagnosis can lead to replacing the pushers when the problem was in the chain tensioner.

Necessary tools and preparation

To get the job done you will need a standard set of wrenches, sockets and a torque wrench. Pay special attention to the set of gap gauges. The probes must be of high quality, with precise thickness, since the result of the entire work depends on this.

• 🔧 Set of 10, 12, 14, 17 and 21 mm sockets for dismantling components
• 📏 Set of flat probes (from 0.10 to 0.50 mm) for accurate measurements
• 🔨 Lightweight hammer and drift for knocking out pushers
• 🧴 Special cleaner and lubricant for camshafts
• ⚙️ Set of adjusting washers (thickness from 1,200 to 2,730 mm)

Allow the engine to cool completely before starting work. The optimal temperature for measurements is 20–25 degrees Celsius. Any measurements taken on a hot engine will be incorrect due to thermal expansion of the metal. This is critical to obtaining accurate data.

Also have clean rags and containers ready to catch the oil. When removing the valve cover, a small amount of oil will inevitably spill from the timing channel. Cleanliness in the work area will prevent dirt from entering the gas distribution mechanism, which could lead to accelerated wear of parts.

Step-by-step removal and measurement procedure

The first step is to remove the valve cover. Disconnect all crankcase ventilation hoses and wires that interfere with access. Remove the cover bolts, following the unscrewing order from the edges to the center to avoid deformation of the gasket. Carefully pry the cover and remove it, being careful not to damage the O-ring.

Next, you need to set the piston of the first cylinder to the top dead center (TDC) of the compression stroke. To do this, rotate the crankshaft by the pulley clockwise until the mark on the pulley coincides with the mark on the timing cover, and the camshaft cams of the first cylinder should look up. This will allow you to measure the clearances on the intake and exhaust valves of the first cylinder.

The measurement is made with a feeler gauge, which is inserted between the camshaft cam and the top of the tappet. The probe should pass with little effort. If it goes in too easily or doesn't go in at all, the gap is out of tolerance. Record all the obtained values ​​in the table for subsequent calculation of the thickness of the washers.

After removing the valve cover and setting TDC, it is necessary to remove the camshafts. Unscrew the camshaft bed bolts in several passes to evenly release the spring pressure. Remove the bed and carefully remove the shafts, being careful not to damage the cams and journals. Place them on a clean surface in the correct order.

Now you can remove the pushers. Use a magnetic stick or a special hook to remove them from the glasses. For each pusher, you need to write down its current number and the measured gap. This will allow you to accurately calculate the required thickness of the new washer. Do not mix up the pushers, as they have individual wear.

⚠️ Attention: Use extreme caution when removing the pushrods. If the washer falls inside the engine, removing it will require complete disassembly of the cylinder block. Use a magnetic tool and work over a closed rag to catch the puck if it accidentally drops.

How to calculate the pusher number correctly?

A number is stamped on the end of the pusher, which indicates its thickness in hundredths of a millimeter. For example, number 42 corresponds to a thickness of 2.420 mm. If the number is erased, measure the thickness with a micrometer to the nearest 0.001 mm.

Calculation of the thickness of new washers

The new washer is calculated using a simple formula: New thickness = Current thickness + (Measured gap - Standard gap). For intake valves, the standard is 0.20–0.30 mm, for exhaust valves – 0.28–0.38 mm. These values ​​may vary slightly depending on the engine version, so check the technical documentation.

Calculation example: If the current washer thickness is 2.450 mm, and the measured gap is 0.50 mm with a standard of 0.25 mm, then the difference is 0.25 mm. This means that the new washer should be 0.25 mm thicker. Total thickness: 2.450 + 0.25 = 2.700 mm. Round the result to the nearest available puck value.

015 mm. If the calculated value falls between two available thicknesses, select the closest value, but try not to exceed the allowable limit. Too much reserve may cause the valve to open less than it should.

Valve type	Standard clearance (cold)	Permissible deviation	Action
Inlet	0.20 – 0.30 mm	±0.05 mm	Washer selection
Outlet	0.28 – 0.38 mm	±0.05 mm	Washer selection
Intake (wear)	More than 0.40 mm	Critical	Urgent replacement
Graduation (wear)	More than 0.50mm	Critical	Urgent replacement

After selecting the washers, install them back into the pushers. Make sure the washer is tight and not loose. Insert the pushers into their sockets, strictly observing the markings. Incorrect tappet installation can cause rapid wear of the camshaft lobe.

Installation of camshafts and final assembly

Before installing the camshafts, apply clean engine oil to the journals and cams. This is necessary to prevent dry friction when the engine is first started. Install the shafts into the cylinder head, observing the correct orientation of the marks. The valve timing marks must match the marks on the body.

Install the camshaft bed and tighten the bolts with a torque wrench. Tightening is carried out in several passes according to the pattern from the center to the edges. The tightening torque is usually around 10-12 Nm for main bolts and 8-10 Nm for cover bolts. Following the tightening order prevents bed deformation and shaft jamming.

After installing the shafts, turn the engine two full revolutions of the crankshaft and check the clearances again. This will ensure that the calculations are correct and the mechanism is working correctly. If the gaps have changed, repeat the procedure for selecting washers. The final check should be carried out on a cold engine.

Install the valve cover with a new gasket. Apply sealant to the joints (usually the corners of the camshaft bed), if required by the design. Secure the cover with bolts, tightening them evenly. Connect all hoses and wires that were previously removed.

Start the engine and listen to the operation. The knocking noise should disappear or become barely noticeable. Let the engine idle for a few minutes, checking for oil leaks. After this, you can take a short trip to check the engine operation under load.

Common mistakes and expert advice

One of the most common mistakes is neglecting cleanliness. Even a small speck of dust getting into the timing mechanism can lead to scuffing on the camshaft cams. Always work in a clean area and use clean tools. Do not use compressed air to blow through parts as it may spray dirt.

Another mistake is improper tightening of the camshaft bed bolts. If the bolts are tightened too much or unevenly, the shafts may become distorted, causing them to seize or wear out quickly. Always use a torque wrench and follow the recommended tightening pattern.

Some mechanics try to adjust the clearances without removing the camshafts, using the "by ear" method or rough feeler gauges. This is unacceptable for the engine VQ35DE. Accurate adjustment requires access to the pushers and their replacement. Trying to save time may cost you a major engine overhaul.

It is also worth noting that with high mileage, wear may be observed on the camshaft cams. If the wear is significant, simply replacing the washers will not solve the problem and the camshafts will need to be replaced. This is an expensive procedure, so regularly checking clearances helps to detect wear early.

What to do if there are no suitable washers?

If the calculated washer thickness does not match the available ratings, you can use the two-washer selection method. However, this is not recommended as it increases the risk of the puck falling out. It is better to order washers of the required thickness or combine them taking into account tolerances.

FAQ: Frequently asked questions

Is it possible to adjust the valves without removing the camshafts?

No, for the engine Nissan Murano Z50 with the VQ35DE engine, valve adjustment is only possible by replacing the pushers, which requires dismantling the camshafts. Attempts to adjust without removing the shafts are structurally impossible.

How often should valve clearances be checked?

It is recommended to check the gaps every 60,000 - 80,000 km. If a metallic knock occurs, the check should be carried out immediately, without waiting for the scheduled time.

Can washers from other engines be used?

No, the washers must strictly meet the VQ35DE engine specification. Using washers from other models may result in incorrect clearances and damage to the timing mechanism.

How long does the adjustment procedure take?

If you have experience and all the necessary tools, the procedure takes from 4 to 6 hours. For beginners, this period can be increased to 8-10 hours due to the need to carefully check each step.

Do I need to change the valve cover gasket?

Yes, when removing the valve cover it is recommended to replace the gasket with a new one. An old gasket may lose its elasticity and fail to seal properly, resulting in oil leakage.

Valve adjustment is an important procedure that will extend the life of your engine. Nissan Murano Z50. Properly performed work ensures silence in the engine compartment, smooth engine operation and optimal fuel consumption. If you are not confident in your abilities, it is better to entrust this work to professionals, but knowing the process will help you control the quality of the work performed.

Remember that the VQ35DE engine is a reliable unit that will last a long time if properly cared for. Regular checking and timely adjustment of valve clearances is the key to long and trouble-free operation of your crossover. Don't put off servicing until later, as timing problems can lead to costly repairs.

Compliance with all recommendations and the use of quality tools will ensure successful completion of the job. Be careful when measuring and calculating the thickness of the washers, and your car will delight you with impeccable performance for many years.

⚠️ Attention: It is critical to check that the timing marks match after assembly.. If the marks do not match, the engine will start, but operation will be incorrect, which can lead to a collision of the valves with the pistons and complete destruction of the engine.