Car Nissan Cube first generation with body index AZ10 often found on our roads in versions with an engine HR12DE. This is a reliable unit, but like any engine with hydraulic compensators, it requires attention. The absence of adjusting screws on this engine creates the illusion of simplicity, however, when the camshaft cams or pushers wear out, the engine noise increases significantly and power decreases.
Many owners mistakenly believe that if there are no adjustment screws on the motor, then the procedure itself is impossible or requires a complete replacement of the cylinder head. In fact, for Nissan Cube the method of selecting the thickness of the adjusting washers is used. This is a more labor-intensive process that requires precision, but it allows you to restore the ideal operation of the gas distribution mechanism without replacing expensive components.
Ignoring increased noise in the valve cover area can lead to accelerated wear of the camshaft lobes. Thermal gap - this is a critical parameter on which compression and valve timing depend. In this article we will look in detail at how to independently diagnose and configure your Nissan Cube worked quietly and economically.
Preparing tools and work area
Before you begin dismantling the units, you need to make sure that you have all the necessary equipment. The process of adjusting valves on the engine HR12DE requires high measurement accuracy, so a regular set of keys will not work here. You will need specialized tools for removing and installing pushrods, as well as precision measuring instruments.
First of all, prepare a micrometer or a special feeler gauge for measuring gaps. A conventional probe may not provide the required accuracy, since the permissible deviations are calculated in hundredths of a millimeter. Also, do not forget about a set of adjusting washers of different thicknesses. Without them, replacement is not possible, so make sure you have access to a range of washers covering the range from 1.00mm to 2.50mm in 0.05mm increments.
- 🔧 Micrometer with an accuracy of 0.01 mm for measuring the thickness of washers.
- 🔩 A set of special pullers for pushers (or homemade devices).
- 🛢 Motor oil and sealant for the valve cover during assembly.
- 📏 Probes for preliminary checking of gaps (if there is no micrometer).
The workplace must be clean. Sand or metal shavings that enter the engine during disassembly can cause catastrophic wear. Valve cover It is removed neatly, without distortions. If you are planning to do this for the first time, take the time to study the design Nissan Cube and location of fasteners.
Dismantling the valve cover and removing the pulley
We start by disconnecting the battery. This is a standard safety procedure, but in this case it also prevents the starter from accidentally turning the engine. Next, you need to dismantle the plastic decorative engine casing and all attachments that interfere with access to camshafts. Typically this is the intake manifold and throttle body.
Removing the crankshaft pulley is one of the most difficult steps. The pulley bolt is highly torqued, so you will need a strong wrench or an air impact wrench. It is important to secure the crankshaft so that it does not turn. To do this, you can use a special clamp or, as a last resort, carefully wedge the flywheel through the technological hole (if there is access).
- 🛑 Prohibited use an impact tool to unscrew the camshaft bolt - you can throw off the phases.
- ⚙️ We fix the crankshaft at TDC of the first cylinder using marks on the pulley and cover.
- 🔨 We use a torque wrench to control the tightening torque during reassembly.
After removing the crankshaft pulley, we proceed to removing the camshaft pulley. You need to be extremely careful here, since the timing chain is under tension. If you do not plan to change the chain, you do not need to remove it completely, just loosen the tensioner and keep the camshaft from turning. Timing chain must remain in place so as not to disrupt the valve timing.
⚠️ Attention! When removing the camshaft pulley, be careful not to let the chain jump onto a tooth. This will lead to phase failure and the inability to start the engine after assembly.
- Very easy
- Medium difficulty
- Difficult, requires skills
- It's very difficult, I'm afraid to make a mistake
Thermal gap measurement and diagnostics
Now that access to the cams is open, you can begin the most important step - measuring the gaps. Motor HR12DE has two camshafts: intake and exhaust. It is necessary to check the clearances for all 12 valves (6 for each shaft). The engine must be cold, otherwise the metal will expand and the measurements will be incorrect.
Rotate the crankshaft clockwise, aligning the marks. To measure the first valve, install the piston of the first cylinder in TDC (top dead center) of the compression stroke. In this position, the cams of the first cylinder should point upward without touching the pushers. Measure the clearance between the cam and tappet with a feeler gauge or micrometer.
- 📐 Intake valves: normal clearance is 0.15–0.25 mm.
- 📐 Exhaust valves: normal clearance is 0.25–0.35 mm.
- 📊 Write down each measurement in the table so as not to confuse the values.
If the clearance exceeds the permissible limits, this means that the washer is worn out or the camshaft cam is worn down. If the gap is too small, it can lead to burnout of the valve due to incomplete closure. Adjusting washers operate under conditions of high temperatures and loads, so their wear is a natural process that requires periodic monitoring.
Before removing the pushers, mark the position of each washer and measure its thickness. This will save time when selecting new elements and will help to understand the actual wear of the mechanism.
Replacing shims
To replace the washer, you must remove the pusher. This is done using a special hook or magnet, but it is better to use a special puller that allows you to gently press the pusher and remove the locking pin or the washer itself. On the motor Nissan Cube The design of the pushers allows the washer to be removed through a hole in the body.
The washer can be accessed by slightly turning the pusher. It is important not to damage the surface of the pusher, as any scratches can lead to scuffing on the camshaft. Take out the old washer, measure its exact thickness with a micrometer and compare it with the calculated one. Thickness calculation is made according to the formula: new washer = old washer + (measured gap - nominal gap).
- 🧮 Intake formula: T = A + (V - 0.20), where A is the old washer, V is the measured gap.
- 🧮 Release formula: T = A + (V - 0.30), where A is the old washer, V is the measured gap.
- ⚖️ Round the resulting value to the nearest standard puck size.
Place the new washer in place, making sure it lies flat. Check to see if the pusher is stuck. Repeat the procedure for any valves that are out of tolerance. Do not change the washers if the gap is within the normal range, so as not to once again upset the balance of the mechanism. Selection accuracy - the key to long-lasting engine operation.
☑️ Check before installing washers
Assembly and final inspection
After all the washers have been replaced, it is necessary to reassemble the engine in the reverse order. Install the valve cover, having first cleaned it of old sealant and installed a new one. Apply a thin layer of sealant to the joints of the cover and the cylinder head, avoiding getting it inside the engine. Tighten the cover bolts crosswise to the recommended torque.
Install the camshaft and crankshaft pulley, making sure all marks line up perfectly. Tension the timing chain by releasing the tensioner lock. Rotate the engine by hand a few revolutions to make sure there is no jamming and the marks match again. Valve timing must be strictly synchronized with the position of the pistons.
Connect all removed components: throttle, pipes, wiring. Start the engine and let it idle. Listen to the operation of the timing belt. The sound should be smooth, without metallic ringing or knocking. If the noise remains, there may have been errors in the calculations or the measurements were inaccurate.
| Valve type | Nominal clearance (cold) | Allowable wear | Washer material |
|---|---|---|---|
| Inlet | 0.15–0.25 mm | Up to 0.30 mm | Alloy steel |
| Outlet | 0.25–0.35 mm | Up to 0.45 mm | Heat-resistant steel |
| Pusher | — | Wears out along with the washer | Cast Iron/Steel |
| Camshaft | — | Signs of wear are not acceptable | Hardened steel |
⚠️ Attention! After replacing the washers, be sure to check the engine oil level. Air entering the lubrication system during assembly can lead to oil starvation in the first minutes of operation.
Correct assembly and alignment of timing marks is more important than perfect clearance accuracy. A timing error will destroy the engine faster than imperfect valve clearance.
Frequent errors and operating nuances
When working with a motor HR12DE Mistakes are often made when choosing the thickness of washers. Some mechanics round the values down to be on the safe side, but this can lead to overheating of the valve. Thermal gap must be strictly within tolerance, otherwise the valve will not close tightly when heated.
Another common problem is the use of low-quality sealant. Cheap compounds can soften at high temperatures and get into the oil passages, clogging the filter or oil pump. Use only original materials or high-quality analogues recommended by the manufacturer Nissan.
- ❌ Do not use washers from other models, even if the thickness is the same - the material may differ.
- ✅ Always replace the valve cover gasket when disassembling.
- ⚠️ Do not tighten the cover bolts by eye - use a torque wrench.
If after adjustment the engine continues to make noise, perhaps the problem is not in the gaps, but in the wear of the camshaft cams themselves or hydraulic tappets (if they are in the system). In such cases valve adjustment will not help, and the camshaft will need to be replaced or the cylinder head repaired.
What to do if the washer is stuck in the pusher?
Use a magnet or a special hook. Sometimes it helps to lightly tap the pushrod through a soft pad to move the washer out of place, but be careful not to damage the parts.
Cost of work and choice of service
Adjusting valves is a labor-intensive procedure that takes from 3 to 5 hours, depending on the qualifications of the technician and the condition of the components. If you are not confident in your abilities, it is better to entrust the work to professionals specializing in Japanese cars. Errors in the timing belt can cost much more than the cost of the work.
In service centers, the cost of adjustment usually includes removing and installing components, measuring gaps and selecting washers. Additional costs may arise if new gaskets, sealant or washers need to be purchased. Washer price varies depending on the manufacturer, but original parts are always preferable.
If you decide to do this yourself, consider the cost of special tools. Purchasing a micrometer and pullers can be worthwhile if you plan to service multiple vehicles. However, for a one-time operation on one Nissan Cube this may not be economically feasible.
How can I find out which washers are installed at the factory?
On some engines, the markings of the washers are applied to their end part, but most often it is necessary to measure their thickness after dismantling, since the factory markings are erased over time.
FAQ: Answers to popular questions
How often do valves on Nissan Cube AZ10 need to be adjusted?
It is recommended to check the gaps every 90,000 - 100,000 km. If you hear a metallic knock in the area of the cylinder head, a check should be carried out immediately, regardless of mileage.
Is it possible to adjust valves on a hot engine?
No, absolutely not. All measurements should be made only on a cold engine (temperature below 35°C). Metal expands when heated, and measurements on a hot motor will give false results, which will lead to incorrect assembly.
What happens if the exhaust valve clearance is too small?
If the gap is small, the valve will not close completely when heated. This will lead to burnout of the valve edge, a drop in compression and failure of the exhaust manifold. The engine will begin to lose power and consume more fuel.
Do I need to change the oil after adjusting the valves?
Preferably. When disassembling the lubrication system (removing the valve cover), some of the old oil may leak out, and microparticles of dirt may also get inside. Changing the oil will keep the engine clean after repair.
Is it difficult to select washers yourself?
This requires care and precise measurements. You need to know the exact thickness of the old washer and the measured gap to calculate the new one. If in doubt, use the selection tables or consult a specialist, as an error of 0.05 mm can be critical.