Valve adjustment <em>Nissan Almera N16</em>: a complete guide with clearance tables and common errors

Nissan Almera N16 - a car that has gained popularity due to its reliability and ease of maintenance. However, even such machines have components that require periodic attention. One of them is gas distribution mechanism, where the thermal clearances of the valves are violated over time. If left uncorrected, the consequences can range from increased fuel consumption to critical wear of the camshaft and valve guides.

This article is an analysis of the process of adjusting valves on Almera N16 with engines GA16DE (1.6 l) and QR20DE (2.0 l). We will consider in detail the necessary tools, a step-by-step algorithm, factory tolerances and typical mistakes that even experienced craftsmen make. And for those who doubt their abilities - honest analysiswhen it is better to entrust the adjustment to professionals.

Why is it important to adjust the valves Almera N16?

Thermal clearances of valves are not a whim of engineers, but critical parameter, affecting engine life. During operation, the metal expands, and if the gap is too small, the valve does not close completely. This leads to:

• 🔥 Burnout of valves (especially relevant for graduations, where temperatures are higher).
• 💨 Loss of compression — the engine loses power and starts worse when cold.
• 🛢️ Increased oil consumption due to a leak in the combustion chamber.

On the other hand, increased clearance leads to:

• 🔊 Metallic knock on a cold engine (a characteristic sign of a problem).
• ⚡ Shock loads on the camshaft cams, which accelerates their wear.
• 📉 Reduced engine efficiency — the valves do not open completely, impairing the filling of the cylinders.

On Almera N16 with a mileage of 80,000 km or more, valve adjustment becomes mandatory procedureeven if there are no symptoms. The manufacturer recommends checking the clearances every 60,000–100,000 km, but in Russian conditions (bad fuel, frequent cold starts), it is better to reduce the interval to 40,000–60,000 km.

What tools will you need?

To adjust valves on Almera N16 You don’t need exotic devices, but you can’t do without a specialized tool. Here's the full list:

Tool	Purpose	Notes
Stylus type (0.10–0.50 mm)	Measuring gaps	It’s better to take a branded one, for example, Hazet or King Tony — cheap probes often lie by ±0.02 mm.
Micrometric wrench for adjustment	Fine Gap Adjustment	For Almera N16 A wrench with a range of 8–14 mm is suitable.
Camshaft lock	Shaft blocking during adjustment	You can make it yourself from a metal plate, but a factory one is more reliable.
Torque wrench	Tightening the cylinder head cover bolts	Tightening torque - 8–10 Nm.
Valve cover remover	Removal without damaging the gasket	Optional, but simplifies the work.

Also prepare:

• 🔧 Socket wrenches at 10, 12, 14 mm.
• 🧴 Sealant for valve cover gasket (e.g. Loctite 574).
• 🧼 Carburetor Cleaner for removing carbon deposits from timing parts.
• 📐 Vernier caliper to check the thickness of the shims.

Preparing the car: step by step

Adjusting the valves Almera N16 requires accuracy and consistency. Let's start with preparation:

1. Cool the engine. You can only work on a cold engine (temperature no higher than 20–25°C). If the car has been driven, let it sit for 4-5 hours.
2. Remove the air duct and air filter housing. This will give access to the valve cover. On QR20DE Additionally, you will have to dismantle the throttle assembly.
3. Disconnect the high-voltage wires and ignition coils. Remember their location or take a photo so as not to mix them up when assembling.
4. Drain the oil (optional). If the oil is old, it is better to replace it after adjustment - during the process, dirt may get into the cylinder head.

Now remove the valve cover:

5. Unscrew the 12 bolts securing the cover (on GA16DE) or 15 bolts (per QR20DE) with a 10 mm wrench.
6. Carefully pry off the cover with a plastic spatula so as not to damage the gasket. If it is stuck, use carburetor cleaner to soften the sealant.
7. After removing the cover do not rotate the crankshaft — this can lead to contact between the pistons and the valves!

Warning: on Almera N16 with engine QR20DE Removing the cylinder head cover can cause damage oil seals. If they harden or crack, replace them immediately, otherwise after adjustment the engine will begin to “eat” oil.

Factory valve clearances: table for Almera N16

Incorrect clearances are the main reason for unsuccessful adjustment. On Almera N16 they differ depending on the engine type and temperature. Official data from Nissan:

Engine	Valve type	Clearance (cold engine)	Gap (hot engine)	Notes
GA16DE	Intake	0.25–0.35 mm	0.20–0.30 mm	Adjustable with washers
GA16DE	Graduation	0.30–0.40 mm	0.25–0.35 mm	—
QR20DE	Intake	0.20–0.30 mm	0.15–0.25 mm	Requires more precise tuning
QR20DE	Graduation	0.30–0.40 mm	0.25–0.35 mm	Sensitive to overheating

Important: clearances on Almera N16 regulated only on a cold engine. If you measure them on a hot engine, use the correction values from the table. Also keep in mind that:

• 🔹 On QR20DE Exhaust valves wear out faster - check their clearances first.
• 🔹 If the gap is outside the tolerance limits by more than 0.05 mm, the valve requires replacement or grinding in.
• 🔹 After adjustment, the gaps may “go away” by 0.01–0.02 mm - this is normal due to shrinkage of the washers.

Step-by-step adjustment instructions

Now we move on to the most important stage. Follow the algorithm strictly point by point:

1. Installing the piston of the 1st cylinder at TDC

To do this:

1. Remove the timing belt cover.
2. Turn the crankshaft clockwise using the pulley bolt (19 mm wrench) until the mark on the pulley aligns with the mark on the front cover.
3. Make sure that the camshaft cams of the 1st cylinder are facing up (the valves are closed).

⚠️ Attention: if the marks do not match, there is a risk of an error with the valve timing. In this case it is better to use crankshaft clamp or contact a specialist.

2. Measuring gaps

Take a dipstick and check the gap between the camshaft cam and the adjusting washer:

• 📏 For intake valves GA16DE dipstick 0.30 mm should go in with slight effort.
• 📏 For graduation - probe 0.35 mm.

If the probe passes too freely or does not enter at all, adjustment is required.

3. Replacing adjusting washers

Algorithm:

1. Press the valve pusher with a special tool (or carefully pry it with a screwdriver) to push it in and lock it in the lower position.
2. Remove the old washer with tweezers and measure its thickness with a micrometer.
3. Select a new washer using the formula:

   Толщина новой шайбы = Толщина старой + (Измеренный зазор — Номинальный зазор)

4. Install a new washer and check again.

Example: if the old intake valve clearance 0.40 mm (face value 0.30 mm), and the thickness of the old washer 3.50 mm, then:

Новая шайба = 3.50 + (0.40 — 0.30) = 3.60 мм

4. Check and assembly

After adjusting all the valves (remember to turn the crankshaft to access the remaining cylinders):

• 🔄 Check the gaps again - they may change after installing the cover.
• 🧴 Apply a thin layer of sealant to the valve cover gasket.
• 🔧 Tighten the cover bolts criss-cross torque wrench (torque 8–10 Nm).

What to do if there are no adjusting washers of the required thickness?

If there is no suitable washer, you can combine two thin ones, but this is a temporary solution. It is optimal to order original washers Nissan (article for GA16DE — 13211-4M500, for QR20DE — 13211-6J000).

Common mistakes and how to avoid them

Even experienced mechanics sometimes make mistakes when adjusting valves Almera N16. Here are the most common:

⚠️ Attention: If, after adjustment, the engine begins to “trouble” or a metallic knock appears, stop operating immediately! This is a sign incorrectly set gaps or foreign objects entering the cylinder head.

• 🔧 Failure to comply with the tightening torque of the cylinder head cover bolts.

  Consequences: oil leakage or deformation of the cover. Always use a torque wrench!

• 🌡️ Adjustment on a hot engine without adjusting clearances.

  On Almera N16 this leads to pinched valves after the engine cools down.

• 🔄 The crankshaft is not rotated when moving to the next cylinder.

  If the marks are not aligned, you will adjust the valves in the wrong phase.

• 🧲 Using magnetic probes.

  They may stick to metal and give inaccurate readings. Use only non-magnetic probes.

Another typical problem is mixed up washers. To avoid this, lay them out in cylinder order (for example, on a sheet of paper with numbering) and label the thickness.

When is it better to entrust the adjustment to professionals?

Although the valve adjustment is Almera N16 — a procedure accessible even to beginners; there are cases when it is better to contact the service:

• 🔍 If the engine is already knocking.

  The knocking noise can be caused not only by clearances, but also by wear on the camshaft or tappets. Diagnosis requires experience.

• 💥 After the timing belt breaks.

  In this case, the valves could be bent, and simple adjustment will not help - troubleshooting is required.

• ⚙️ If there is no specialized tool.

  Without a camshaft clamp and a micrometer, the adjustment accuracy will be low.

• 📉 In case of critical engine wear (mileage 200,000+ km).

  It may be necessary not only to adjust, but also to replace the oil seals and valve guides.

Average cost of valve adjustment per Almera N16 in the service - 3,000–5,000 rubles (excluding spare parts). If you are not confident in your abilities, it is better to pay for the work than to take risks major repairs due to an error.

FAQ: answers to frequently asked questions

Is it possible to adjust the valves Almera N16 without removing the valve cover?

No, that's impossible. To access the pushers and camshaft, the cylinder head cover must be removed. Attempts to “feel” gaps through technological holes will lead to inaccurate results.

How often do valves need to be adjusted if the car runs on gas?

On cars with LPG, valves wear out faster due to higher combustion temperatures. Recommended interval - every 30,000–40,000 km. Pay special attention to the exhaust valves: check their clearances at every maintenance.

What happens if you don't adjust the valves at all?

When systematically ignoring adjustments:

1. Compression in the cylinders will decrease (the engine will lose power).
2. Oil consumption will increase due to wear of the valve stem seals.
3. Scores will appear on the cylinder bore (due to metal particles).
4. In critical cases, the timing belt breaks and the valves “meet” the pistons (on QR20DE this leads to bending of the valves).

Can shims from other engines be used? Nissan?

Theoretically, yes, but only if their thickness and diameter match the original ones. For example, washers from Primera P12 (engine QR20DE) suitable for Almera N16 with the same motor. However, it is better to take parts with the article number indicated in the manual.

How can I check if the valves are adjusted correctly?

After adjustment:

1. Start the engine and listen to it run when cold - there should be no metallic knocking.
2. Check the compression in the cylinders (standard for Almera N16 — 12–14 bar).
3. Evaluate fuel consumption and oil consumption (if they were increased before adjustment, they should return to normal after).

If the knocking noise remains, it means that the gaps are tight or, conversely, too large. Repeat the adjustment.