Toyota has replaced the 1.4-liter VVT-i engine in their Auris with a new, smaller, and more efficient Dual VVT – I drivetrain. This means that it produces power just as effectively yet is less fuel-thirsty than before while also weighing down its four-wheeled siblings.
We are talking about the 1NR-FE and its eventual reincarnation in which are bound to in the Asian market, particularly in China. If you are not that aware, the Toyota 1NR is 36% lighter due to thinner pistons. Among other improvements made by Toyota engineers, overtime for this reworked motor design has affected the development and overall success of the engine.
The reason we talked about the 1NR-FE is that the 6NR-FE engine is based on the 1NR-FE engine. It has the exact features, and their only difference is that the Chinese variant is going somewhere in Asia. Other than that, you cannot spot anything different.
So let’s go and talk about these modified 1NR-FE engines, also known as the 6NR-FE engine.
What are Toyota 6NR-FE Engines?
The Daihatsu department was given priority in developing and manufacturing new small-displacement series, and NR engines are part of this development. However, the NR engines are best recognized as Toyota model engines, contrary to the Daihatsu badge.
The first engine of the series, the 1NR-FE, was released in 2008 for the European market. It instantly replaced the obsolete 4ZZ-FE and then progressively superseded the 2NZ-FE and 2SZ-FE in the Japanese market.
The 1NR-FE, as it progressed, became the base engine as the sole basis of the upcoming NR engines. Most of the models laid out and released succeeding the 1NR carry the same features, technology, and other details.
The 6NR-FE, if you will, bears the same engine as the 1NR.
In addition, and generally, the NR series has aluminum engine blocks and DOHC cylinder heads. It also employs multi-point or direct fuel injection and has four valves per cylinder.
Dual VVT-i is standard on the 1NR, 2NR, 3NR, 4NR, 5NR, 6NR, and 7NR engines, while VVT-i is standard on the 8NR or the FTS engine, allowing it to function in both the Otto and modified-Atkinson cycles to increase thermal efficiency.
Engine Specifications and Design:
- Production Run: 2014 – Present
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Aluminum
- Configuration: Inline 4
- Bore: 72.5 mm
- Stroke: 80.5 mm
- Valvetrain: DOHC four valves per cylinder
- Displacement: 1.3 L (1329 cc)
- Compression Ratio: 11.5
- Weight: 190 lbs.
- Maximum HP: 99 HP at 6,000 RPM
- Maximum Torque: 123 lb-ft at 4,200 RPM
The 6NR-FE is based on the 1NR-FE engine, which is a four-cylinder inline engine with dual VVT-i and Stop & Start. The Yaris XP9F was released in Europe in late 2008, with the primary objective of enhancing engine performance while cutting emissions and fuel consumption.
These 6NR-FE engines retain the same technology and features as the 1NR-FE.
The cylinder block is intended for lightweight engines with high compression ratios. The aluminum “open deck” with thin cast-iron liners functions as a single sturdy component, delivering strength and power that will endure until the engine is rebuilt.
Because the wall thickness between each of these cylinders is only 7 mm, you won’t have to worry about reboring your engine if something goes wrong – you’ll be ready to go straight away.
The axis of the crankshaft has been shifted by 8 mm relative to the cylinder axis lines, lessening the lateral component of the piston’s force imposed on the cylinder wall and reducing wear. The crankshaft has four balancing weights, shorter journals, and separate main bearing covers.
The high-rise spacer is a revolutionary design that allows for more intensive coolant circulation near the top of each cylinder, which improves heat dissipation and helps even out thermally generated load.
The camshafts are separate and complex unit that houses the valves. The housing on this side simplifies the design of cylinder heads because it only needs to be machined for two positions instead as opposed to having three or four different types.
You could use these depending upon the needs- which makes production easier but also means there’s less room inside your engine if something goes wrong with one part.
But what really sets these apart is how they work, hydraulic lash adjusters allow sudden adjustments when needed; roller rockers make sure every note sounds just right by giving more precise timing than old-style adjustable tappets do abroad in Asia markets, which isn’t surprising considering the region opt for older styles.
Advancements of the 1NR to the 6NR
Not only that the 6NR-FE engines benefitted from the advancements of the 1NR-FE, but they also adapted its strong features, including pistons and some other detailed work done for the 1NR-FE.
Since we mentioned it, advanced engineering has been applied throughout the engine. Toyota engineers streamlined the intake channel within the engine, improved airflow through computer modeling, flattened all surfaces to decrease turbulence, and rounded all curves and rough edges.
One of the most essential aspects of the 1NR-FE engine is the piston design. These pistons are also placed in the 6NR engines and shipped to Chinese markets too.
The thing is that they have a smaller contact area and utilize carbon ceramide, a complex material used in Formula One engineering, to reduce friction. They are more compact and lighter than the preceding 1.3 L model. The engine incorporates cooled exhaust gas recirculation to reduce pumping losses and NOx emissions.
Pistons are made of aluminum alloy with a cut skirt and a tiny T-shaped protrusion. The top compression ring groove is anodized, and the upper compression ring’s edge and oil scraper have an anti-wear PVD coating.
The pistons are not floating, and they are press-fitted into the connecting rod. Toyota officially restricts this process for 1NR engines and 2NR engines as well, neither can be re-used if you take them apart even in a specific way that’s been approved by the automaker.
Application of the 6NR-FE engine:
- Toyota Yaris XP150 Chinese Market Only
Problems Surrounding Toyota 6NR-FE Engines
Amidst some noise in the car community, the 6NR-FE cannot be stopped. With its durability and economy, the Toyota 6NR-FE engine is a different engine from its peers. Though it bears the 1NR-FE badge, it created a name of its own – independent, reliable, and strong.
However, like any other piece of equipment, it has flaws that must be addressed in order to avoid difficulties in the future. Let’s take a look at some of the most common worries about the Chinese equivalent of the 1NR-FE.
Because the majority of the faults are shared by all NR engines, some of the issues below can be seen in other NR engines. The following are a few examples:
1. Excessive Soot Deposits
The following section outlines a problem with some autos. It has been discovered that they take longer than normal due not just to the increased time required for ignition but also to residue buildup within specific components such as pistons.
Excess soot deposits in the combustion chamber, valves, and valve seats can cause compression to be reduced, as this was the case across all NR engines. This causes the engine to take longer to start, resulting in the display of DTC P1604.
The problem is recognized by TSB EG-00037T-TME as an excessive deposit of this type, which may cause a reduction or loss of power.
2. Excessive Oil Consumption
The most well-known and common problem with NR engines, not only the 6NR-FE, is high oil consumption, which generally presents itself at less than 60,000 miles. According to Toyota’s usual explanation, the piston rings are trapped.
Although cylinder block reboring is not required, the need to replace pistons and connecting rods at the same time prevents a low-cost engine renewal.
In TSB EG-0095T-1112, oil usage was noted as a source of concern. Early in 2016, production changes were implemented, such as revised rings and pistons with connecting rods, as well as valve cover replacement for those with greasy valves or nozzles.
3. Clattering noise from the Timing Chain area
Another issue that you might need to magnify is the foreign noise in the timing chain are. Well, you may have heard the grinding or clanking sound of your timing chain, which can be an indicator that it needs to be replaced. This is detailed in TSB EG-00039T – Toyota’s technical service bulletin for this issue.
There are two options available; either do nothing or just replace one part by installing a new tensioner arm on top of their already installed engine block without changing any other parts.
4. Rattling or Knocking Noise During Operation
During engine operation, large deposits in the combustion chamber cause a rattling or banging noise. This problem is acknowledged and explained in TSB EG-0094T-0714, which describes some production adjustments introduced at the beginning of 2014 to fix it for good.
The engine’s performance can be dramatically improved with this part’s new, more customized variant. You’ll also want to get your hands on ECU firmware that has been reprogrammed for increased gas mileage and power output.
The Toyota 6NR-FE engine is the perfect choice for those looking to have some fun on their way through town. It was made with this type of purpose in mind, so it’s great that you’ve found yourself among this engine.
Generally speaking, though, Asian bound or any regional-based cars are focused more towards driving around cities rather than being used as country transportation. The engine capacity is lower but still powerful and efficient VVTi drivetrain produces just as much power while using less gas than before.
Add in the great fuel economy, and you’ll never regret owning this dependable little gem of car gear. The Toyota NR is a perfect fit for those who want the best of both worlds: great fuel economy and dependability. These characteristics are combined into one little package; the new generation Toyota NR is unbeatable.
With its low fuel consumption, this affordable and dependable engine will get you anywhere. It has no major problems, making it a good choice for anybody wishing to save money on vehicle payments or just get around town more efficiently.