Renault engines of the K family
K7M
- one of the most reliable and unpretentious motors with a long service life. It is still installed on the simplest versions of Renault Logan and Sandero cars. A small displacement of 1.6 liters, an eight-valve design and extremely low boost - power 82-87 hp, provided it with a service life of up to 400,000 km and sometimes even more than that. The cylinder block is cast iron, the piston group design is oil-resistant. Good resistance to slight overheating. When using high-quality consumables, timely installation of good components such as a timing belt with rollers, a coolant pump and timely adjustment of the valves, the engine shows miracles of reliability.
is a more modern, powerful, 16-valve version of the same engine. It is installed on many Renault cars - Logan, Sandero, including Stepway versions, Megane, Lodgy, Clio, Scenic. Until recently, it was also used on the Lada Largus car. The power of different modifications is 102–108 hp. The amount is quite tax-inefficient.
The motor requires minimal maintenance thanks to hydraulic compensators in the valve drive. The reliability of the unit is almost as good as the low-power 8-valve version.
Mercedes M266 (1.5 / 1.7 / 2.0)
Production: 2004-2012.
Application: Mercedes A-Class (W/C 169), Mercedes B-Class (T 245).
Durable and reliable diesel engines from OM601 to OM606 are known from the legendary W124. But they have long been outdated. However, even among newer units you can find a durable motor. This is M266. The 4-cylinder petrol engine is an evolution of the previous M166, known from the first A-Class and Vaneo.
The engine received a specific design, since it had to be placed at a large angle in a cramped engine compartment. The engineers relied on simplicity: only one timing chain and an 8-valve timing mechanism.
The mechanical part is very reliable. Injector malfunctions are very rare (somewhat surprising for a gasoline engine with indirect injection). But in most cases, the defect appeared during the warranty period.
All three versions of the motor are very durable. The presence of turbocharging for A200 Turbo modifications theoretically increases the likelihood of malfunctions, but in reality nothing like this happens. The disadvantages include slightly increased fuel consumption, but this is due to the insufficiently good aerodynamics of the body.
Cast iron block or at least sleeves: which modern cars still have them?
“I recently found out that the 2022 Toyota Camry. a 2.5 liter petrol engine (code 2AR-FE) with an aluminum cylinder block and cast iron liners is installed. I thought that engines with a cast-iron cylinder block or at least with cast-iron liners are practically no longer produced. I would like to know which other modern car manufacturers use similar engines, and on which models they are installed.”
Not so long ago we already answered the question about “cast iron” engines, however, in the “state sector” segment. And then they mentioned, for example, Renault engines: the 8-valve K7M and 16-valve K4M with a volume of 1.6 liters have a cast iron block. Yes, they are a hundred years old, they remained in production only for the sake of budget models (primarily the “Loganov” family) only in the markets of developing countries. After all, European Dacia Logan & Co are already fully equipped with 0.9T turbocharged engines. And in our region, the 16-valve engine is giving way to the more modern Nissan HR16DE with an aluminum block, the production of which is established in Togliatti. But the 8-valve K7M is still in service. The same applies to the 2.0-liter F4R, which is installed on the Duster and Kaptur.
VAZ engines also have a cast iron block. And not only the 8- and 16-valve (VAZ-21116 and VAZ-21126, respectively) 1.6-liter versions, which have been produced for several years now, and which are equipped with modern Lada models. The new VAZ-21179 with a volume of 1.8 liters and a power of 122 hp, which is now installed on Vesta and XRay, was built on the basis of the latter engine. The engine has different pistons, a crankshaft, an improved cooling system, and is also equipped with variable intake valve timing, but the block is still cast iron.
At the same time, the engine has a complex design, including a number of interesting technical solutions. Thus, to optimize the temperature regime, a split cooling system with two thermostats is used. An exhaust manifold integrated into the cylinder head reduces exhaust gas temperatures, optimizing engine performance over a wide speed range. To reduce the vibration load of the three-cylinder engine, a new balancing scheme has been used, and a low-friction timing belt in oil mist with a dynamic tensioner is designed to make the engine very quiet. To ensure “immediate” thrust even from low revs, a low-inertia Continental turbine and a system of independently variable intake and exhaust timing are used, and direct fuel injection is also used. Despite all the “sophistication” and a fairly high degree of boost, the engine turned out to be quite reliable and durable.
Opel also has a modern engine with a cast iron cylinder block. This is the 1.6 SIDI (A16XHT/A16SHT), which was released in 2013. It can be found on Astra and Insignia models in 170 and 200 hp versions. The engine is equipped with a Garrett turbine, direct fuel injection, balancer shafts, variable valve timing and a timing chain drive. By the way, older 1.6 (Z16XER/A16XER) and 1.8 (Z18XER/A18XER) naturally-aspirated engines, which until recently were installed on almost the entire Opel passenger model range, also have a cast-iron block.
The current Subaru engines can be called relatively modern: the FB family was introduced in 2010. Considering that the previous EJ family remained in production for more than 20 years, it can be assumed that the current Japanese boxers will remain in the Subaru lineup for a long time. Like its predecessors, the cylinder block is cast from aluminum, but the liners are cast iron.
Of course, we did not talk about all manufacturers and modifications of engines with a cast iron block or liners. But the examples given clearly demonstrate that engineers are in no hurry to completely abandon heavy metal, even in the case of very “advanced” motors. From the point of view of the resource of the hardware itself, this is certainly not bad. But once again go through the list of these motors: many of them are not considered problem-free, since there are enough serious reliability problems in other components and systems.
Subaru 3.0/3.6 R6 (EZ30/EZ36)
Production: since 2000.
Application: Subaru Legacy, Subaru Outback, Subaru Tribeca.
Of all the famous boxer engines of Subaru, the most reliable are the naturally aspirated six-cylinder EZ series, known for the Outback, Legacy 3.0R and the Tribeca crossover. The first versions of the 3-liter engines for the Outback H6 (219 hp until 2002) still had a mechanical throttle control drive and an aluminum intake manifold. Later modifications (245 hp), despite more complex technologies (among others, a system for adjusting the lift height and phases of the intake valves, and in the 3.6 also the exhaust valves), did not become more “vulnerable”.
The engine has so-called wet cylinder liners and a durable timing chain. The only real drawback is the relatively high level of fuel consumption (especially in the Legacy 3.0 Spec B, equipped with a sports manual transmission with a short-throw gear selector) and minor difficulties during maintenance (for example, to replace spark plugs due to poor accessibility to the “horizontally” located cylinders).
Renault and Nissan
Two engines are considered one of the most reliable. This is a K4M with a displacement of 1.6 liters and a power of 102-105 hp. s., as well as a 2.0-liter F4R, which develops power of 135-143 hp. With. These power units are installed on mass models such as Renault Logan, Sandero, Duster, Lada Largus and Nissan Almera. A two-liter engine powers Renault Duster and Kaptur, as well as Nissan Terrano. All of them are distinguished by their simplicity of design. The engines have a cast-iron cylinder block, a low boost level, and hydraulic compensators in the valve drive. All these components are quite reliable and, with timely care and moderate operation, can travel half a million kilometers.
VM R425 DOHC
VM R425 DOHC is perhaps the most reliable modern diesel engine in the world. It has a two-shaft design. There are four valves per cylinder. The engine is usually equipped with a turbine and has a volume of 2.5 liters. And its power can reach 143 horsepower. The power unit has a long history. It has undergone various changes many times, and the famous engine was created by the Italian company VM Motori. It can be found on cars mainly of American brands such as Dodge, Jeep or Chrysler. With proper maintenance, an engine can last at least three years without any problems, but provided that the car is in the same hands all this time. Buying a used car with such an engine is a pig in a poke, requiring serious professional diagnostics and careful choice.
Now there is a 2.8-liter version of this power unit. It is called R428 DOHC. The power of such an engine is 150-180 horsepower. And you can find it, for example, on such American cars as Chrysler Voyager and Chrysler Grand Voyager.
Honda 2.2 i-DTEC
Production: 2008-2015.
Application: Honda Accord 8th generation, Honda CR-V 3rd generation, Honda Civic – 9th generation.
In fact, you could list 98% of Honda's petrol units here and no one would object. But much more interesting is the fact that the Japanese diesel engine turned out to be very reliable. And this despite the fact that its design uses all the most vulnerable elements of modern diesel engines, which the best competitors cannot cope with.
The use of a single-row timing chain is completely counterproductive, not to mention the thermally unstable aluminum block with thin, dry steel cylinder inserts (complicating heat dissipation) - any BMW N47 diesel connoisseur will tell you.
In 2.2 i-DTEC, such a set works properly for a long time. Even piezoelectric injectors, a turbocharger (has water-cooled bearings) and an electrically controlled EGR valve do not cause problems. The typically carbon-encrusted swirl flaps in the intake manifold were replaced with a bypass valve at the entrance to the split intake tract, and the EGR was “plugged in” behind it.
The only known drawback is the failure of the DPF differential pressure sensor.
Cast iron engines warmed up faster
As a rule, the manufacturer does not indicate a warm-up period, because the newer the engine model, the more time is spent on this process. The reason lies in thermal conductivity and heat capacity.
Cast iron wins in both respects: by retaining heat inside, it spends less energy heating the block. Having compared the thermal characteristics of the materials, it becomes clear that the cast iron block of the internal combustion engine has better warm-up time, suppressing noise and vibration that appears during a cold start.
However, there is also a downside to the coin: an engine made of this material is more difficult to cool when reaching power mode. True, the aluminum block also suffers from cooling problems - this material is less resistant to overheating, and electronic thermostats and even the latest antifreezes are not always able to provide the proper temperature at the right time.
Separately, it is worth mentioning good interior heating in cars with a cast-iron engine, because the rate of temperature increase directly depends on the heating of the coolant.
Toyota 1.5 1NZ-FXE Hybrid
Production: since 1997.
Application: Toyota Prius I, Toyota Prius II, Toyota Yaris III Hybrid.
As in the case of Honda, almost all Toyota engines could be included in this review, but we will focus on the hybrid, which most motorists still perceive with skepticism. And this despite the fact that this power unit has unprecedented reliability. A simple high compression gasoline engine running on the Atkinson cycle, a permanent magnet synchronous electric motor and nothing more.
There is no gearbox in the classical sense, and therefore problems with this device disappear. Instead, a planetary gearbox with two inputs and one output is used. The gear ratio changes depending on the difference in rotational speeds of both engines.
What scares me the most is the expensive battery. But so far none of the owners have changed it. European competitors cannot compete with the phenomenal Japanese reliability.
Why are aluminum motors better than cast iron ones and is this true?
Currently, on the Russian market it is quite difficult to find car models equipped with engines whose cylinder block is made of cast iron.
They have long been replaced by models of modern cars with an aluminum power unit. According to manufacturers, such engines are more modern and durable. But many drivers wonder whether this is really so, given the frequency of failure of new engines.
Advantages of an aluminum motor. Of course, such a motor has less mass, which has a positive effect on dynamic parameters, technical characteristics, and so on. The aluminum cylinder block is less susceptible to corrosion and, thanks to better thermal conductivity, it warms up and cools down faster.
Manufacturers do not hide that the frequency of repair work with such engines is directly related to improper operation, which is neglected by most drivers. The thing is that motorists do not carry out the necessary maintenance in a timely manner, independently allowing serious engine breakdowns to occur.
The disadvantages of an aluminum unit are that when heated, this material expands more than cast iron, and repairing such an engine is much more difficult and more expensive than a cast iron one, if possible at all. Sometimes the performance of an aluminum block cannot be restored because the necessary parts are simply not produced for it.
In addition, the cost of spare aluminum motors on the market is significantly higher compared to cast iron models. Drivers must understand that the cost of possible repairs will depend on their responsibility, which, in principle, can be quite easily avoided by paying attention to the car during operation.
Old engines are easier to manufacture
The production of an engine from less durable materials dictates more stringent requirements for the accuracy of the process, as well as the use of expensive related materials. It is not difficult to guess that the equipment of the production line, the training of specialists and the hard work of the design bureau also introduces considerable costs into the manufacturer’s bills.
In the old days, everything was somewhat different - the engine was initially designed for lower requirements for the technological process, the properties of the material forgave minor errors and errors, and commonly used equipment was used in production. The latter is confirmed by the practice of repairs both in small workshops and in garage conditions by various craftsmen. All this significantly reduced production costs, inversely affecting reliability. In our time, there has been a reversal of this trend.
It can be assumed that a new machine can be modified to increase its service life. Alas, in our time there is such an aspect as programmable aging, which has not been ignored by automakers, introducing complicated components from cheaper materials that are essentially disposable.
The purpose of this measure is quite simple - to push the owner to buy a new car, reducing the reliability of the products. Therefore, repairing a modern car is financially unprofitable, and modernization is impossible due to the lack of safety margin.
Cast iron is stronger than aluminum
Cast iron has higher durability and strength compared to any aluminum alloy. We can conclude that a car with a cast iron block will be able to travel a greater distance than with an aluminum one. Based on the experience of motorists: half a million kilometers is a real mileage, and this is far from the limit.
Aluminum, on the other hand, is a softer metal, and when the piston group operates, the cylinder walls quickly wear out, unable to withstand the loads. For this reason, in order to avoid rapid wear, a solution was found: to treat the surface of the liners with a special silicon coating called “Nikasil” and “Alyusil”, the mention of which will cause a storm of negative emotions from drivers of new cars and the opposite reaction from car service owners.
However, this did not become a panacea for premature wear: during operation, the composition eats into the wall of the liner. The durability of such a coating is questionable - 100-150 thousand km, and updating the coating is very expensive, therefore, when undergoing repairs, the block is still sleeved, which is not much cheaper.
Stages of cylinder block repair
Below are the main stages of repairing such a unit. This is what the block looks like ready for the installation of sleeves. It can be seen that three sleeves on the left are already inserted, but the fourth is not yet:
This is what a bored cylinder looks like up close. The collar for the sleeve with the upper stop is visible from above:
Aluminum lock cylinder bored
And this is what the sleeve itself looks like with the upper stop:
This is what the sleeves look like when installed in the block:
Aluminum block sleeve inserted
"Disposable" motors
There is a popular argument on the Internet that current cars are “disposable”; drive them for five years and throw them away. The popular Hyundai Solaris and its “aluminum” engine are often cited as an example. Is it true that modern engines do not lend themselves to capitalization?
“Cast iron” past...
Those who have experience driving a Zhiguli are well familiar with the term “capital car”. Its purpose is to preserve one of the most expensive elements of the engine - the cylinder block.
Since Soviet times, engine overhaul has been understood as restoring worn-out cylinders by boring them to repair size (or replacing liners). After this, pistons of the appropriate repair size are installed - such spare parts are made quite officially by the manufacturer itself. Some engines had 4-5 repair sizes, that is, they could be rejuvenated multiple times.
Previously, the most popular material for a cylinder block was cast iron: the material is heavy, but quite hard and amenable to boring. Problems began when manufacturers began switching en masse to aluminum cylinder blocks to reduce weight.
... and the “aluminum” present
Aluminum is much less wear-resistant; moreover, when rubbing against an aluminum block, aluminum pistons can “seize” - the plastic material is, as it were, “smeared” onto the rubbing surface. Therefore, engineers try to eliminate friction between the aluminum alloy and similar ones.
In addition to covering the pistons, almost always the cylinder surface of the aluminum block is insulated from the piston in some way. For example, due to a “wet” cast iron sleeve: such a sleeve is inserted into the block and washed from the outside with coolant, hence the name. The design with “wet” liners is quite repairable, since the block can be unlined and worn out liners and pistons can be replaced. However, this scheme also has disadvantages, for example, less rigidity of the block and worse vibration-acoustic characteristics (for modern engines these are important).
Is it necessary to liner all cylinders?
Sometimes the question arises: is it necessary to line all cylinders? Is it possible to get by with repairing just one cylinder?
There is only one universal answer here - “depending on the situation.” If only one cylinder has suffered critical wear, of course, it makes sense to use only its liner, this is quite acceptable. However, it must be taken into account that when lining, adjacent cylinders may receive some deformation (ellipse), and in this case it may be necessary to machine them afterwards to compensate for this deformation. But here the final decision is made individually in each specific case.
