Engine Renault K7M 710/800 1.6 8V

Renault Logan 1.6 engine characteristics

Manufactured by Automobile Dacia
Years of production - K7M 710 (2004 - 2010), K7M 800 (2010 - present)
Make \\ Engine type Renault Logan - K7M
Cylinder block material - cast iron
Power system - injector
Type - in-line
Number of cylinders - 4
Valves per cylinder - 2
Piston stroke - 80.5 mm
Cylinder diameter - 79.5 mm
Compression ratio - 9.5
Engine capacity - 1598 cm3.
Power - 86 hp /5500 rpm
Torque - 128Nm / 3000 rpm
Fuel - 92
Environmental standards - Euro 3
Fuel consumption — city 10 l. | track 5.8 l. | mixed 7.2 l/100 km
Oil consumption - up to 0.5 l / 1000 km
Engine oil Renault Logan:
5W-40
5W-30
Oil change every 7500 km.

Motor resource of the Logan 1.6 engine:
1. According to the plant - 400 thousand (unofficially, according to the tests of the plant)
2. In practice - 400+ thousand km

TUNING
Potential - unknown
Without loss of resource - unknown

The engine was installed on:
Renault Logan
Renault Sandero
Lada Largus

Faults and engine repair Renault Logan / Sandero 1.6 K7M

Engine Renault Logan K7M 710 1.6 l. 86 HP nothing more than a regular K7J 1.4 liter, only with an increased piston stroke (from 70 to 80.5 mm), of course, the height of the block slightly increased, the clutch had a larger diameter, the flywheel increased and the shape of the gearbox housing changed. Structurally, the Logan 1.6 liter engine, like its low-volume counterpart, has the same archaic design of the middle of the last century with rocker arms and a strange oil pump drive system from lower-mounted Renault engines of the 60s. In spite of everything, with a careful attitude to the engine, service and maintenance, oil changes 2 times more often than according to the instructions, it is very, very reliable, according to in-plant data, the Logan 1.6 engine life is about 400 thousand km, in practice the engine drove a little more .
In 2010, the K7M 710 was replaced with the K7M 800, the motor was strangled, pulled up to the Euro-4 environmental standard, the power decreased to 83 hp, there were no design changes.
The disadvantages of the K7M are the same as those of the K7J 1.4 engine, high fuel consumption, often at idle speed starts to float, constantly (once every 20-30 thousand km) you need to adjust the valves, there were no hydraulic compensators, timing drive belt, when the belt breaks at Logan 1.6, the valve bends, so we change the belt every 60 thousand km. All the same leaks of the crankshaft oil seal. The motor is noisy and vibrates. According to the design of the Renault Logan 1.6 engine and where the engine number is located, the information is set out in the article "motor K7J“, which, apart from the volume and related changes, has no other changes. It also describes all the faults and their causes. Speaking about which Renault Logan engine is better than 1.4 or 1.6 8 valve, take 1.6 ... the engine is the same, but the low-volume engine is very weak.
An engine was also created on the basis of the K7M K4M with a 16 valve cylinder head and other significant innovations, the power of such a motor is much higher and if you choose (for example, Logan, Sandero), always take it, you will not regret it.

Engine tuning Renault Logan K7M 1.6

Chip tuning engine Renault Logan

Logan K7M 800 engine, you can remove the catalyst, restore its original power of 86 hp, put the exhaust and flash the sport firmware, maybe add a couple more horses, but nothing will change significantly, except for fuel consumption, now your engine will eat more))

Compressor and turbine for Logan 1.6

The installation of a turbocharger and a compressor is described using the example of a 1.4 liter engine, and all this is 1 in 1 applicable to 1.6 liters. Engine power Logan 1.6 will be an average of 5-10 hp. more with the same approach. Looking ahead ... you will not be able to achieve great power.

Today we’ll talk about the Renault Logan 2 engine, discuss the pros, cons and features of ICE repair. So, in the new Logan 2, Renault offers three engines for installation:

• 8-valve engine with a volume of 1.6 liters. and power 82 HP- model K7M
• 16 valve engine with a volume of 1.6 liters. and power 102 HP- model K4M
• new 16 valve engine with a volume of 1.6 liters. and power 113 HP — H4M

Consider the pros, cons and maintainability of these engines in more detail.

• Engine Model - K7M
• Working volume - 1598 cm3
• Number of cylinders - 4
• Number of valves - 16
• Cylinder diameter - 79.5 mm
• Piston stroke - 80.5 mm
• HP power – 82 at 5000 rpm
• Power kW - 60.5 at 5000 rpm
• Torque - 134 Nm at 2800 rpm
• Compression ratio - 9.5
• Timing drive - belt
• Fuel consumption in the city - 9.8 liters
• Combined fuel consumption - 7.2 liters

Advantages of the K7M engine

• and reliability of engine design;
• reliability: proven motor resource is more than 400 thousand km;
• universal and maintainable;
• easy to maintain;
• have high torque
• good “elasticity” of engines equal to 1.83 is provided.

Cons of the K7M engine

• relatively high fuel consumption;
• there is an instability of revolutions when idling;
• there are no hydraulic compensators in the design, so it is necessary to constantly adjust the valves (after 20-30 thousand km);
• there is a possibility of bending the valves in the event of a sudden break in the timing belt;
• crankshaft oil seals often leak;
• low reliability;
• very noisy and prone to vibrations.

K7M Engine Repair

The video below shows how a typical K7M engine repair is carried out on Logan.

K4M - Renault Logan 1.6 liter engine. 16-valve 102 hp

• Engine Model - K4M
• Working volume - 1598 cm3
• Number of cylinders - 4
• Number of valves - 16
• Cylinder diameter - 79.5 mm
• Piston stroke - 80.5 mm
• HP power – 102 at 5750 rpm
• Power kW - 75 at 5750 rpm
• Torque - 145 Nm at 3750 rpm
• Engine power system - distributed injection with electronic control
• Compression ratio - 9.8
• Timing drive - belt
• Maximum speed - 180 kilometers per hour
• Acceleration to the first hundred - 10.5 seconds
• Fuel consumption in the city - 9.4 liters
• Combined fuel consumption - 7.1 liters
• Fuel consumption on the highway - 5.8 liters

Advantages of the K4M engine

• reliability, practical resource exceeds;
• compliance with Euro-4 environmental standards;
• increased power (102 hp);
• low noise and vibration resistance;
• more modern and reliable cooling system.

Compared to 8-valve engines, the K4M 16V is much quieter, not subject to vibrations and has the same resource, but much more power and torque.

Cons of the K4M engine

• expensive spare parts;
• "Bending" of the valves when the belt breaks;
• weak "elasticity" of the engine, equal to 1.53, as a result - problems with car acceleration when overtaking.

K4M Engine Repair

The video below shows how a typical K4M engine repair is carried out on Logan.

H4MK - Renault Logan 1.6 liter engine. 8-valve 113 hp

In 2104, Renault Logan 2 of the Togliatti assembly began to install a new 16-valve 1.6-liter engine. Atmospheric H4M engine(or HR16 according to the Nissan classification) has a power of 113 hp. and is also installed on Renault Duster, Captur, Lada X-Ray, Nissan Sentra and Nissan Zhuk.

It differs from the engine of the previous generation K 4M (volume 1.6 liters, power 102 hp) with increased torque (152 versus 145 Nm), but the maximum torque is reached at 4000 rpm instead of 3750 rpm. Built into the new Renault Logan 2 engine variable valve timing system, and instead of a timing belt, a timing chain finally appeared. In addition, the final drive ratio has been reduced: from 4.07: 1 for Logan and Sandero.

• Engine Model - H4M
• Working volume - 1598 cm3
• Number of cylinders - 4
• Number of valves - 16
• Cylinder diameter - 78 mm
• Stroke - 83.6 mm
• HP power - 114 at 6000 rpm
• Power kW - 83.8 at 6000 rpm
• Torque - 142 Nm at 4000 rpm
• Engine power system - distributed injection with electronic control
• Compression ratio - 10.7
• Timing Drive - Chain
• Maximum speed - 172 kilometers per hour
• Acceleration to the first hundred - 11.9 seconds
• Fuel consumption in the city - 8.9 liters
• Combined fuel consumption - 6.4 liters
• Fuel consumption on the highway - 5.5 liters

Advantages of the H4M motor

The main advantage of the new motor was improved elasticity and increased traction at low revs. But there is no increase in driving dynamics at all. Top speed increased by only 2 km/h (172 km/h). But the fuel consumption of the new Logan in the combined cycle reduced from 7.1 to 6.4 liters. per 100 km.

Cons of the H4M motor

Sedans and hatchbacks with the new engine will only be offered with a manual transmission. Modifications with a four-speed "automatic" will continue to equip the old K4M engine Spanish production, although the extra power would be better combined with an automatic. It would be logical to appear with a new engine and CVT, like the Kaptur crossover, but so far this is not even in the plans.

H4M Engine Repair

Applicability on cars

Budget car models Renault Logan 1.4 and Logan 1.6 for almost a decade of presence on Russian roads have managed to win the recognition of many thousands of motorists. The concept of the French manufacturer, which decided back in 1998 to create an inexpensive and practical passenger car designed for emerging markets, received the most triumphant continuation and unexpected development in Russia.

If in 2005 it all started on a small site of the Avtoframos enterprise in Moscow with a “screwdriver” assembly of several thousand cars a month, today the Volga Automobile Plant is already building its annual plans based on a whole “Logan” model scattering: Renault Logan, Renault Sandero, Lada Largus. Sales of these three models in the country in 2014 exceeded 160 thousand pieces.

To a large extent, such popularity of these Renault models was ensured by the use of proven and well-proven single-shaft internal combustion engines (ICE) of the K7J 1.4 l and K7M 1.6 l series as power units. The flagship of the line for Renault Logan, it is customary to consider a 16V four-cylinder liquid-cooled unit with the K4M index, the production of which, in addition to the parent company Renault Espana. It was also mastered at AvtoVAZ production sites. This 16-cap engine with decent technical characteristics is still equipped with other Renault models (Sandero, Duster, Kangoo, Megane, Fluence), as well as Lada Largus and Nissan Almera G11.

Design features and specifications of internal combustion engines

Engine design K7J (manufacturer Automobile Dacia, Romania) 1.4 l / 75 hp inherited from fairly old Renault Corporation engines of the 80s (ExJ series) and therefore looks somewhat archaic: here is an unusual oil pump chain drive used on units with lower camshafts, and ancient timing rocker arms.

The remaining solutions of the 1.4 engine are standard and do not differ in any way from other four-stroke 4-cylinder single-shaft engines of the SOHC type: the cylinder arrangement is in-line vertical, 2 valves per cylinder, timing drive from a toothed belt, liquid cooling and a combined lubrication system (lubrication is supplied to the most loaded parts of the internal combustion engine under pressure, to all others - by simple spraying). K7J is more than 400 thousand kilometers. Motor 1.4 provides the car with the following dynamics: the maximum speed is 162 km / h, it is gaining a hundred in 13 seconds.

Renault Logan K7M 710 engine and its successor K7M 800 (manufactured by the same Automobile Dacia) 1.6 l and 86 hp. (K7M 800 - 82 hp) are almost identical in design to the K7J, they also have, but they have a piston stroke increased by 10.5 mm, obtained by changing the height of the block.

A different clutch and flywheel (larger diameter) are also used, and the gearbox housing has minor reshaping. Resource K7M also exceeds 400 thousand km in mileage. Dynamic characteristics of the motor: speed at a maximum of 172 km / h, 100 km / h - in 11.9 sec unlike 1.4.

The greatest differences in design and performance are observed in the K4M engine, despite the fact that this ICE is 1.6 l and 102 hp. is also just another development of the K7M series. All-new 16-valve cylinder head with two lightweight camshafts and a new piston system. Here, finally, the need for constant adjustment of the internal combustion engine valves through fairly short runs is eliminated, eliminated by the simple use of well-known hydraulic compensators.

The motor accelerates the car to 100 km / h in 10.5 seconds, reaching a maximum of 180 km - not bad performance. There are no frankly weak points in this unit: the necessary changes have been made to the system in terms of the pump and thermostat, and the ignition module has also undergone refinement.

Advantages and disadvantages of power units

Thus, a detailed analysis of the technical characteristics of all three ICE models, as well as practical experience in operating Renault Logan with these power plants, allows you to decide which engine is better. The more powerful Renault Logan 2 1.6 liter liquid-cooled engine is still somewhat preferable to its “big brother” 1.4 liter. Power 75 hp just not enough for comfortable driving a loaded car, neither on a country road, nor in short "rushes".

And in the dispute between a 16V motor and an 8V motor, the undisputed leader is the first sample. The only characteristic in which 16V loses to its opponent is "elasticity". For the rest of the same characteristics, 16V is better better. Renault's liquid-cooled V16 engine is simply much more modern and gives more options to the driver.

The K7M engine is a power unit manufactured by Renault, designed for installation in passenger cars. After the acquisition by Renault of the domestic AvtoVAZ, engines began to be installed on many vehicles of a Russian manufacturer.

Specifications

Service

Recommended is 15,000 km. To increase the life of the motor, it is recommended to reduce it to 10,000 km. During scheduled maintenance, the oil filter and engine oil are changed.

Compositions for filling into the K7M engine are ELF Evolution SXR 5W40 or ELF Evolution SXR 5W30 lubricating fluid. It is recommended to install the original oil filter, it has a catalog number - 7700274177. The sellers may have the following designation: 7700274177FCR210134. Another oil filter with part number 8200768913 is also suitable.

Along with the oil change, a whole range of diagnostic work is carried out:

• Checking the fuel system, which includes diagnostics of pressure and injectors.
• The condition of the spark plugs.
• Checking high voltage wires.
• Air filter replacement.

The process of changing the oil and oil filter is as follows:

1. We dismantle the lower metal protection of the motor.
2. We unscrew the drain plug with a key to "19".
3. After substituting the container, we wait until the oil drains.
4. We twist the drain plug, changing the seal. It is recommended to install a copper sealing ring.
5. Using a special puller, unscrew the oil filter. We install a new filter element by changing the sealing ring.
6. Pour new engine oil through the oil filler neck.
7. We warm up the engine. If necessary, add the liquid level so that the mark on the dipstick is between the MIN-MAX indicators.

Faults and repairs

Like all Renault engines, the K7M has problems and typical malfunctions:

1. Failure of sensors: IAC, DKPV, DMRV. You can fix the problem by replacing the elements.
2. Vibration caused by wear on the right pad.
3. Overheat. Usually it's the thermostat or water pump.
4. Troit engine K7M. In this case, the malfunction should be sought in the elements of the air-fuel mixture formation process.
5. Knock. A loud metallic noise in the engine compartment means it's time to adjust the valves.

tuning

Motor tuning is divided into two parts: chip tuning and compressor installation. In order to increase the power characteristics, it is necessary to flash the electronic control unit (ECU) with sports firmware. But before doing this, you will have to redo the exhaust system and remove the catalyst.

The second option for increasing power is to install a compressor. Factory compressors are not produced for Logan, but you can purchase a universal kit that is suitable for the K7M motor. The most suitable option from the St. Petersburg company "Auto Turbo". The kit was developed on the basis of PK-23-1 with a working pressure of 0.5 bar. You will also need to install nozzles from the Volga manufactured by Bosch 107. But do not forget that installing a compressor reduces the life of the motor by 20-25%.

Today it determines not only the total price of a budget car, but also fuel consumption, the dynamics of a budget sedan. Now we will talk in detail about the Logan engines of the first and second generation of the car. We will pay special attention to engines for the Russian market, and also talk a little about the versions of power units that are offered in other markets.

So, first generation Renault Logan appeared in our country in 2005 with two gasoline engines with an 8-valve gas distribution mechanism and a timing belt. These are 1.4 MPi and 1.6 MPi engines. The engines themselves were the closest relatives, since they were structurally similar, the difference was only in the working volume. The increase in engine size 1.6 was achieved through a new crankshaft and a higher cylinder block. That is, in fact, only the piston stroke increased from 70 to 80.5 mm. Both units are gasoline, four-stroke, four-cylinder, in-line, eight-valve, with an overhead camshaft.

The power system is distributed fuel injection (Euro-2 toxicity standards). The power of the 1.4-liter engine was 75 hp, the 1.6 engine with Euro-2 produced up to 87 hp. However, with an increase in the environmental standard to Euro-4, the power decreased to 82-83 horsepower. The 1.4 MPi engine had a factory index K7J, a more powerful 1.6 liter Logan engine model received the K7M index.

Structurally, both engines had a cast-iron block, an aluminum cylinder head, one camshaft, a timing belt. As for the valve mechanism, there were no hydraulic compensators for automatic adjustment of the thermal gap, that is, the valve gap had to be adjusted periodically manually. Another important point, in the event of a timing belt break on these motors, the valves very often bend. Further, more detailed characteristics of the engines of the first Renault Logan -

Engine Renault Logan 1.4 MPi 75 hp (model K7J) characteristics, fuel consumption, dynamics

• Working volume - 1390 cm3
• Number of cylinders - 4
• Number of valves - 8
• Cylinder diameter - 79.5 mm
• Piston stroke - 70 mm
• Power hp / kW - 75/56 at 5500 rpm
• Torque - 112 Nm at 3000 rpm
• Maximum speed - 162 kilometers per hour
• Acceleration to the first hundred - 13 seconds
• Fuel consumption in the city - 9.2 liters
• Combined fuel consumption - 6.8 liters
• Fuel consumption on the highway - 5.5 liters

Engine Renault Logan 1.6 MPi 87 hp (model K7M) characteristics, fuel consumption, dynamics

• Working volume - 1598 cm3
• Number of cylinders - 4
• Number of valves - 8
• Cylinder diameter - 79.5 mm
• Piston stroke - 80.5 mm
• Power hp / kW - 87/64 at 5500 rpm
• Torque - 128 Nm at 3000 rpm
• Maximum speed - 175 kilometers per hour
• Acceleration to the first hundred - 11.5 seconds
• Fuel consumption in the city - 10 liters
• Combined fuel consumption - 7.2 liters
• Fuel consumption on the highway - 5.7 liters

Later, Renault Logan received a more powerful 1.6-liter gasoline engine with 16 valves. Essentially the same 1.6 K7M engine, but with a different cylinder head. Now two camshafts have appeared in the timing drive, and power has increased to 102 hp. The new Renault Logan engine received the K4M index. The new DOHC cylinder head received hydraulic lifters, now there is no need to manually adjust the valves. If the timing belt breaks on the 1.6 16V engine, the valve bends, keep this in mind if you do not want to get into a cylinder head overhaul. Further, more detailed characteristics of this Logan engine -

Renault Logan 1.6 16V 102 hp engine (K4M model) characteristics, fuel consumption, dynamics

• Working volume - 1598 cm3
• Number of cylinders - 4
• Number of valves - 16
• Cylinder diameter - 79.5 mm
• Piston stroke - 80.5 mm
• Power hp / kW - 102/75 at 5700 rpm
• Torque - 145 Nm at 3750 rpm
• Maximum speed - 180 kilometers per hour
• Acceleration to the first hundred - 10.5 seconds
• Fuel consumption in the city - 9.4 liters
• Combined fuel consumption - 7.1 liters
• Fuel consumption on the highway - 5.8 liters

Second generation Renault Logan in addition to 8 and 16-valve engines with a volume of 1.6 liters, it received a completely new 16-valve engine with a working volume of only 1.2 liters (engine model D4F). In particular, it is already being installed on Sandero. Actually, the engine itself “grew” from an ancient 8-valve (engine model D7F) of the same volume, which produced a ridiculous 59 hp. The appearance of a new cylinder head with 16 valves increased power to 75 hp. In fact, this is a replacement for the retired 8-valve 1.4-liter engine, which was installed on the first Logan. The design of the 16-valve mechanism is interesting. A feature of which is only one camshaft, which, with the help of rocker arms, is controlled with all 16 valves. In the timing drive, again, the belt. Characteristics of the new motor for Logan / Sandero further -

Engine Renault Logan/Sandero 1.2 16V 75 hp (model D4F) specifications, fuel consumption, dynamics

• Working volume - 1149 cm3
• Number of cylinders - 4
• Number of valves - 16
• Cylinder diameter - 69.0 mm
• Stroke - 76.8 mm
• Power hp / kW - 75/55 at 5500 rpm
• Torque - 107 Nm at 4250 rpm
• Maximum speed - 156 kilometers per hour
• Acceleration to the first hundred - 14.5 seconds
• Fuel consumption in the city - 7.7 liters
• Fuel consumption in the combined cycle - 6 liters
• Fuel consumption on the highway - 5.1 liters

It is worth noting a number of motors that are put on Logan for foreign markets. For example, in Brazil there is a 16-valve engine with only 1 liter capacity of 76 hp. This aspirated can consume not only gasoline, but also ethyl alcohol, on which some of the transport of this Latin American country moves. It just so happened that distilling ethyl alcohol from cane sugar is much cheaper there than distilling oil into gasoline.

In Europe, a new turbocharged 3-cylinder engine with a volume of only 0.9 liters is gaining popularity. At the same time, the power unit produces 90 hp. and good torque. Other markets offer several 1.5 dCi diesel options ranging from 75 to 85 hp. These engines are very popular in India, although Logan is called Mahindra Verito there, by the way, in Mexico it was called Nissan Aprio. In general, the world model with a large selection of power units for every taste.

Over the years of Renault's existence, the concern's products have been equipped with different engines. Since 1999, the K4M engine has been installed on the popular models of Logan, Sandero, etc., and some samples of the domestic model Lada Largus are also equipped with it.

Overview and Specifications

The next important point is the air filter, its condition directly affects the operation of the engine: the worse the air passes through the filter, the more the engine “suffocates”, loses power, and starts to work with failures. According to the regulations, the air filter should be changed every two years, or after about 30 thousand runs.

Air filter:

If the car is operated in a high dust content of the air, it needs to be changed more often.

The engine is quite sensitive to fuel and does not tolerate 92 grades well, although the manufacturer does not give a direct ban on 92 gasoline. It is advisable to pour high-quality fuel with an octane rating of 95 into the tank.

Candles are subject to regular replacement: according to the manufacturer's regulations, this is done every 30 thousand runs. The catalog number of the "factory" candles is 7700500155, but compatible ones are also allowed - EYQUEM EQ-RFC58LZ2E, etc., which can be found in the catalogs.

Tuning K4M

Car owners have learned to extract more power from this engine than in stock. Possible options for tuning the K4M 16V engine:

• The engine lends itself well to firmware, this can improve the dynamic and power performance of the motor, especially if the exhaust is modified in parallel to a catatless one.

Installing a compressor on K4M

• The motor is suitable for the installation of pressurization, for example, a PK-23 compressor, this will allow the unit to be boosted to about 145 forces. To do this, you will also need to replace the nozzles, put in a direct-flow exhaust, new shafts under the appropriate load, and install a control unit.

• More advanced tuning option. The operation is similar to installing a compressor, but instead a turbine is placed on the engine, for example, TD-04. More than 150 forces can be squeezed out of the engine.

It is important to remember forcing the engine reduces its resource, the more power, the less the engine will last.

Common Problems

Despite all the above advantages and simplicity of the device, the K4M engine has earned a reputation for being problematic among many car owners. There is a significant reason for this.

• Pulley problems. In 2010, a batch of K4M engines with a defective damper pulley was discovered on the Russian market. “Unlucky” for the owners of Sandero and Logan: cars equipped with these engines at one moment found a shaft of black smoke from under the hood.

The cause of the malfunction was a broken crankshaft pulley due to a collapsed damper spring. Often, along with this, the timing case melted, there was a jump / shift of the timing, bending of the valves, damage to the cylinder head, scuffing of the cylinders, damage to the engine pistons, etc. Moreover, this could happen on new cars, literally just from the salon. The problem was aggravated by the fact that if the breakdown occurred on the go, at speed, the driver lost the hydraulic booster, and the car turned into a poorly controlled projectile.

In total, the defect in 2010 was found on about 100 cars. The overhaul period was, on average, about a month. The engine manufacturer refused to recognize the trend towards marriage. And to this day, sometimes there are reports of a car breakdown on K4M with similar symptoms, although failure cases cannot be considered massive.

Common faults

• Motor troit.

Probably the ignition coils or spark plugs are out of order. They should be checked and replaced if necessary.

• "Float"

The cause may be a junky idle speed controller, a leaky air intake system (“leakage”), throttle contamination.

• Faulty phase regulator.

The resource of this block is about 100 thousand km, but replacement may be required earlier.

• Leaks of antifreeze and oil.

The most problematic places are the engine crankshaft oil seal and pump. It happens that the valve cover begins to “sweat” and even clearly leak.

• Icing of the motor with subsequent breakdown.

This problem affects some cars with a lack of design, and only in cold weather. Snow can fall under the engine hood, it sits on the casing of the gas distribution mechanism and melts, the resulting water flows down to the bottom of the belt and freezes in a kind of growth. When the car is started, this "ice" gets under the gear, the timing jumps, and the valves hit the pistons.