Opel Z12XEP engine - AvtoTachki

Content

The history of the appearance of the engine
The emergence of Z12XEP and compliance with new environmental standards
Technical specifications
Reliability, weaknesses, maintainability
Engine tuning
List of cars on which this engine was installed

Z12XEP - gasoline engine, gas equipment can be installed. The maximum engine power reached 80 hp, the volume was 1.2 liters. Mounted on Opel Corsa C/D and Agila cars. Manufactured by Aspern Engine Plant, produced from 2004 to 2009, after which it was replaced by the A12XER model. ICE developed based on Z14XEP.

In the new model, the pistons, connecting rods and crankshaft were slightly changed. The valves do not require adjustment, hydraulic compensators are installed. Maintenance of the engine according to the regulations was to be carried out every 10 thousand km. mileage recommended by the manufacturer after 8 thousand km. All requirements in this matter are similar to the Z10XEP engine model.

Z12XEP

The history of the appearance of the engine

12NC - this marking had an engine that ran on gasoline and had a volume of 1.2 liters. These motors were installed on the first generation of Corsa, but the outdated design did not meet the new demands of the automotive market. The next modification of the C12NZ appeared in 1989, when a number of engines were developed that had a similar design. The differences were in power, cylinders and volume.

The C12NZ unit had a cast iron and high strength cylinder block. The cylinder head had two valves per cylinder, a shaft on top, a hydraulic compensator. The cooling pump and camshaft were driven by a toothed belt. A camshaft was installed on the block in an aluminum mold. It was easy to replace, the only drawback was the valve cover - the gasket lost its elasticity and, as a result, oil leaked.

Timing chain for Opel Corsa D with Z12XEP engine

Starting in 1989, the C121NZ ICE was produced with a displacement of 1196 cubic meters. see, liquid cooling system, four in-line cylinders, separate manifolds. The X12SZ had similar characteristics. With virtually no modifications, the engine was installed until the introduction of the Corsa B in 1993.

Then minor adjustments were made, and an improved 12NZ model appeared. Power remained the same, the main difference was in the control electronics. The timing drive with a power reserve of at least 60 thousand km was characterized by good reliability.

The advantage of the motor was inexpensive spare parts and a simple design.

The next modification X12XE appeared as a result of new market demands. A number of significant changes were made to the design of the unit:

the toothed belt was replaced with a roller chain, this did not affect the replacement schedule every 100 thousand km. mileage, but the maintenance and price of the parts of the installed chain drive turned out to be higher;
block head with 16 valves, improved filling of cylinders with a combustible mixture, increased power to 65 hp. with., traction and dynamic characteristics;
the beds of the main liners are made as a single part, the rigidity of the structure of the entire unit is increased.

Changes to the cylinder head led to the development of a different injection system, which increased power and fuel consumption. This ICE model was installed on the Corsa and with the advent of the Astra G in 1998. The engine had a good resource, was easy to maintain, its mileage could be more than 300 thousand km. when used correctly. It is possible to grind the crankshaft and bore the block under three repair sizes during the overhaul.

Opel Astra G

In 2000, another modification was carried out, the power unit was named Z12XE. In this model, the camshaft / crankshaft and fuel injection system have been worked out, and the power of the unit has been increased to 75 hp. With. But the increased loads forced the use of better, and therefore expensive motor oil. The requirements for lubricant standards have also increased. But compliance with the requirements of operation and maintenance guarantees a good motor resource.

The emergence of Z12XEP and compliance with new environmental standards

Since 2004, production of the Z12XEP began, in which the main difference is the Twinport intake manifold. At low speeds, the combustible mixture in it is supplied only through 4 intake valves, and not 8. This increased traction and power up to 80 hp. with., decreased fuel consumption and emissions of harmful substances.

In 2006, they released a new Corsa D on which the Z12XEP engine was mounted, but over time it ceased to meet the stringent environmental safety standards introduced in Europe.

Because of this, a modification of the A12XER (85 hp) and A12XEL (69 hp) was released into production. The latest modification had more narrow emission characteristics. The power reduction occurred as a result of working out the software and electronics settings, the Twinport system was not installed. Instead, an intake manifold was used, which could change the flow area. Over time, the weight and dimensions of the new Astra increased, so the 1.2-liter engine. simply ceased to be relevant and was no longer installed on this model.

Technical specifications

Food	Injector
Number of cylinders / valves per cylinder	04.04.2019
Engine displacement, cc	1229
Fuel/environmental standards	Petrol 95, gas/Euro 4
Fuel consumption for Corsa C highway/city/combined	4.9/7.9/6.0
Oil consumption gr / 1 thousand km.	Until 600
Engine oil/l/change every	Excl. 5W-30, 5W-40/3.5/15. km.
Torque, Nm/rev. min.	110/4000
Engine power, hp / rev. min	80/5600

High-quality and durable cast iron is used for the cylinder block. The unit is in-line, piston stroke 72,6 mm, cylinder diameter 73,4 mm. An engine oil change should be carried out after 15 thousand km. mileage, however, experts recommend doing every 7,5 thousand km. The operating temperature in the engine reaches 95 degrees, the compression ratio is 10,5. With careful attention to the device and proper care in practice, the resource of the unit is more than 250 thousand km. without the slightest problem. The engine number is located below the oil filter. During operation, it is often covered with dirt, so you will have to wipe part of the body with a rag to find it.

Reliability, weaknesses, maintainability

For the first time, the Z12XEP engine was installed on the Opel Agila, it replaced the Z12XE modification. This modification uses developments from the Z10XEP.

Opel Agila with Z12XE engine

However, it is mainly based on the Z14XEP model with some changes:

in the cylinder block, a crankshaft with a piston stroke of 72.6 mm .;
the height of the new pistons is 1 mm higher. from the previous modification and is 24 mm .;
long connecting rods are installed;
the diameter of the exhaust / intake valves was 28/25 mm. respectively;
valve stem diameter is only 5 mm.

At the same time, valve adjustment was not required, since a hydraulic compensator system was used.

The intake / exhaust systems, the control unit, the electronic gas pedal and the camshafts, which are activated by a single-row timing chain, the resource of which could reach more than 14 thousand km, remained similar to the Z150XEP.

Since October 2009, the production of this motor has been discontinued, as it has become irrelevant. Eat was replaced by the A12XER modification.

This engine model is an almost complete copy of the Z14XEP. Accordingly, all the most common problems are similar to this motor:

The appearance of a knock, a sound reminiscent of the operation of a diesel engine. Basically the problem is with the Twinport or a stretched timing chain. The chain was easily changed to a new one, and in the issue with Twinport, it is necessary to look for the very reason, repair it or completely replace it, fix the dampers open and turn off the system. However, for the operation of the engine without Twinport, it was necessary to reconfigure the ECU.
The speed drops, the car stalls, does not go. Almost always the problem was a very dirty EGR valve. It had to be well cleaned or jammed. When the EGR failed, unstable revolutions appeared.
Sometimes the engine overheated due to a breakdown of the thermostat, fan sensor, cooling system pump or expansion tank plug. With an increase in operating temperature beyond the permissible limits, cracks could appear in the cylinder block, and the block head was deformed. It is urgent to carry out diagnostics, identify the problem, change parts.

Another fairly common problem was less commonly noted - lubricating fluid was leaking through the oil pressure sensor. In this case, there was only one solution - replacing the sensor, and it is best to use only the original one. In all other respects, the engine is quite good, and with proper care, operation and maintenance, the use of high-quality fuel and lubricants, and maintaining the correct oil level, its life could reach 300 thousand km.

Engine tuning

Specialists could increase the power of this motor in the same way as the Z14XEP model. To do this, it was necessary to muffle the EGR by first putting a cold inlet. Then the collector changes to 4-1, after which the control unit is configured differently. This modification will add an internal combustion engine up to 10 liters. with., and also increase the dynamics. Any other tuning did not give the desired result, so it was completely useless.