Engine UMP 421: description, characteristics, features and reviews

The engine with the UMP 421 index is produced at the production facilities of the Ulyanovsk Motor Plant (UMP). This company since 1970 has been producing automobile engines.

Prerequisites of creation

The first products of the plant were four-cylinder carburetor engines GAZ 21 and ZMZ 451 (both with the same cylinder capacity of 2445 cc). Production of these engines was transferred to Ulyanovsk from Zavolzhsky Engine Plant. During production, the engines underwent several upgrades, but by 1990-91 almost had no further prospects for improving the design, increasing the power characteristics and simultaneously reducing fuel consumption. By this time, the need to improve the competitiveness of UAZ production cars in a market economy led to the need to create engines with high torque and maximum power.

UMP 421


By 1996, the engine of a new model with a cylinder capacity of 2890 cc, which met the new requirements, was developed and introduced into mass production. The project was named UMP 421. In fact, the UMP 421 was the latest version of the GAZ 21 engine, which went into production in 1957. Thanks to the increased working volume, increased exhaust valves (diameter increased by 3 mm - up to 39 mm) and a number of other improvements, it was possible to increase the torque to 22.6 kgf / m and power up to 125 hp. (previous models had a moment of no more than 17 kgf / m and power not higher than 80-90 hp).

Engine UMP 421

Within the framework of the UMP 421 project, there were several dozens of engines, differing from each other by compression ratio, power supply system, mounted units, type of drive of mounted units and other nodes. The lubrication system of all motors is combined, from a gear pump. About 6 liters of oil is required for replacement, semi-synthetic oil is recommended with tolerances of 5W-30, 10W-40, 5W-40 or 20W-40. The cooling system of the motor liquid, with the forced circulation of fluid from the pump.

New cylinder block

A noticeable difference in the new engine was the aluminum cylinder block of the new design.UMP 421 received dry thin-walled cast iron sleeves poured into the body of the unit (all the predecessors were wet). Thanks to this solution, the designers managed to obtain increased rigidity and strength of the block, as well as to increase the diameter of the cylinders by 8 mm (from 92 mm on the old block to 100 mm on the new one). Inter-cylinder distance has not changed and is 116 mm.

UMP 421 price

This solution allowed not only to preserve the interchangeability of engine parts of different generations, but also significantly reduce the cost of new equipment for processing units. In addition, the overall and landing dimensions of the engine remained unchanged, which allows the UMP 421 to be used on machines of previous years of release.

Piston group and crankshaft

Due to the increased rigidity of the unit, it was possible to somewhat reduce the non-uniformity of wear of the cylinder mirrors, which increased the service life of the cylinder-piston group. The piston mass has been reduced to reduce the forces on the side of the piston. This was achieved by reducing by 7.5 mm the distance from the axis of the piston pin to the bottom of the piston. To compensate for this distance, the rod length is increased by 7 mm. Pistons cast aluminum with high silicon content.Part of the combustion chamber is located in the bottom of the piston (notch in the shape of a truncated cone).

Cylinder head UMP 421

Crankshaft cast iron. Radical necks have a diameter of 64 mm, connecting rod - 58 mm. A flywheel is fixed on the rear of the shaft, and a cast-iron camshaft drive gear and a pulley hub are fixed on the front. In order to prevent axial play of the shaft, two washers are installed on the front main bearing. Instead of outdated packing, the rear part of the crankshaft of the UMP 421 is sealed with a self-pressing rubber gland. This solution allowed to get rid of the long-term problem hereditary from ZMZ - the leakage of oil through the gasket.

Cylinder head

Due to the preservation of the inter-cylinder distance, it was possible to unify the cylinder head on 2445 cc engines. cm and 2890 cc The cylinder head of the UMP 421 is made of aluminum alloy and is fitted with plug-in valve seats made of heat-resistant cast iron. The unification of the cylinder head has led to the preservation of the old scheme of the timing mechanism - the camshaft in the cylinder block (at the bottom) and the valve drive with rods, tappets and rocker arms.

Valves UMP 421 do not have a hydraulic gap gap (with the exception of some modifications of the engine of release after 2010) and require adjustment after 10-15thousand km In 2010, the engine camshaft changed, the profile of which increased in height. This event allowed to improve the idle mode and achieve Euro-3 emission standards.

Major versions

The basic carburetor model of the UMP 421 had a tuned exhaust system. The system included the exhaust manifold, muffler, exhaust pipe muffler and resonator. However, such a gas exhaust system caused difficulties with the installation of such engines on some production UAZ cars, especially with a car body type ("loaf"). These difficulties led to the appearance of modifications with an unconfigured release system.

Valves UMP 421

In 1998, UMP launched a new market for itself - deliveries of engines for the UMP 4215 model for light-duty trucks GAZ OAO began. At the same time, increasing requirements for exhaust emissions led to the installation of UMZ engines with fuel injection systems with fuel supply control and ignition parameters using electronic control units. The first engines with such systems were shipped to customers in 1999-2000 - the motor with the UMP 4213 index was installed on the UAZ-3160 cars.

For a complete set of cars, the UAZ was supplied with 98-strong 4218.10 (with a grade of 7.0 for A80 petrol) or 103-strong for 4,218.10-10 (with a grade of 8.2 for A92 petrol). Accordingly, the motors could be with different exhaust systems. Also for the needs of the UAZ produced 117-strong 4213.10-40 with a fuel injection system. 4213.10-50, 4215.10-10, 4215.10-30 and 123-strong injection 4216.10 engines were manufactured for GAZ cars.

Basic engine data UMP 421 (basic version)
Number of cylinders 4
Working volume 2890 cu. cm
Compression ratio (A76 / A92) 7,0/8,2
Rated power 98 hp (72 kW) at 4000 rpm
Maximum moment 167 N / m in the range from 2200 to 2500 rpm
Engine weight 170 kg
Environmental class Euro 0

Pros and cons of the engine

The new block of cylinders did not always have high quality casting, which led to the ingress of oil into the cooling system. Sometimes this problem arose through the first 10 thousand kilometers. The thin-walled unit was prone to deformation when overheated, which leads to costly repairs with the replacement of the cylinder head. Low fuel efficiency carburetor versions. However, this disadvantage is partly offset by the transition to injection systems. The first years of production were the owners' complaints about the inadequate strength of the intake manifold, but this defect was eliminated.

Crankshaft UMP 421

Despite all the problems, a large unification with the engines of previous years of production has become one of the weighty advantages of the UMP 421 family. The price and prevalence of spare parts also play a significant role. The motor is quite easy to repair and maintain. With proper care, the plant promises a resource of at least 250 thousand km.

UMP 421 - more than 20 years in production

At present, the UMP continues to produce engines of the 421 family. For the GAZ products, a gas-cylinder version of the engine is being produced, which can be completed with an air conditioning compressor and hydro-compensators in the valve drive. By request, the engine is equipped with a modern drive units poly V-belt. The engines are equipped with a fuel injection system, electronic ignition and develop from 100 to 125 forces with the observance of Euro-3 or 4. In addition, the 96-strong carburetor version 4215 remained in the series. All engines are designed for A92 gasoline and higher, as the production of low-octane A80 discontinued.

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