402 engine, "Gazelle": cooling system, scheme

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

"Gazelle" - perhaps the most popular small truck in Russia. These cars are found on the streets every day. Few people remember, but the first Gazelles came with engines and gearboxes from the usual Volga. In this form, the Gazelle was produced from 1995 to 2002. inclusive. It was the engine of the Zavolzhsky Motor Plant, which received the ZMZ-402 marking. What characteristics and features does it have? Find out in our article today.

Description

The ZMZ-402 engine is one of the most massive ever produced in the Volga region. This motor has an aluminum block with "wet" cast iron sleeves. The camshaft is at the bottom. This unit was mass-produced from 1981 to 2006. Initially, the 402 engine for the Gazelle was not provided. It was a modernized 24D engine, which is installed on the Soviet Volga. Among the significant differences between the 402nd motor, it is worth noting the modified exhaust manifold,a different camshaft lift (it has become 0.5 mm higher) and an oil pump. Otherwise, the ZMZ-402 was a copy of the 24D engine - an engine from the 50s. We will talk about the problems of the internal combustion engine later. By the way, the diagram of the Gazelle engine (402 ZMZ) is in the photo in our article.

Specifications

So, ZMZ-402 is a gasoline in-line four-cylinder engine with a displacement of 2440 cubic centimeters. The unit has the simplest carburetor power system with a mechanical fuel pump.

The timing system is eight-valve, chain-driven from the crankshaft. 402 Gazelle engine has a 92 mm piston stroke. The cylinder diameter is also 92 millimeters, which is why the engine had a low compression ratio and compression. Normally, this parameter was 8.2 kilograms per cubic centimeter. An indicator of 6.7 kilograms was considered critical. Along with a low compression ratio, the 402 Gazelle engine was notable for its low power. The maximum power, which was achieved at 4.5 thousand revolutions, was 100 horsepower. Torque - 182 Nm at 2.5 thousand revolutions. And if for the Volga this parameter was still enough, then for the Gazelle it is no longer there. The car was sensitive to the slightest overload. Eight-degree climbs seemed like a real test for her. The oil recommended by the manufacturer is 5w30-15w40. When replacing, it is necessary to pour up to six liters. The oil change schedule is ten thousand kilometers. But motorists recommend doing it earlier, at eight thousand.

Carburetor on Gazelle with 402 engine

As for the power system, the domestic carburetor "Pekar" model K151 was used here. This is a standard element with which all 402 engines were equipped. Gazelle was no exception.

How does K151 perform in action? According to the reviews of the owners, "Pekar" is not the best carburetor. On the Gazelle with a 402 engine, the Solex behaves well. It does not have such disadvantages as "Pekar":

• Fuel consumption. With the K151 carburetor, the Gazelle spent about 25 liters of gasoline, and the 92nd. Installing "Solex" allows you to reduce this parameter by about a quarter.
• Engine running. No matter how motorists tried to tune the Pekar, the engine still worked unsteadily. RPMs fluctuated at idle, and there were dips during acceleration. Solex has no such problems.
• Resource. K151 has a small resource. After 50 thousand kilometers, he fell into disrepair. Moreover, K151 was beyond repair - attempts to install a repair kit were in vain. The motor ran even worse. By the way, K151 could fail earlier. A known disease is the jamming of the secondary chamber damper. "Solex" has twice the resource and is easily repairable.

Valves

As we noted earlier, the ZMZ-402 is an eight-valve engine, so there is only one camshaft in the timing system. Among the frequent problems is the need to adjust the valves. On a Gazelle with a 402 engine, it should be done every 30thousand kilometers. Moreover, the gaps are adjusted strictly for each type of fuel. The manufacturer states that the clearance on both valves (intake and exhaust) should be 0.4 millimeters.

But as practice shows, other settings are needed for the normal operation of the motor. Valve adjustment on a Gazelle with a 402 engine for 92nd gasoline should be done as follows. For intake valves, the clearance is 0.30 mm, for exhaust valves - 0.25. But to drive on 76th gasoline, you need to increase this parameter to 0.44 mm. As for most of the Gazelles from the 90s that are operated today, they run on propane-butane. Under this fuel, its own thermal gap is 0.35 mm. It is with these characteristics that the car will be torquey and torquey.

Cooling system

Any internal combustion engine needs to be cooled. The 402 Gazelle engine was no exception. The engine cooling system of this model is liquid type, with forced circulation from the pump. The SOD scheme is presented in our article.

The device of this system is the same on all Gazelles. The only thing is that two heaters and an additional electric pump are installed on the minibus modifications. The SOD design includes:

• Thermostat.
• Expansion tank.
• Radiator.
• A fan driven by the crankshaft.
• Coolant temperature sensor.
• Belt (forfan drive).
• Cabin radiator.
• Water pump.
• Bypass valve.
• Heating system electric pump.

The manufacturer recommends using Antifreeze A-40 as a coolant. The motor also runs on pure distilled water. However, it cannot be used in winter.

Below we will consider the most important elements of the cooling system 402 of the Gazelle engine.

Thermostat

SOD consists of two circles - small and large. According to the first, the liquid circulates until the engine warms up. As soon as the temperature reaches a predetermined mark (usually 70-80 degrees), the antifreeze moves in a large circle. What is a thermostat for? It is he who controls the adjustment and supplies the liquid along a certain circuit, depending on its temperature. As for the malfunctions of the thermostat on the 402nd motor, the wedge of the element often occurs in a closed form. In view of this, the motor begins to overheat, since the liquid circulates only in a small circle, bypassing the main radiator.

Pump

Its other name is a water pump. This mechanism ensures the circulation of antifreeze in the cooling system. Works part from the crankshaft. The higher its speed, the more the pump impeller spins.

Among the malfunctions of the pump on the 402nd motor, it is worth noting the howl of the bearing. In this case, the pump is disassembled and the shaft assembly with the bearing is changed. Also, the stuffing box, pulley and impeller become unusable.

Fan and radiator

From the factory, a three-row copper radiator is installed on the Gazelle with the 402nd engine. It is quite durable and lasts a very long time. But over time (especially when using low-quality coolant), internal corrosion of the metal begins. Because of this, heat dissipation deteriorates and the engine is very hot. Corrosion also leads to antifreeze leaks. As for the fan, it has six blades and is mounted on the crankshaft pulley. The element rotates with the same frequency as the shaft itself. The fan runs constantly, which is why the 402nd motor cannot heat up normally in winter.

Heating elements

This includes:

• Cabin radiator.
• Heater fan with electric motor.
• Connecting pipes.
• Controls for cable operated stove.

The cable often breaks, which closes the valve on the stove. Because of this, it warms both in summer and in winter. The heatsink and fan itself last relatively long.

Water jacket and fittings

The first is in the cylinder block itself, as well as in the cylinder head. The principle of operation of the water jacket is simple. Cold antifreeze that comes from the radiator enters the channels of the block and takes away part of the heat. Then the liquid again enters the radiator and cools. Among the malfunctions of the shirt, it is worth noting clogging of the channels and internal corrosion. Again, the culprit for this problem is low-quality coolant.

Gazelle generator (402 engine)

Let's talk a little about attachments. The ZMZ-402 engine is completed65 amp alternator model 1631.3701. This is a three-phase synchronous generator with a built-in silicon diode rectifier. It is driven by a belt from the crankshaft pulley. The rotor rotates on ball bearings that are in the covers. It should be noted that the lubrication of the rotor shaft is laid for its entire service life. Inside the back cover there is a rectifier block that regulates the voltage. The rectifier consists of six diodes that are installed in horseshoe-shaped plates. This generator can produce current from 12 to 14 volts. The stator has two three-phase windings connected to each other in parallel. Cooling - air type, through windows in the lid.

For excitation, there is a winding on the generator rotor. Its conclusions go to two copper contacts that are connected to the rings of the rotor shaft. Power is supplied through carbon brushes. Among the problems of this generator, the owners distinguish low power. For full operation, a minimum of 80 Ah is required. Also, the generator brushes and the “chocolate” (voltage regulator) often fail.

Resource

Repair of the 402 Gazelle engine will be needed no earlier than after 200 thousand kilometers. For a commercial vehicle, this is not a long time. The motor can "capitalize" up to four times. And so that the repair of the Gazelle engine does not take a long time, you need to change the oil in it in time and not overheat the engine.

You should also set the correct ignition. On a Gazelle with a 402 engine, it is exhibitedon the distributor. Adjusting the ignition timing will keep the valves from burnout and increase the throttle response of the engine.

In conclusion

So, we found out what the ZMZ-402 engine is. The design of this motor is very outdated, as a result of which frequent breakdowns occur with it. Therefore, the owners of old Gazelles install more modern 405 and 406 engines instead. At the same consumption, they produce much more power and torque. And breakdowns with them happen much less often.