In the article, we will consider the exhaust gas recirculation system, the exhaust gas exhaust system and the engine mount

The rest of the ZMZ-402 engine systems are discussed in the following articles:

  • - Engine cooling system - Engine cooling ZMZ-402 GAZ-2705
  • - engine lubrication system - Oil system ZMZ-402 GAZ-2705
  • - ignition system - Ignition system engine 402 GAZ-2705
  • - gas distribution mechanism - Gas distribution mechanism ZMZ-402 GAZ-2705
  • - engine power system - ZMZ-402 power system features

Crankcase ventilation system - closed forced acting due to vacuum in the intake pipe and air filter

When the engine is running, gases are sucked out of the crankcase: at idle and low loads - through a calibrated carburetor hole into the intake pipe at full load - through an air filter, in other modes - through an air filter and a calibrated carburetor hole

On a running engine with a good ventilation system, there should be a vacuum in its crankcase, which can be determined using a water piezometer connected to the oil level indicator pipe.

If the system is not working properly, there will be excess pressure in the crankcase. This is possible in case of coking of ventilation channels or excessive breakthrough of gases into the engine crankcase.

When operating the car, do not break the tightness of the engine crankcase ventilation system and do not allow it to operate with an open oil filler neck: this causes increased engine wear.

Engine recirculation system

 EGR Scheme

Some cars are equipped with an exhaust gas recirculation system, which consists of a recirculation valve 8 installed on the gas pipeline, a thermal vacuum switch 4 screwed into the water jacket of the cylinder head, and two connecting hoses.

Exhaust gas recirculation into the intake tract is carried out on the engine warmed up to a coolant temperature of at least 35-40 ° C, at partial loads.

The exhaust gas recirculation system does not work at idle and at full throttle.

To check the performance of the exhaust gas recirculation system, on a warm engine, increase the idle speed of the crankshaft from a low speed to 3000 minˉ¹ no more, and visually observe the movement of the valve stem 8.

If the stem does not move, check for control vacuum on the diaphragm mechanism of the recirculation valve.

If there is a vacuum, then the valve is faulty and needs to be replaced.

If there is no control vacuum, the thermal vacuum switch must be replaced.

Exhaust system

The exhaust system consists of an engine exhaust manifold, exhaust pipes connected by a gas inlet, a resonator, a silencer and an exhaust pipe.

The muffler and resonator of a non-separable design are attached to the frame using brackets and rubber shock absorbers.

 ZMZ-402 engine mount

Engine mount consists of two engine brackets, two rubber mounts located on either side at the front of the engine, and a rear rubber mount under the transmission extension.

Rubber pads are mounted on the crossbars of the frame.