Eight-cylinder gasoline engines ZMZ 53 (often called GAZ 53, although this is wrong) were used on a huge number of different equipment: GAZ trucks , PAZ and KAVZ buses . Several engine versions continue to be produced today.
Supply system
All ZMZ 53 engines were equipped with a carburetor power system. In addition to this device, the system included a fuel pump, a tank or tank system for storing fuel stock, filters and pipelines for communication of the system nodes. Below we will consider the general structure of the main unit of the power system - the vertical carburetor K 135.
general description
This model came in 1985 to replace the K 126. The appearance of the new device was associated with the modernization of the ZMZ engine family. The body of the new carburetor has not changed, in fact, only the passage sections of the nozzles have changed.
A valve fitting for the exhaust gas recirculation system was added to the housing .
Features of the upgraded engine
The K 135 carburetor (like K 126) has two chambers, each of which provides a working cylinder of 4 cylinders. On older versions of the engines, there was an intake manifold with crossing channels at different levels. The first chamber fed the cylinders 1, 4, 6 and 7, the second - 5, 2, 3 and 8. The carburetor compartments worked in accordance with the order of the flashes in the engine parts. The old type collector in the photo below.
On the modernized engine, the collector was simplified, and each camera became responsible for the cylinders of its block. This decision made the collector cheaper. But there were uneven pressure pulsations in the chambers of the K 135 carburetor. Because of such pulsations, there is a spread in the characteristics of the mixture in different cylinders and at different times of engine operation. The new collector can be seen in the photo.
But thanks to the new nozzles, it was still possible to improve the toxicity standards of GAZ 53 engines. The K 135 carburetor provided the preparation of more lean working mixtures, which slightly smoothed out the heterogeneity of the mixture. A new manifold and a carburetor, together with new cylinder heads with an increased compression ratio and screw walls of the inlet channels, made it possible to improve the fuel economy of engines by 6-7%. At the same time, the requirements for the octane number of gasoline did not change.
General device
The carburetor circuit K 135 is quite simple. In fact, it represents two independent nodes assembled in one housing and united by a common float chamber. Accordingly, there are two metering systems. They include the main diffuser, in the constriction of which there is a fuel atomizer. Below is a mixing chamber, the output of the mixture from which is regulated by a gas damper.
The dampers have a common axis, which ensures almost the same amount of air passing through the carburetor chambers. The axis of the dampers is connected by rods to the accelerator pedal of the car.
The metering system provides fuel in proportion to the supply air. A key element of the system is a narrow channel diffuser. When air passes through it, a reduced pressure is created, depending on the speed of the passing stream. Due to this phenomenon, fuel is taken through the main fuel jet from the float chamber. Access to these nozzles is possible without disassembling the carburetor and is carried out through screw plugs in the body of the float chamber.
The fuel level is automatically adjusted by a needle valve and its associated float. On older models of carburetors, there was a control window in the chamber wall. To maintain the composition of the mixture, the K 135 carburetor is equipped with a compensation system with air braking of the fuel.
At low speeds, the air flow is small and there is a lack of vacuum in the dosing unit. To ensure engine operation in this mode, an idle system is used.
For the most complete realization of engine power and dynamic acceleration, the K 135 carburetor is equipped with an economizer and an accelerator pump. Of the additional systems, it is worth noting the starting device and the engine speed limiter.
Customization
This element of the car is quite simple in design and does not require much attention with proper operation. Adjustment of the carburetor K 135 includes tuning the starting device, monitoring the fuel level in the chamber and tuning the idle system.
When adjusting the starting device, it is necessary to close the air damper, which will move the gas damper to the start position through the draft. The clearance between the gas damper and the chamber wall must be within 1.2 mm. The adjustment of the device consists in setting this parameter and is performed using the adjustment bar in the damper actuator. Easy starting of a cold engine is only possible with the specified clearance.
Another important step in adjusting the K 135 carburetor is to set the fuel level in the float chamber. To do this, measure the distance between the float and the plane of the cover. It should be 40 mm. Measurement is carried out on the removed cover in an inverted state. The distance is adjusted by bending the tab of the valve needle drive. At the same time, it should not have any damage or dents. The final control of the fuel level is made on the installed carburetor.
Repairs
Dismantling and repair of the K 135 carburetor is carried out in case of damage to parts or severe contamination of the device. However, washing and cleaning should not be abused. After all, there is a risk of clogging the channels inside the carburetor with dirt and disrupt the run-in connections.
One of the most common operations is flushing the float chamber. In this case, only easily removed deposits are removed. Mud tightly attached to the walls should not be cleaned. Deposits in the chamber are a consequence of the poor condition of the fuel filtration system. Therefore, cleaning should be combined with replacing and cleaning the filters.
When disassembling the carburetor, attention should be paid to the condition of the nozzles; if necessary, they should be washed. The condition of the floats (they are of two types - brass and plastic), the axes of the dampers, the accelerator pump is checked. All damaged parts should be replaced with new ones.
Separately monitor the condition of the surfaces of the mating parts of the housing. If necessary, they are ground on a calibration plate.
Upon completion of the work, reassemble, tune and install the carburetor on the engine.