The YaMZ-236M2 and YaMZ-238M2 engines are six- and eight-cylinder models of the family of four-stroke diesel engines of Avtodizel OJSC

The YaMZ-238AM2 engine is a modification of the YaMZ-238M2 engine, the power of which is limited to 225 hp. for the entire period of operation.

The YaMZ-238VM engine has the same rated power and maximum torque as the YaMZ-238M2 engine, it is distinguished by its completeness and a special oil pan that allows operation at increased rolls and trims.

General view of YaMZ-236M2 diesel engine

In Figure 1, a general view of a diesel engine

The YaMZ-238GM2 engine is designed for stationary or cyclically variable operation and differs from the YaMZ-238M2 engine mainly in the configuration and adjustment of the fuel equipment.

Longitudinal section of YaMZ-236M2 diesel engine

In figure 2, a longitudinal section of a diesel engine

The YaMZ-238KM2 engine is designed for installation on an underground dump truck.

Cross section of YaMZ-236M2 diesel engine

In figure 3, a cross section of a diesel engine

YaMZ-236M2, YaMZ-238M2, YaMZ-238AM2, YaMZ-238VM, YaMZ-238GM2 and YaMZ-238KM2 engines are interchangeable with YaMZ-236M, YaMZ-238M, YaMZ-238AM, YaMZ-238VM, YaMZ-238GM ​​and YaMZ-238KM, produced before 1988, as well as with engines YaMZ-236, YaMZ-238, YaMZ-238A, YaMZ-238V, YaMZ-238G and YaMZ-238K, produced before August 1985.

Lubrication system

Mixed. Under pressure, the main and connecting rod bearings of the crankshaft, camshaft bearings, bushings of the upper heads of the connecting rods, bushings of rocker arms, bushing of the intermediate gear of the oil pump, spherical bearings of the rods, bushings of pushers are lubricated.

High pressure fuel pump and speed control are equipped with circulating lubrication from the engine lubrication system

Oil pump - gear, two-section

Gears, rolling bearings and camshaft lobes are splash lubricated.

Oil system pressure, kPa (kgf/cm2) for all engines:

  • - at nominal speed - 400-700 (4-7)
  • - at minimum idle speed, not less than 100 (1.0)

Oil cooling system - oil cooler mounted outside the engine

Oil filters

Two - full-flow, with a replaceable filter element and fine cleaning - centrifugal, with a jet drive. It is allowed to install a coarse filter instead of a full-flow one.

Opening pressure of lubrication system valves, kPa (kgf/cm2):

  • - oil pump pressure reducing valve 700-800 (7.0-8.0)
  • - safety valve of the radiator section of the oil pump 100-130 (1.0-1.3)
  • - differential valve 520-560 (5.2-5.6)
  • - bypass valve of the coarse oil filter 180-230 (1.8-2.3)
  • - full flow oil filter bypass valve 200-250 (2.0-2.5)

TECHNICAL DATA

SPECIFICATION

Lubrication system

Mixed. Under pressure, the main and connecting rod bearings of the crankshaft, camshaft bearings, bushings of the upper heads of the connecting rods, bushings of rocker arms, bushing of the intermediate gear of the oil pump, spherical bearings of the rods, bushings of pushers are lubricated.

High pressure fuel pump and speed control are equipped with circulating lubrication from the engine lubrication system

Oil pump - gear, two-section

Gears, rolling bearings and camshaft lobes are splash lubricated.

Oil system pressure, kPa (kgf/cm2) for all engines:

  • - at nominal speed - 400-700 (4-7)
  • - at minimum idle speed, not less than 100 (1.0)

Oil cooling system - oil cooler mounted outside the engine

Oil filters

Two - full-flow, with a replaceable filter element and fine cleaning - centrifugal, with a jet drive.

It is possible to install a coarse filter instead of a full-flow one.

Opening pressure of the lubrication system valves, kPa (kgf/cm2):

  • - oil pump pressure reducing valve 700-800 (7.0-8.0)
  • - safety valve of the radiator section of the oil pump 100-130 (1.0-1.3)
  • - differential valve 520-560 (5.2-5.6)
  • - filter bypass valve oil pre-cleaner 180-230 (1.8-2.3)
  • - full flow oil filter bypass valve 200-250 (2.0-2.5)

Power system

Fuel supply equipment - Separate type

Fuel priming pump - Piston, with manual priming pump

The high-pressure fuel pump of the YaMZ-236M2 engine is six-plunger.

The high-pressure fuel pump of YaMZ-238M2, YaMZ-238AM2, YaMZ-238VM, YaMZ-238GM2, YaMZ-238KM2 engines - eight-plunger

Plungers - Spool type, diameter 10 mm, stroke 11 mm

The order of operation of the fuel pump section of the YaMZ-236M2 engine: 1-4-2-5-3-6

The operating procedure of the fuel pump section of YaMZ-238M2, YaMZ-238AM2, YaMZ-238VM, YaMZ-238GM2, YaMZ-238KM2 engines: 1-3-6-2-4-5-7-8

Section numbering - drive side

Regulator speed - centrifugal, all-mode

Injection advance setting angle, degrees:

  • - for YaMZ-236M2, YaMZ-238M2, YaMZ-238AM2, YaMZ-238VM, YaMZ-238GM2 engines - 15°;
  • - for YaMZ-238KM2 engine - 10°

Advance clutch - automatic. centrifugal type

Nozzles - closed type, with multi-tier sprayers

Injection start pressure, MPa (kgf/cm2) - 22.6+0.8 (230+8)

Fuel filters

Two, coarse and fine filters with replaceable filter elements.

A bypass jet is installed in the cover of the fine filter

Air filter - inertial oil or dry type

Cooling system

Liquid, closed type, with forced circulation of the coolant; equipped with a thermostat to maintain a constant thermal regime of the engine

The water pump is centrifugal, driven by a V-belt from the crankshaft pulley

Fan - six-bladed, gear-driven

Electrical equipment

Generator - three-phase synchronous, alternating current, with built-in rectifier unit

Generator - on YaMZ-236M2, YaMZ-238M2, YaMZ-238AM2, YaMZ-238VM, YaMZ-238GM2 engines - G-273V2 or 1322.3771

YaMZ-238KM2 engine generator - 1702.3771

Rated rectified voltage, V - 28

Starter - 25.3708-01, direct current, series excitation, with electromagnetic drive

Rated starter power, kW, at C20=182Ah - 8.2

Grip

Engine model:

  • - YaMZ-236M2 - YaMZ-236K or YaMZ-181*;
  • - YaMZ-238M2 - YaMZ-238 or YaMZ-182*;
  • - YaMZ-238AM2, YaMZ-238VM, YaMZ-238GM2, YaMZ-238KM2 - YaMZ-238

Gearbox

Model:

  • - for YaMZ-236M2 engine - YaMZ-236P;
  • - for YaMZ-238M2, YaMZ-238AM2, YaMZ-238VM, YaMZ-238GM2, YaMZ-238KM2 engines - YaMZ-236N

Type - Mechanical, three-way, five-speed, with synchronizers in second-third and fourth-fifth gears

Gear ratios:

  • - first gear - 5.26
  • - second gear - 2.90
  • - third gear - 1.52
  • - fourth gear- 1.00
  • - fifth gear - 0.66
  • -reverse- 5.48

Weight of unfilled engine, kg:

Engine model

YaMZ-236M2

YaMZ-238M2

YaMZ-238AM2

YaMZ-238VM

YaMZ-238GM2

YaMZ-238KM2

without clutch and gearbox

890

-

1075

1075

1075

1075

with clutch without gearbox

-

-

-

1105

1170

-

with double disc clutch

and gearbox

1205

1390

1390

-

-

-

with single disc clutch

and gearbox

1185

-

-

-

-

-

Filling capacities, l

engine model

YaMZ-236M2

YaMZ-238M2

YaMZ-238AM2

YaMZ-238VM

YaMZ-238GM2

YaMZ-238KM2

Lubrication system

(no heatsink)

21

29

29

28

29

29

Cooling system

(no heatsink)

17

20

20

20

20

20

Air filter

1,4

0.85

0.85

0.85

Injection advance clutch

0.16

0.16

0.16

0.16

0.16

0.16

Gearbox

5.5

5.5

5.5

-

Cylinder numbering scheme

YaMZ-236/238 diesel cylinder numbering scheme

new

UAZ vehicles are equipped with three types of mechanical three-shaft gearboxes:

Maintenance of the K-126GU carburetor (for engines mod. 4178) The K-126GU carburetor is used to complete the 4178 model engines, as an option to replace the K-151V carburetor