The KAMAZ-740.50-360 and KAMAZ-740.51-320 engines are designed for installation in single vehicles and road tractors used in road trains, supplied to the domestic market and to countries with temperate and tropical climates, as well as supplied as spare parts.
Engines manufactured in the «U» version according to GOST 15150-69 are designed for operation at ambient temperatures from minus 45 to plus 40 °C, relative air humidity up to 75 % at a temperature of 15 °C and in areas located at an altitude of up to 3000 m above sea level, with a reduction in power, economic and other indicators of up to 20 %, with the negotiation of passes up to 4500 m.
Engines manufactured in the «T» version according to GOST 15150-69 are designed for operation at ambient temperatures from minus 10 to plus 45 °C, relative air humidity up to 80 % at a temperature of 27 °C and in areas located at an altitude of up to 3000 m above sea level, with a reduction in power, economic and other indicators of up to 20 %, with the negotiation of passes up to 4500 m.
The general view, longitudinal and transverse sections of the engines are shown in Figures 1–5.
The engines are four-stroke compression-ignition, liquid-cooled, with a V-shaped arrangement of eight cylinders, with turbocharging and charge air intercooling (CAC) of the «air-to-air» type.
In terms of harmful substance emissions with exhaust gases, the 740.50-360 and 740.51-320 engines comply with the requirements of the UNECE regulations (EURO-2).
The base component of the engines is the cylinder block, on which the engine assemblies and parts are mounted and secured.
«Wet» type cylinder liners are installed in the bore of the half-blocks.
On top, the cylinder liners are closed by heads, separate for each cylinder. From below, the cylinder block is closed by a stamped oil sump.
In the cylinder block, the camshaft is located on five plain bearings. The crankshaft is installed in the lower part of the block.
The engine cooling system is liquid, closed type, designed for the use of antifreeze coolant.
Technical characteristics of the 740.50-360, 740.51-320 engine
| Parameter | Value |
|---|---|
| Engine type | Four-stroke, compression-ignition |
| Cylinder arrangement | V-shaped, with a 90° angle |
| Firing order | 1-5-4-2-6-3-7-8 |
| Crankshaft rotation direction | right (anticlockwise, viewed from the flywheel side) |
| Cylinder diameter and piston stroke, mm | 120×130 |
| Displacement, l | 11.76 |
| Rated power, kW (hp) | 265 (360); for the 740.51-320 engine: 235 (320) |
| Maximum torque, N·m (kgf·m) | 1470 (150); for the 740.51-320 engine: 1275 (130) |
| Injection advance angle, degrees | 9 + 1 |
| Compression ratio | 16.8 (±2) |
| Crankshaft speed, min-1 | rated: 2200 ± 50; at maximum torque: 1300–1500 |
| Crankshaft idle speed, min-1 | minimum: 600 ± 20; maximum: 2530-80 |
| Number of valves in the cylinder head | 2 (intake and exhaust) |
| Clearances on a cold engine between rocker arms and valve stems | intake: 0.25–0.30 mm; exhaust: 0.35–0.40 mm |
| Oil pressure in a warm engine, kPa (kgf/cm²) | at rated speed: 392–539 (4–5.5); at minimum idle, not less than: 98 (1) |
| Injector, type | 273.1112010-20 (273-20) |
| Nozzle | «YAZDA» model 273.1112010-20 or 273.1112010-50 (273-50); or «BOSCH» DLLA148S1380 |
| Injector opening pressure, MPa (kgf/cm²) | 23.73–24.90 (242–254) |
| High-pressure fuel pump (HPFP) | model 337-20.04; for the 740.51-320 engine: 337-20.03 |
| Boost system | gas turbine with two turbochargers and «air-to-air» CAC |
Generators
- Generator model G-273V or 6582.3701 (in accordance with design documentation) — three-phase synchronous, alternating current, with built-in rectifier block.
- Generator G-273V:
- rated current, A: 28;
- rated rectified voltage, V: 28;
- rated power, kW: 0.8.
- Generator mod. 6582.3701:
- rated current, A: 75;
- rated rectified voltage, V: 28;
- rated power, kW: 2.0.
Starter
Starter 5662.3708, direct current, series excitation, with electromagnetic drive. Rated power, kW: 8.2.
Gearbox
- Gearbox model 161, mechanical, eight-speed;
- Or gearbox model ZF-16S151 from «ZAHNRADFABRIK», mechanical, sixteen-speed, comprising a main four-speed gearbox with an integrated two-speed splitter located in front of the main gearbox, and a two-speed planetary range-change unit located behind the main gearbox.
Possible faults and methods of remedy
Engine
The engine does not start:
- No fuel in the tank — fill the fuel tank, bleed the fuel supply system.
- Air in the fuel supply system — eliminate the leak, bleed the system.
- Incorrect adjustment of the injection advance angle — adjust the angle.
- Freezing of water that has entered the fuel pipes or the strainer of the fuel tank intake — carefully warm the fuel filters, pipes and tank with a cloth moistened with hot water or steam. Do not use an open flame for heating.
The engine does not develop the required power, runs unevenly, smokes:
- Clogging of the air cleaner or air intake cap — carry out maintenance of the air cleaner or clean the cap strainer.
- Insufficient fuel supply — replace the fine fuel filter elements, wash the coarse filter, tighten the connections in the fuel pipes.
- Incorrect adjustment of the injection advance angle — adjust the angle.
- Clogging of the injector (coking of the nozzle holes, sticking of the needle) or incorrect adjustment — wash the injector, if necessary replace the nozzle, check and if necessary adjust.
- Incorrect adjustment of the governor control lever drive (the control lever does not reach the maximum crankshaft speed limit bolt) — check and adjust the governor drive.
- Breakage of the HPFP tappet spring — replace the spring and adjust the pump on the test bench.
- Ingress of dirt between the seat and valve of the fuel priming pump or breakage of the spring — wash the valve or replace the spring, check the pump operation on the test bench.
- Leakage of the HPFP delivery valves or breakage of the spring — eliminate the valve leakage in the workshop or replace the spring.
- Seizing of the HPFP section plunger — replace the plunger pair and adjust the pump.
- Incorrect adjustment of the thermal clearances in the valve timing mechanism — adjust the clearances.
- Depressurisation of the diaphragm cavity or damage to the diaphragm of the boost pressure corrector — restore the tightness of the diaphragm cavity or replace the damaged diaphragm.
- Cessation of oil supply to the boost pressure corrector — restore the oil supply to the corrector.
- Loosening of the fastening or breakage of the high-pressure pipe — tighten the fastening nut or replace the pipe.
- Poor compression due to faults in the piston group or loose seating of the valve timing valves on their seats — check the condition of the pistons and piston rings, grind in the valves.
- Thickening of the fuel (in cold weather) — replace the fine fuel filter elements, replace the fuel with the one corresponding to the season, bleed the fuel supply system.
Low boost air pressure:
- Air leakage through the connections of the intake manifold with the cylinder heads, pipes, turbochargers and compressor — tighten the connections, if necessary replace the gaskets and connecting hoses.
- Blow-by of gases in the connections of the exhaust manifold and turbine housing — tighten the connections, if necessary replace the gaskets.
- Seizing of the turbocharger rotor — replace the turbocharger.
- Contamination of the exhaust tract, flow parts of the compressor and turbine — clean the pipelines, remove the turbocharger and remove deposits from the flow parts.
Extraneous noise in the turbocharger:
- Rotor rubbing against housing parts — tighten the fastening bolts of the turbine and compressor housings. Check for absence of rotor rubbing in its extreme positions. If the rotor rubs, replace the turbocharger. If the noise does not disappear, remove the turbocharger for maintenance.
High-frequency noise (whistling):
- The tightness of the intake and exhaust tracts of the engine is broken — tighten the bolts and nuts of the fastening of the system parts, if necessary replace the gaskets.
Increased oil consumption:
- Prolonged operation of the engine at idle — do not run the engine at idle unnecessarily.
- Oil leakage through the connections in the lubrication system of the turbocharger — tighten the connections, if necessary replace the gaskets and rubber hoses.
- Wear of the valve — guide pairing in the cylinder head, ageing of the rubber valve seal — check and replace the worn parts.
- Clogging of the air cleaner or air intake cap — carry out maintenance of the air cleaner and clean the cap strainer.
Decrease in oil pressure in the lubrication system:
- Low oil level in the oil sump — check and if necessary add oil up to the «B» mark.
- Fault of the pressure control instruments — make sure the instruments are in good order.
- Use of oil of an unsuitable viscosity — replace the oil with the one corresponding to the chemotological chart.
- Contamination of the filter elements of the oil filter — replace the filter elements.
- Incorrect adjustment or seizing of the safety valve or lubrication system valve — check the valves and eliminate the seizing, if necessary adjust or replace the faulty parts.
- Clogging of the oil pump intake — wash the intake.
- Coolant entering the oil — check the tightness of the water cavity, the sealing of the cylinder liners, the tightness of the water-oil heat exchanger, replace the faulty parts.
- Oil leaks at the connection points and in the oil lines of the lubrication system — check the condition of the technological plugs, drain plugs, the tightening of the fastening parts at the connection points, the condition of the sealing rings and gaskets.
- Fault in the operation of the oil pump — remove the pump and check its operation on a special test bench.
- Unacceptable increase in the clearance in the bearings of the crankshaft and camshaft — repair the engine.
Illumination of the emergency oil temperature indicator:
- Fault of the emergency oil temperature sensor — make sure the sensor is in good order, if necessary replace it.
- Seizing of the thermovalve for switching on the heat exchanger, fault of the thermopower sensor — check the operation of the thermovalve for switching on the heat exchanger, if necessary eliminate the seizing or replace the sensor.
- Clogging of the tubes or contamination of the cooling plates — check the water-oil heat exchanger for clogging of the tubes and contamination of the cooling plates, if necessary wash or replace the heat exchanger.
Increase in oil pressure in the lubrication system:
- High viscosity of the oil — replace the oil with the one corresponding to the chemotological chart.
- Leakage of the control signal line connecting the main oil line with the pump, or its clogging — check the oil supply pipe to the pump, the tightening of the fastening bolts, the presence of a hole in the cover.
- Seizing or incorrect adjustment of the lubrication system valve — check the valve and eliminate the seizing, if necessary replace the faulty parts.
Knocking during engine operation:
- Early injection of fuel into the cylinders — adjust the injection advance angle.
- Excessive thermal clearances in the valve timing mechanism — adjust the clearances.
- Seizing of the valve timing mechanism valves in the guides (the piston touches the valve) — disassemble and wash the valve mechanism. If necessary replace the valve.
- Excessive cyclic fuel supply (the rack retainer has come out of engagement) — replace the HPFP rack.
Dull knocking of the crankshaft. The frequency increases with an increase in crankshaft speed:
- Unacceptable increase in the clearance between the journals and the main bearing shells as a result of the use of oil not corresponding to the specified one, or a decrease in pressure and oil supply — grind the journals to the repair size and replace the shells, replace the oil and check the operation of the oil pump.
- Unacceptable increase in the clearance between the thrust half-rings and the crankshaft — replace the thrust half-rings with new ones of greater thickness.
- Loosening of the tightening of the bolts fastening the flywheel to the crankshaft — determine the cause and tighten the bolts.
Knocking of the connecting rod bearings is sharper than the knocking of the main bearings. It is heard when the engine is idling and intensifies with an increase in crankshaft speed:
- Unacceptable increase in the clearance between the journals and the connecting rod bearing shells as a result of the use of oil not corresponding to the specified one, or a decrease in pressure and oil supply — grind the journals to the repair size and replace the shells, change the oil and check the operation of the oil pump.
Dull knocking of the pistons, caused by the pistons striking the cylinders. It is heard at low crankshaft speed and under load:
- Unacceptable increase in the clearance between the pistons and the cylinders — replace the pistons and, if necessary, the cylinder liners.
- Severe wear of the ends of the piston rings and the corresponding grooves on the piston — replace the piston rings and, if required, the pistons.
Knocking of the piston pins, double, metallic, sharp, caused by excessive clearance. It is best heard at engine idle:
- Unacceptable increase in the clearance between the pin and the bushing of the upper connecting rod head — replace the pin and, if necessary, the connecting rod.
Increased temperature of the liquid in the cooling system*:
- Weak tension or breakage of the water pump drive belts — tighten or replace the belts.
- Fault of the thermostats — replace the thermostats.
- Contamination of the radiator core — clean the radiator core of dirt.
Increased coolant consumption:
- Damage to the radiator — eliminate the damage or replace the radiator.
- Leakage of liquid through the face seal of the water pump — replace the face seal.
- Coolant entering the lubrication system through the rubber sealing rings of the cylinder liners or through the rubber gaskets of the cylinder heads — replace the sealing rings of the cylinder liners or the rubber gaskets.
* Before looking for the cause of the fault in the lubrication system and cooling system, it is necessary to make sure that the oil pressure and temperature indicators are in good order.
Electric flame device (EFD)
The EFD glow plug is faulty, the 30A fuse link burns out:
- Short circuit of the thermal relay spiral or electrical wires.
If the glow plugs are in good order, disconnect from the thermal relay the wire connecting it to the EFD switch-on button.
The absence of a short circuit when the EFD is switched on again indicates a short circuit of the thermal relay spiral. In this case, the thermal relay should be replaced.
If the thermal relay spiral is intact (determined by touch) and a short circuit occurs with the wires disconnected from the glow plugs, this indicates a short circuit of the electrical wires. Eliminate the short circuit.
- Short circuit of the glow plug to earth.
Disconnect the wire from the terminal of the left glow plug, excluding contact of the tip with earth, and switch on the EFD again. In case of a short circuit, disconnect the wire from the terminal of the right glow plug.
The absence of a short circuit indicates a short circuit of the right glow plug. Replace the failed glow plug.
After eliminating the short circuit, it is recommended to check the condition of the insulation of the electrical wires, the operation of the thermal relay and the EFD switch-on relay, and if the short circuit occurred when starting the engine — the operation of the shunt relay.
The EFD does not work, no voltage is supplied to the EFD:
- Burning out of the thermal relay spiral — switch on the EFD and check the voltage at the thermal relay terminals. The absence of voltage at the terminal on the side of the plug connection while there is voltage at the other terminal indicates that the spiral has burnt out. Replace the thermal relay.
- Burning out of the glow plugs or lack of contact in the circuit — switch on the EFD and check whether there is voltage at the terminals of each EFD product, starting with the flame glow plugs. The presence of voltage at the terminal of the right glow plug indicates that the glow plugs have burnt out. Replace the glow plugs or restore the contact.
- Burning out of one of the glow plugs — switch on the EFD for 10–15 s, then replace the cold glow plug.
No flame of the glow plug:
- No fuel supply to the glow plug — loosen the fuel supply union on the glow plug. Switch on the EFD and, after the indicator lights up (opening of the solenoid valve), turn the crankshaft with the starter. If the fuel, with the valve open, does not seep through the loosely tightened threaded connection of the union, eliminate the fault in the fuel supply system.
- Fuel not passing through the glow plug — unscrew the glow plug from the manifold. Wash and blow with compressed air the jet, the fuel filter and the fuel supply cavities.
Check for the presence of a flame, for which purpose:
- connect the fuel pipe and electrical wires to the glow plug;
- ensure a reliable connection of the glow plug body with earth and make sure that the terminal is insulated from earth;
- switch on the EFD and turn the crankshaft with the starter.
If there is no flame, replace the faulty glow plug.
Electrical equipment
The charge circuit warning lamp is on at the rated crankshaft speed of the engine:
- Loosening of the tension of the generator drive belts — adjust the belt tension.
- Contamination of the slip rings — wipe the rings with a cotton cloth moistened with pure petrol. If the contamination is not removed, clean with glass paper and wipe again with the cloth.
- Wear or sticking of the brushes in the brush holders — check the height of the brushes, their free movement in the brush holder channels and the force of the springs; if required, replace the brush holder or the brushes.
- Breakdown of the rectifier block — replace the block.
- Short circuit of the stator winding — replace the stator assembly.
- Fault in the excitation circuit — check the serviceability of the excitation circuit.
- Wear of the bearing parts or their destruction — replace the generator.
- Deformation of the generator fan — straighten the bent places.
Overheating of the bearings:
- Excessive tension of the belts — adjust the belt tension.
Excessively rapid wear of the generator brushes:
- Contamination of the slip rings — wipe the rings with a cotton cloth moistened with pure petrol. If necessary, clean with glass paper and wipe again with the cloth.
- Radial runout of the slip rings — check the radial runout of the rings. If required, turn the slip rings.
Excessively high charging current:
- Short circuit in the brush assembly of the generator or in the circuit between the generator and the regulator — eliminate the short circuit.
- Fault of the voltage regulator — replace the regulator.
- Fault of the relay for disconnecting the generator excitation winding — replace the relay.
Increased noise level during generator operation:
- Loosening of the pulley fastening — tighten the nut.
- Lack of contact between the brushes and the commutator — wipe the commutator with a clean cloth moistened with petrol, or clean it. Clean the brushes or replace them with new ones. Check the condition of the brush springs and replace them if faulty. Check whether the brushes stick in the brush holders.
Starter
The starter does not work:
- Short circuit or break in the pull-in winding of the traction relay — replace the relay.
- Break or lack of contact in the power supply circuit — find the place of damage and restore the contact.
- Sticking of the brushes — remove the brush holder, take out the brushes and remove the deposit of brush dust.
- Failure of the starter relay (738.3747-20) — replace the relay.
- Break in the circuit inside the starter — check and eliminate the defects of the starter or replace the starter.
The engine crankshaft does not turn with the starter (the traction relay operates):
- Discharge of the storage batteries — charge the batteries.
- Fault in the battery charging circuit — eliminate the fault.
- Fault of the voltage regulator — replace the regulator.
- Oiling or contamination of the brush-commutator assembly — clean the commutator and brushes from oil, dirt, copper-graphite dust.
- Poor contact of the starter housing with the earth of the power unit — ensure the reliability of the connection.
- Use of oil not corresponding to the season — replace the oil.
After starting the engine, the armature continues to rotate:
- Fault of the traction relay — replace the relay.
- Welding of the contacts of the starter relay (738.3747-20) — replace the relay.
When the starter is switched on, the traction relay does not operate (no characteristic click):
- Discharge of the storage battery — charge the battery.
- Break in the pull-in winding of the traction relay — replace the relay.
- Fault of the instruments and starter switch — replace the switch.
- Break or short circuit of the winding of the starter relay (738.3747-20) — replace the relay.
The starter armature rotates but does not turn the crankshaft:
- Breakage of the teeth of the flywheel ring gear or the gear wheel — replace the flywheel ring gear or the drive gear wheel.
- Fault in the starter adjustment — adjust the starter.
- Fault of the drive — replace the drive.
When the starter is switched on, repeated clicks of the traction relay and impacts of the drive gear wheel against the flywheel ring gear are heard:
- Unreliable contact of the circuit of the starter traction relay — check the contact connections and eliminate the fault.
- Fault of the hold-in winding of the traction relay — replace the traction relay.
- Fault of the winding or contact connection of the starter relay (738.3747-20) — replace the relay.
When the starter is switched on, a noise (grinding) of the drive gear wheel is heard:
- Installation of the starter with misalignment — install the starter correctly.
- Incorrect adjustment of the moment of closing of the traction relay contacts — adjust the clearance between the gear wheel and the thrust washer at the moment of switching on the starter.
The drive gear wheel systematically does not engage with the flywheel ring gear while the relay operates normally:
- Presence of burrs on the ends of the teeth of the flywheel or the drive gear wheel — file and clean the burrs on the teeth of the flywheel ring gear or the drive gear wheel.
- Wear of the ends of the teeth of the flywheel ring gear or the drive gear wheel — replace the flywheel ring gear or the drive gear wheel.
