VAZ-2123 petrol four-stroke, four-cylinder, eight-valve, inline, overhead camshaft

The order of operation of the cylinders: 1-3-4-2, counting — from the drive pulley of auxiliary units

Type of power system - distributed fuel injection

The engine is controlled by the BOSCH M7.9.7 controller (Euro-4 toxicity standards).

A catalytic converter is installed in the exhaust system.

On the right side of the engine (in the course of the car) there are: a receiver with a throttle assembly, a throttle position sensor and an idling regulator; an intake pipe and exhaust manifold; a fuel ramp with injectors; detonation and coolant temperature sensors of the control system; a thermostat; a coolant pump; a starter (mounted on the clutch housing); an air conditioner compressor (on an air-conditioned car).

On the left side of the engine there are: generator, power steering pump, spark plugs and high voltage wires, ignition coil, oil level gauge, oil filter, coolant temperature indicator sensors (in the instrument cluster) and insufficient oil pressure.

An air filter with a mass air flow sensor is fixed in the engine compartment to the left of the engine.

Front - drive auxiliary units (V-belt), crankshaft position sensor and phase sensor.

The engine with gearbox and clutch form a power unit mounted on three elastic rubber-metal supports.

Конструкция двигателя ВАЗ-2123

The engine cylinder block is cast from special low-alloy cast iron, the cylinders are wasted directly in the block.

The nominal diameter of the cylinder is 82.00 mm, the processing tolerance is + 0.05 mm. The estimated minimum clearance between the piston and the cylinder (for new parts) should be 0.025-0.045 mm.

It is defined as the size difference between the minimum diameter of the cylinder and the maximum diameter of the piston and is provided by installing a piston of the same class as the cylinder in the cylinder.

To do this, cylinders and pistons, depending on the dimensions obtained during machining, are divided into five classes after 0.01 mm.

The cylinder class according to its diameter is marked with Latin letters on the lower plane of the cylinder block: A - 82.00-82.01, B - 82.01—82.02, C — 82,02—82,03, 13 — 82,03—82,04, E — 82.04-82.05 mm.

During repair, the cylinder diameter can be increased by boring 04 or 08 mm for larger pistons. The maximum allowable wear of the cylinder is 0.15 mm per diameter.

In the lower part of the cylinder block there are five supports of the crankshaft main bearings with removable covers, which are attached to the block with special bolts.

The holes in the cylinder block for bearings are processed with the covers installed, so the covers are not interchangeable and are marked with risks on the outer surface to distinguish them.

On the end surfaces of the rear support there are sockets for thrust half-rings that prevent axial movement of the crankshaft.

A steel—aluminum half-ring (white) is installed in front, and a metal-ceramic (yellow) one is installed in the back. In this case, the grooves on them should be facing the crankshaft.

The half-rings are supplied in nominal and increased by 0.127 mm sizes.

If the axial clearance (backlash) of the crankshaft goes beyond 0.06-0.26 mm, then one or both half-rings must be replaced (the maximum permissible axial clearance of the crankshaft in operation is 0.35 mm).

Конструкция двигателя ВАЗ-2123

The inserts of the main and connecting rod bearings of the crankshaft are thin—walled steel-aluminum.

The upper liners of the main bearings of the first, second, fourth and fifth supports with a groove on the inner surface, and the upper liner of the third support and the lower liners installed in the covers are without a groove.

Repair inserts of main and connecting rod bearings are produced under the crankshaft necks, reduced by 0.25, 0.5, 0.75 and 1.00 mm.

The nominal design diametric clearance between the crankshaft necks and bearing liners should be:

- for main bearings - 0.026-0.073 mm (maximum allowable clearance - 0.15 mm);

- for connecting rod bearings - 0.02-0.07 mm (maximum allowable clearance - 0.1 mm).

The crankshaft is made of high-strength cast iron, has five main and four connecting rod necks.

The shaft is equipped with eight counterweights cast at the same time with the shaft (full-weight).

To supply oil from the root necks to the connecting rods, channels are drilled in it, closed with pressed and minted plugs.

These channels also serve for oil purification: under the action of centrifugal force, solid particles and resins that have passed through the filter are discarded to the plugs.

Therefore, when repairing the shaft and balancing, it is necessary to clean the channels from accumulated deposits.

The plugs cannot be reused — they are replaced with new ones.

At the front end (toe) of the crankshaft, a sprocket is mounted on the segment key, which drives the timing mechanism (timing), and the drive pulley of auxiliary units (generator, power steering pump and coolant pump), which is also a damper for torsional vibrations of the crankshaft.

In an air-conditioned car, the drive pulley of the air conditioner compressor is pulled to the drive pulley of the auxiliary units by the crankshaft nut.

A gear ring is made on the drive pulley of the auxiliary units for reading information by the crankshaft position sensor.

The crown has 58 teeth (the circumference of the crown is divided into 60 teeth, but two are missing, forming a depression — this is necessary to obtain a synchronization pulse at each revolution of the crankshaft).

On the outer cylindrical surface of the pulley, the front crankshaft oil seal is installed in the timing drive cover, cast from aluminum alloy.

The timing cover has a tide with a hole for the crankshaft position sensor. The rear oil seal is pressed into an aluminum alloy holder, which is attached to the rear end of the cylinder block.

The oil seal works on the surface of the crankshaft flange.

The front bearing of the primary shaft of the gearbox is pressed into the rear end of the crankshaft.

A flywheel is attached to the crankshaft flange with six bolts through a common washer.

It is cast from cast iron and has a pressed steel gear ring for starting the engine with a starter.

The flywheel is installed so that the cone-shaped hole near its crown is opposite the connecting rod neck of the 4th cylinder — this is necessary to determine the TDC after the engine assembly.

Конструкция двигателя ВАЗ-2123

Connecting rods - steel, I-section, processed together with the covers.

In order not to confuse the covers during assembly, the cylinder number is stamped on them, as well as on the connecting rods (it must be on one side of the connecting rod and the lid).

Special bolts are pressed into the holes of the lower head of the connecting rod; when disassembling, they cannot be knocked out of the head.

A steel-bronze sleeve is pressed into the upper head of the connecting rod.

According to the diameter of its hole for the piston pin, connecting rods are divided into three classes with a step of 0.004 mm (the same as pistons).

The class number is stamped on the upper head of the connecting rod.

Connecting rods are also divided into 9 classes by weight, which are marked with paint of different colors on the rods of the connecting rods.

All connecting rods of the engine must be of the same class by weight, i.e. marked with paint of the same color.

The piston pin is steel, tubular section, floating type (rotates freely in the piston bosses and in the connecting rod head), is fixed from falling out by two locking spring rings located in the grooves of the piston bosses.

According to the outer diameter, there are three classes of fingers (through 0.004 mm), which are marked with paint:

1 - blue (21,970-21,974 mm), 2 - green (21,974-21,978 mm), 3 - red (21,978-21,982 mm).

The piston is cast from aluminum alloy.

The piston skirt has a complex shape: in the longitudinal section it is barrel-shaped, and in the transverse section it is oval.

In the upper part of the piston there are three grooves for the piston rings.

The groove of the oil removal ring has drilling holes for the supply of oil collected by the ring from the cylinder walls to the piston pin.

The hole for the piston pin is displaced by 1.2 mm from the diametrical plane of the piston, therefore, when installing the piston, it is necessary to orient yourself by the knocked-out arrow on its bottom: it should be directed towards the crankshaft pulley.

According to the outer diameter (nominal size), pistons are divided into 5 classes: A - 81.965-81.975, B - 81.975—81.985, C - 81.985-81.995, D - 81.995-82.005, E - 82.005-82.015 mm. The piston class is branded with a letter on its bottom.

For pistons of repair sizes, a triangle (an increase in diameter by 04 mm) or a square (an increase in diameter by 0.8 mm) is knocked out on the bottom.

The spare parts are supplied with pistons of three classes — A, C and E (nominal and repair sizes), which is quite enough for the selection of the piston to the cylinder. At the same time, it is not recommended to install a new piston in a worn cylinder without boring the cylinder.

The groove under the upper piston ring in the new piston may be slightly higher than in the old one, and the ring will break on the "step" formed in the upper part of the cylinder during its wear.

According to the diameter of the hole for the piston pin , the pistons are divided into 3 classes: 1-21,982-21,986, 2 — 21,986—21,990,

3 — 21,990—21,994 mm. The class number is also stamped on the bottom of the piston. For new parts, the class of finger holes in the connecting rod and piston must be identical to the class of the finger.

The pistons of the engine are produced of the same class by weight, so they do not need to be selected separately.

Конструкция двигателя ВАЗ-2123

The piston rings are located in the grooves of the piston.

The two upper rings are compression rings. They prevent the breakthrough of gases into the crankcase of the engine and remove heat from the piston to the cylinder.

The lower piston ring is oil—removable. The nominal height gap between the piston rings and the grooves in the piston (measured by a set of probes) should be:

for the upper compression ring — 0.04—0.07 mm; for the lower - 003-006 mm: for the oil- 0.02-0.05 mm.

The maximum permissible gaps during wear are 0.15 mm. The gap in the lock for all piston rings should be 0.25-0.45 mm.

The gap is measured with a set of probes, inserting the ring into a special caliber or into the engine cylinder and aligning it with the bottom of the piston.

The cylinder head is made of aluminum alloy, common to all four cylinders. It is centered on the cylinder block by two bushings and fastened with 11 bolts.

If the length of the bolt rod exceeds 117 mm, then it should be replaced with a new one.

A non-shrink metal-reinforced gasket is installed between the block and the head. Repeated use of the gasket is not allowed.

In the upper part of the cylinder head, an aluminum housing of camshaft bearings is fixed on nine studs.

It is centered on two bushings worn on the extreme studs. The gap between the camshaft necks and the housing supports should not exceed 0.2 mm.

The camshaft is cast iron with bleached cams, five-support; driven by a single-row roller chain from the crankshaft sprocket.

Axial movement is limited by a thrust flange entering the groove of the front support shaft neck.

There are marks on the sprockets for the correct installation of the valve timing phases. In this case, the mark on the crankshaft sprocket must coincide with the protrusion on the cylinder block, and the mark on the camshaft sprocket must align with the protrusion on the bearing housing.

The camshaft sprocket is mounted on the shaft in only one position and is tightened by a bolt with a support and locking washers.

The tendril of the latter enters the hole in the sprocket, and the side part bends to the edge of the bolt head. A metal element is riveted to the sprocket — the setpoint of the phase sensor.

The valve seats and guide bushings are cast iron, pressed into the cylinder head.

Repair bushings with an outer diameter increased by 0.2 mm are supplied to the spare parts.

The holes in the bushings are finally processed by scanning after pressing.

The diameter of the inlet valve bushings is 8,022—8,040 mm, exhaust — 8,029-8,047 mm.

Grooves for lubrication are cut on the inner surface of the sleeve: at the inlet valve sleeve — for the entire length, at the outlet - up to half the length of the hole.

Metal-rubber oil-reflecting caps (valve seals) with a bracelet steel spring are put on top of the bushings.

The gaps between the new guide bushings and valve rods should be within 0.022-0.055 mm for intake valves and 0.029—0.062 mm for exhaust valves (the maximum gap for wear during operation is 0.3 mm).

Valves — steel; exhaust - with heat-resistant steel heads, with fused chamfers.

The valves are arranged in a row, obliquely to the plane passing through the axes of the cylinders.

The diameter of the intake valve plate (37 mm) is larger than the exhaust (31.5 mm).

The valves are driven from the camshaft cams via levers ("rockers").

The gaps in the valve actuator are not adjustable. One end of the lever rests on the spherical head of the hydraulic support (hydraulic gap compensator), and the other acts on the end of the valve stem.

INA hydraulic supports are installed on the engine, which differ in design from the hydraulic supports used earlier.

A steel sleeve (housing) is first screwed into the cylinder head, and a support is inserted into it on a sliding landing. With this method of assembly, the possibility of deformation of a precision pair of hydraulic supports is excluded.

To supply engine oil under pressure to the hydraulic supports, four aluminum spacers are installed between the hydraulic support housings and the cylinder head — one spacer for the hydraulic supports of two valves of each cylinder.

Through the channel of the cylinder block and the block head, oil flows to the camshaft bearing housing, and then through a tubular steel ramp to the spacers of the hydraulic valves.

The connections of the ramp tubes with spacers are sealed with rubber bushings.

The use of INA hydraulic supports entailed the use of new valve levers, which reduced the diameter of the support sphere from 12 mm (for the previous levers) to 11 mm.

The valve closes under the action of two springs with opposite winding installed coaxially (coaxially).

With their lower ends they rest on the support washers, and with their upper ends they rest on a plate, which is fixed with two cone crackers entering the groove at the end of the valve stem.

To reduce the oscillations of the timing chain on its left branch, a plastic calming device is installed on two bolts between the sprocket of the oil pump drive roller and the camshaft sprocket.

The right branch of the chain is stretched by a spring-hydraulic tensioner installed in the cylinder head.

The pre-tension of the chain (on an idle engine) is provided by a spring, the working one (after starting the engine) is provided by a pressure oil backup.

The oil is fed into the hydraulic tensioner through a steel one-piece tube with a diameter of 6 mm with tips. This line starts from the threaded hole on the left wall of the cylinder block, into which the fitting of the emergency oil pressure sensor is screwed.

Properly selected bending stiffness of the tube allowed to weaken its vibrations, besides metal holders with rubber inserts are used, suppressing vibration.

The tip of the tube is attached to the body of the tensioner by means of a bolt-fitting, which is used to attach the hose of the front brake mechanism of cars of rear and all-wheel drive VAZ families.

The tensioner plunger presses on the shoe, made, like the chain restorer, of wear-resistant plastic.

The tensioner shoe rotates on the axis located at the bottom of the cylinder block, to the right of the crankshaft sprocket.

The oil pump drive roller is also driven from the gas distribution mechanism chain.

The fastening of its sprocket (30 teeth) is similar to the fastening of the camshaft sprocket (38 teeth).

The roller rotates in the bushings located in the cylinder block, and is kept from axial movements by a thrust flange entering the groove on its front neck.

The gear ring of the roller engages with the gear of the oil pump drive mounted vertically in the cylinder block sleeve.

The gear has a longitudinal hole with slots, into which the spline shank of the oil pump roller enters from below.

Oil pump — gear, single-stage, with a reduction valve; mounted in a housing fixed at the bottom of the cylinder block.

The intake pipe is cast at the same time with the lower part of the housing and is closed with a stamped mesh for rough cleaning of oil from mechanical impurities.

Nominal clearances in the oil pump should be:

- between the teeth of the gears - 0.15 mm (maximum permissible value - 0.25 mm);

- between the gears (in outer diameter) and the walls of the pump housing - 0.11-0.18 mm (maximum permissible value - 0.25 mm);

- between the ends of the gears and the plane of the housing - 0.066-0.161 mm (maximum permissible value - 0.20 mm);

- between the driven gear and its axis - 0.017-0.057 mm (maximum permissible value - 0.10 mm);

- between the pump shaft and the hole in the housing - 0.016-0.055 mm (the maximum permissible value is 0.10 mm).

Engine lubrication is combined.

Under pressure, oil is supplied through a filter to the crankshaft root and connecting rod bearings, hydraulic supports of valve levers, hydraulic chain tensioner, camshaft bearings and the oil pump drive roller sleeve.

By spraying, oil is supplied to the cylinder walls (further to the piston rings and fingers), to the cam cam — lever pairs, chains and valve rods.

The oil filter is full—flow, non-removable, with bypass and anti-drainage valves.

The crankcase ventilation system is closed, forced. Under the action of rarefaction in the intake pipeline of a running engine, gases from its crankcase through the oil separator enter the intake tract through hoses of two circuits.

Through the hose (larger diameter) of the main circuit, crankcase gases are discharged in partial and full engine operation modes into the space in front of the throttle valve.

Through the hose of the idling circuit, crankcase gases are discharged into the space behind the throttle valve both in partial and full engine load modes and in idle mode.