Subaru Legacy/Outback

1999-2003 of release

Repair and operation of the car



Subaru of Legasi, Autbek
+ Cars Subaru Legacy, Outback
+ Operation manual
+ Routine maintenance
- Engine
   Specifications
   Check of compression pressure in cylinders and tightness of the block
   Diagnostics of a condition of the engine with use of the vacuum gage
   The engine lubrication system - the general information
   + the repair Procedures which are not connected with extraction of the engine from the car - four-cylinder engines
   + the repair Procedures which are not connected with extraction of the engine from the car - six-cylinder engines
   + General and capital repairs of engines
+ Cooling systems, heating
+ Power supply system and release
+ Electric equipment of the engine
+ Manual box and differential
+ Automatic transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment




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Engine

General information

Scheme of an arrangement of the main components of the 4-cylinder opposite SOHC engine

1 — the Camshaft
2 — the Inlet valve
3 — the Block of cylinders
4 — the Rod
5 — the Spark plug
6 — the Cover of camshafts
7 — GRM Cover

8 — the Head of cylinders
9 — the case Pallet
10 — the Final valve
11 — the Yoke of the drive of the final valve
12 — the Axis of yokes of the drive of the final valve
13 — the Axis of yokes of the drive of the inlet valve
14 — the Yoke of the drive of the inlet valve


Design of a head of cylinders of the 4-cylinder opposite SOHC engine

1 — the Inlet valve
2 — the Inlet channel
3 — turbulence Area
4 — the Combustion chamber

5 — the Final channel
6 — the Final valve
7 — the Spark plug


Design of camshafts of the 4-cylinder opposite SOHC engine

1 — Bearing necks
2 — Maslotoki

3 — Persistent flanges

Design of components of a head of cylinders of the 6-cylinder opposite DOHC engine

1 — Inlet port
2 — the Inlet valve
3 — the Final valve

4 — Final port
5 — the Combustion chamber


Design of camshafts of the 6-cylinder opposite DOHC engine

1 — Bearing necks
2 — Maslotoki
3 — Persistent flanges
4 — the Flange of the sensor of provision of a camshaft (CMP)

a — the Right inlet camshaft
b — the Right final camshaft
with — the Left inlet camshaft
d — the Left final camshaft


In this Chapter the device and procedures of service of engines of two types is described: with one (SOHC) or two (DOHC) camshafts of the top arrangement for each of heads of cylinders.

4-cylinder engines 2.0 and 2.5 of l

On models 2.0 and 2.5 of l 4-cylinder opposite petrol engines which are horizontally installed in forward part of the car are installed. These 4-stroke engines with liquid cooling and one (on a head) a camshaft of the top arrangement (SOHC) are supplied with the 16-valvate mechanism of gas distribution and made mainly of an aluminum alloy. Fuel moves in the engine by method of the distributed injection (MFIS).

Block of cylinders

The block of cylinders is made of an aluminum alloy by a molding method under pressure and supplied with the pig-iron sleeves of cylinders of dry type which are filled in in unit semi-blocks.

The structure of the cast block of cylinders allows to provide effective heat removal and gives it high durability with rather small weight.

The cranked shaft is established in five radical bearings of the increased durability the fifth of which is persistent and limits the size of an axial side play of a shaft.

 


Installation sites of radical bearings of a cranked shaft are developed in such a way that sufficient rigidity at a minimum level of a working noise background is provided.

The oil pump is located on the center in forward part of the block of cylinders, the water pump of the cooling system – in forward part of the left semi-block. In back part of the right semi-block the oil separator catching the oil suspension containing in karterny gases is established.

Heads of cylinders

Heads of cylinders are made of an aluminum alloy by a molding method under pressure.

The head of cylinders forms combustion chambers of tent type with the central arrangement of spark plugs and four valves (two inlet and two final) on the cylinder. Inlet and final valves are located on the different parties of the cylinder.

The central placement of spark plugs in combustion chambers promotes the distribution of turbulences increasing efficiency of combustion of air and fuel mix.

At the expense of an opposite arrangement of inlet and final valves the cross and line scheme of gas distribution is realized.

Metal laying of a head of cylinders is created from steel corrosion-proof sheets and has the three-layer design differing in the increased heat resistance and the providing reliability of sealing of a joint of the interfaced surfaces for a long time.

The drive of camshafts of the left and right heads of cylinders is carried out by means of one gear belt which is also used for the drive of the water pump located in the left semi-block of the power unit. Adjustment of a tension of a gas-distributing belt is made by the automatic regulator of a tension that excludes need of manual adjustments.

The camshaft keeps in a head of cylinders on four necks.

Two persistent flanges limit the size of an axial side play of each of camshafts.

The maslotok providing supply of greasing and cooling of the GRM components are provided in axial part of shaft.

In yokes of the drive of valves the screw and a nut intended for correction of valvate gaps are built in.

6-cylinder engines of 3.0 l

Models of 3.0 l are equipped with the 6-cylinder petrol engine of an opposite design which is horizontally installed in forward part of the car. These 4-stroke engines with liquid cooling and two (on a head) camshafts of the top arrangement (DOHC) are supplied with the 24-valvate mechanism of gas distribution and made mainly of an aluminum alloy. Fuel, as well as on 4-cylinder engines, moves by method of the distributed injection (MFIS).

Level of the vibrations made by opposite 6-cylinder engines, considerably below than at engines of a V-shaped design (V6). Besides, the similar design at high compactness allows to organize good dynamic balancing. Decrease in the noise background arising during the operation of the engine is helped by also following constructive decisions:

· The cranked shaft is established in seven radical bearings of the increased durability and has diameter of 64.0 mm that is 4 mm more, than on the previous models;
· Chains of the GRM drive are equipped with the hydraulic regulator of a tension and closed by a cover;
· The pallet of a case made of an aluminum alloy increases rigidity of a joint of the left and right semi-blocks, giving thereby additional durability to the zones forming beds of radical bearings of a cranked shaft;
· The engine is connected to transmission by more rigid 11-bolted connection in comparison with 8-bolted connection used in the previous models.

Use of the chain drive of camshafts which is not needing service allowed to reduce the full length of the power unit.

One more distinctive feature of 6-cylinder opposite engines used on the Subaru Legacy models is the low level of the content in the fulfilled gases of toxic components.

Block of cylinders

The block of cylinders is made of an aluminum alloy by a molding method under pressure, supplied with pig-iron sleeves of cylinders of dry type and differs in the low weight and the increased compactness:

· Length of the cylinder makes 98.4 mm that is much less than length of cylinders of 4-cylinder engines (113 mm);
· The ratio of the sizes of length of the cylinder and a piston stroke is chosen optimum from reasons of development of necessary power at the compact sizes of the power unit, components respectively 89.2 mm and 80.0 mm (in comparison with 92 mm and 75 mm for 4-cylinder engines of 2.0 l);
· The block of cylinders consists of two semi-blocks, in each of which is located on three cylinders. The efficiency of heat-removing ability provided with development and openness of a surface of semi-blocks allows to refuse need of the organization of the cooling channels connecting cylinders.

Each of semi-blocks is equipped with the independent cooling contour. Water shirts round sleeves of cylinders are open from heads (the open scheme) that considerably increases efficiency of cooling of components.

The cranked shaft is installed in 7 radical bearings the seventh of which is persistent.

 

The special form of the top part of the pallet of the case made of an aluminum alloy promotes suppression of considerable fluctuations of level of oil and, besides, forms part of contours of greasing and cooling, and also spiral chamber of the water pump and the camera of the thermostat.

Heads of cylinders

Heads of cylinders are made of an aluminum alloy by a molding method under pressure that provides high efficiency of the heat sink with an insignificant mass of a product.

The design of the gas-distributing DOHC mechanism located in a head corresponds to the scheme "four valves on the cylinder". The arrangement of inlet valves provides formation of the falling stream while final valves are connected with each other and form the uniform pass having the oval section through passage. The combination of a tent design of combustion chambers to the central arrangement of spark plugs and the organization of the falling stream in inlet ports promotes formation of area of an effective turbulence in combustion chambers of cylinders. Use of such scheme allows to achieve effective combustion of air and fuel mix and, as a result, increase of the power developed by the engine at the low content in the fulfilled gases of toxic components.

Cooling liquid circulates in the direction from forward part of a head of cylinders of each semi-block to back that increases efficiency of the heat sink.

Between a head of cylinders and the block of cylinders metal laying is used.

The drive of the right and left camshafts is carried out by different chains while auxiliary units are given by individual pulleys by means of the general streaming belt (in engines of the previous models two belts of the drive of auxiliary units were used).

The body of the camshaft having composite structure (for the first time in practice of Subaru) is formed of carbonaceous steel. The working ledges of cams made of a ceramic-metal alloy differ in the increased wear resistance allowing to increase considerably rise height at insignificant mass-dimensional characteristics of a product.

Each camshaft is established in four bearings. The neck of the forward bearing is equipped from both parties with the persistent flanges limiting the size of an axial side play of a shaft.

Greasing to bearings moves from the central maslotok through openings in veyka.

On the back end of the right inlet camshaft the flange which is used by the CMP sensor when determining an angle of rotation of a shaft is located.