Skoda Felicia

since 1994 release

Repair and operation of the car

Skoda Felicia
+ Cars of the Skoda Felicia brand
+ Maintenance instruction
+ Routine maintenance
- Repair of the engine
   - Repair without extraction from the car of the petrol engine of 1.3 l
      Description of the main knots and mechanisms
      Check of a condition of conrod and piston group on hearing and measurement of compression pressure in cylinders
      Reduction of the piston of the first cylinder in the provision of the top dead point (TDP)
      Removal and installation of a cover of a casing of the camshaft
      Removal, check of a state and installation of assembly of an axis of yokes
      Removal and installation of a head of cylinders assembled with the inlet pipeline and a final collector
      Removal, check of a state and installation of a forward cover, chain and asterisks of the GRM drive
      Removal, check of a state and installation of components of the oil pump
      Removal and installation of the pallet of a case of the engine
      Replacement of epiploons of a bent shaft
      Removal, check of a state and installation of a flywheel
      Check of a state and replacement of rubber pillows of support of a suspension bracket of the power unit
      Removal, installation and adjustment of effort of a tension of a belt of the drive of auxiliary units
   + Repair without extraction from the car of the petrol engine of 1.6 l
   + Repair without extraction from the car of the diesel engine
   + Dismantle of the power unit and capital repairs of the engine
+ Cooling systems, heating
+ Power supply system
+ Engine electric equipment
+ Coupling
+ Transmission
+ Power shafts
+ Brake system
+ Suspension bracket and steering
+ Body and finishing of salon
+ Onboard electric equipment

Description of the main knots and mechanisms

Head of cylinders (front view)

1 — the Candle opening
2 — the Tag of connection of a candle wire

3 — the Directing plugs of valves

Head of cylinders (rear view)

1 — Openings of final valves
2 — a tverstiya of inlet valves
3 — the Opening of an exit of cooling liquid

4 — Openings of inlet valves

Head of cylinders

Appearance of a head of cylinders is presented on an illustration.

In a head of cylinders combustion chambers are placed. In aluminum casting of a head the directing plugs of valves are pressed. Plugs are manufactured of cast iron with 0.5% addition of phosphorus.

In walls of combustion chambers of a head of cylinders saddles of inlet and final valves are pressed (a saddle of the inlet valve more on diameter).

Inlet and final channels are brought to the same party of a head that allows to provide a preliminary warming up of air-fuel mix in inlet canals. Inlet channels have the round section (Ø of 25 mm) and are removed above final, having the oval section of 22 x 30 mm.

From the opposite side of a head of cylinders carving openings under installation of spark plugs (M14x1.25) are provided. Near candle niches the tags in the form of figures from 1 to 4 specifying to what conclusion of a cover of the distributor of ignition are put VV a wire of this candle has to be connected.

Water galleries are connected to an exhaust outlet near which the case of the thermostat and with the inlet openings located in the top part of a head of cylinders near combustion chambers is installed.

The surface of a head interfaced to the block and the internal surfaces of combustion chambers are subjected to careful machining with the observance of requirements to a form and purity allowing to observe similarity of volumes of all combustion chambers and to achieve equal extent of compression in all cylinders. Besides, processing guarantees tightness of joints.

The head of cylinders fastens to the block ten bolts of M11 with six-sided heads and four nuts, navorachivayemy on M8 hairpins. Seven bolts have length of 168 mm, two - 183.5 mm and one - 132.5. In heads of bolts there is a six-sided deepening under a prutkovy key on 10 mm.

Laying of a head of cylinders is made of the material reinforced, not containing asbestos. Thanks to small elasticity of laying need for pulling up of bolts of fastening of a head after the first thousand kilometers of a run disappears.

From above the head is closed by a cover which is also cast from aluminum alloy. The cover of a head of cylinders is equipped with a maslozalivny mouth which is closed by a plastic stopper. Tightness of landing of a stopper is provided at the expense of the equipment with its rubber sealing ring of 70х60 mm.

Between a head of cylinders and its cover the rubber sealing laying preventing leak of motive oil is established.

Block of cylinders

The block of cylinders is the main bearing detail of a design of the power unit. The block is made of light aluminum alloy by a casting method under pressure. The mass of the block makes 13 kg.

In the lower part of the block of cylinders three bearings of radical necks of cranked are located. The bent shaft has three radical necks (a so-called not full-basic bent shaft).

Covers of radical bearings are made of cast iron and as are not interchangeable, marked designated by the corresponding figures. On the second cover from outer side there is an opening with a carving for fastening of a maslozabornik of the oil pump.

Covers of radical bearings fasten M11 bolts which required effort of tightening makes 67 ÷ 75 Nanometers).

Channels for cooling liquid, and also channels for an oil supply are provided in the block of cylinders.

The carving in openings in the block under bolts of fastening of a head of cylinders begins 30 mm below than the top cut of an opening thanks to what the best tightness of a joint of knots is provided and concentration of tension of casting around fixture decreases.

To the lower part of the block nine bolts of M6 the case pallet fastens.

Sleeves of cylinders

Sleeves are made of gray cast iron with addition of 0.5% of phosphorus. Sleeves are established in openings of cylinders in the block.

The external surface of sleeves is washed by cooling liquid, i.e. these are so-called "wet" sleeves.

Working surfaces of sleeves are exposed to a honingovaniye with high precision purity degree.

Each of sleeves is equipped with two adjusting corbels, one of which is located from above, and another - at distance about 2/3 lengths of a sleeve are closer to bottom edge of the last.

For a guarantee of correctness of installation of sleeves the manufacturer releases copper ring adjusting washers 0.10, 0.12 and 0.14 mm thick. A selection of adjusting washers try to obtain that the sleeve acted from the combustion chamber on strictly set height. Sleeves have to act over the surface of the block at 0:07 ÷ of 0.13 mm.

Sleeves are made with a nominal internal diameter of 75.5 mm and packed in groups on admissions of three classes: And, In and With (see Specifications). The class of a sleeve is put on its side surface.

The manufacturer does not provide a possibility of use of sleeves of the repair sizes.

Gas-distributing mechanism

Scheme of action of GRM

1 — a camshaft Cam
2 — the Pusher
3 — a pusher Bar
4 — the Valve
5 — the External spring

6 — the Internal spring
7 — the Plate
8 — a valve drive Yoke
9 — the Adjusting screw
10 — the Lock-nut

The gas-distributing mechanism (GRM) operates an admission in cylinders at the corresponding moments of fresh air-fuel mix and release from combustion chambers of the fulfilled gases.

The engine concerns to family of OHV units, i.e. has the top arrangement of valves. The camshaft, respectively is below. The scheme of operation of the mechanism is submitted on an accompanying illustration.

Camshaft cams, rotating lift pushers which movement is transmitted through bars to yokes. Yokes are put on the separate axis fixed by means of arms on a head of cylinders. Making oscillating motions, yokes directly influence cores of valves, forcing the last to open and be closed in the necessary timepoints.

Each of valves nestles on the saddle two springs (internal and external). Valves move in the directing plugs pressed in a head of cylinders.

The camshaft operating functioning of valves by means of eight eccentric cams is made of high-quality steel. Cams are tempered by current of high frequency. The camshaft is installed in three bearings of sliding pierced directly in casting of the block of cylinders. To facilitate installation of a shaft in bearings, all three from them have various diameter. The neck, the first from the GRM drive, has the largest diameter, average - is slightly less, and, at last, the last (the next to a flywheel), - the smallest. Camshafts only with necks of the nominal size are issued (see Specifications).

Each couple of cams operates opening and closing of valves of one cylinder. Rassovmeshcheniye of working ledges (rises) of cams defines the moments (corners relatively VMT) opening and closing of valves (see Specifications at the beginning of the present Chapter).

On a forward pin of a bent shaft the leading asterisk of a chain of the GRM drive is established. On distributive - conducted. Asterisks are put on pins of shaft внатяг, blocked from a provorachivaniye by segment splines and pressed by the bolts screwed in end faces of pins.

On distributive, except the conducted asterisk, also the gear wheel of the drive of the oil pump and distributor of ignition is established to a shaft. In view of told, the vital value gains correctness of mutual provision of asterisks as installation of phases of gas distribution depends on it.

Correctness of position of the camshaft in relation to cranked is reached by the corresponding placement of tags of both asterisks. Tags are executed in the form of superficial drillings and have to defend from each other on the distance equal to 12 links of a chain. At the same time, the link located over a tag of the leading asterisk is considered the first, over the tag conducted - the twelfth.

Pushers are executed in the form of the open cylinder One party of the bottom of a pusher interacting with a cam tore, is flat, with another spherical deepening which the pusher bar end face enters is provided. The working surface of a pusher is made very firm.

Bars of pushers transfer the movement to yokes of the drive of valves. Bars are made by forging of a steel bar with the tempered and polished ends. The top end of a bar has the bell form whereas lower is executed in the form of slightly expanded half-sphere. Bars of pushers of inlet and final valves have identical length.

Yokes serve for transfer of the movement from bars of pushers to cores of valves. The yoke surface adjoining to a core of the valve is forged. Yokes of inlet and final valves differ in a form, but are put on the general axis.

The shoulder of a yoke turned to a pusher bar is equipped with a carving opening in which the adjusting screw which rotation it is possible to regulate a thermal gap of the valve is rolled. The head of the adjusting screw is tempered, for blocking the flat lock-nut is provided.

In a middle part of a yoke are drilled the sensor switch small the channel. Via one channel supply of oil for lubricant of an axis of yokes is carried out, through the second oil is injected between rounds of valvate springs in the direction of a valve core.

Valves open and close inlet and final channels of combustion chambers that allows in the necessary timepoints to make filling of cylinders with fresh air-fuel mix and to take away from them the fulfilled gases.

Valves are made of special steel. The valve consists of a core and a plate. The conical part of a plate adjacent to a saddle of the valve and carrying the name of the condensing surface, is mown odes by a corner 45 ° 30' ± 5' (in valves of the Czech production), or 44 ° 50' ± 20' (in valves of import production).

The core of the valve is made of steel, a plate - of AKMV alloy, and the condensing surface of a plate is in addition covered with a layer of special Stelit F alloy which protects it from the destroying influence of the gases warmed to very high temperatures.

Inlet valves are made of heat-resistant steel, the condensing surface of a plate is formed by a forging method. Cores of valves are chromeplated that reduces a component of friction and prevents probability of jamming in the directing plugs.

The used materials, on condition of respect for frequency of adjustments of valvate gaps, guarantee serviceability of functioning of valves during 120 000 km of a run.

Diameter of a plate of the inlet valve makes 34 mm, final - 30 mm. It is made as much as possible to reduce the area contacting to the hot fulfilled gases. On the end of cores of valves flutes under installation of crackers of cutting locks are provided.

Cutting locks consist of the double conical plug - crackers which are fixed on a core by the top plate of springs. Springs press plates of valves the condensing surfaces to saddles, providing thereby due tightness of combustion chambers.

Springs are made of special steel. Each valve is equipped with two cylindrical springs: external and internal. Use of two springs instead of one is caused by the fact that owing to limitation of an empty seat, one spring will not be capable to provide due effort of pressing of a plate to a saddle. Springs are twisted in opposite directions thanks to what danger of an interlacing of their rounds in case of damage is eliminated.

Height of springs is picked up so that at the maximum compression (at the open valve) rounds did not adjoin among themselves.

The lower rounds of springs rest against a surface of a head of cylinders through a steel washer. Use of such washers was a compulsory measure as the head of cylinders is made of soft aluminum alloy.
25 Rest the Top end faces of a spring against the plate fixed on the end of a core of the valve. Nominal parameters of valvate springs are specified in Specifications.

The directing plugs of valves are made of cast iron. The problem of plugs consists in constantly to support the valve in the correct situation concerning a saddle, to provide its free movement and to take away excess of heat. Plugs are pressed in a head of cylinders. The release of plugs of the repair sizes is not made.

Maslootrazhatelny caps are put on plugs. From the inside of a cap the ring ledge collecting excess of oil from a valve core is provided. In the top part of a cap the small ring spring providing its constant clip to a core is established. Use of maslootrazhatelny caps allows to cut the consumption of motive oil connected with its penetration into combustion chambers. Respectively, issue level in the atmosphere of hydrocarbonic connections decreases.

Saddles of valves provide tightness of closing of valves and heat removal from the last. Saddles are made of special cast iron, rings of rectangular section have the form and under very high pressure are pressed in a body of a head of cylinders. The material applied to production of saddles allows to apply both unleaded, and ethylated gasolines to gas station of the car.