Ford Sierra

1982-1993 of release

Repair and car operation

Ford Siyerra
+ 1.2. Car identification
+ 2. Maintenance
+ 3. General data
- 4. Engines
   - 4.1. Petrol engines
      + 4.1.1. Technical characteristics
      4.1.2. Adjustment of gaps of valves
      + 4.1.3. Ignition system
      - 4.1.4. Fuel system
         - The Ford carburetor with changeable section of a diffuzor
   Removal and carburetor installation
   Dismantling, check and carburetor assembly
   Adjustment of number of turns of idling of the engine and the contents WITH
   Adjustment of the starting arrangement
   Adjustment of a cable of a butterfly valve
   Removal and installation of a needle shaft
   Diaphragm of a vacuum regulator
         + Weber 32/36 DGAV carburetor
      + 4.1.5. The repair which is not demanding removal of the engine
      4.1.6. Removal and engine installation
      4.1.7. Engine dismantling
      4.1.8. Identification of cooperating parts
      4.1.9. Engine assembly
      4.1.10. Replacement of pistons
      4.1.11. Removal and installation of an intermediate shaft
      4.1.12. Gazoraspredeleniye system
      4.1.13. Greasing system
      + 4.1.14. Cooling system
      4.1.15. Suspension bracket of the power unit
      4.1.16. System of production of the fulfilled gases
   + 4.2. Diesel engine
+ 5. Coupling
+ 6. Transmissions
+ 7. Driveshaft and back bridge
+ 8. Steering
+ 9. Suspension brackets
+ 10. Brake system
+ 11. Body
+ 12. Electric equipment The Ford carburetor with changeable section of a diffuzor


The Ford carburetor with the closed butterfly valve in a cut

1–lever of a butterfly valve,
2–mobile zaslonka of a diffuzor,
4–main fuel jet,
5–additional fuel jet,
6–poplavkovy chamber,
7–screw of adjustment of structure of a mix,
8–the screw of an emphasis of a butterfly valve for adjustment of number of turns of idling

The Ford carburetor with an open butterfly valve in a cut

The Ford W carburetor (Motorcraft Venturi Variable) called also by the carburetor with changeable section of a diffuzor, single-chamber, with the poplavkovy chamber and the fuel spray of changeable section operated by vacuum.

The vacuum which is forming in an inlet collector thanks to operation of the engine, operates opening of a zaslonka of a diffuzor, and also change of section of the fuel jet closed by the calibrated conic needle. This carburetor has the device of enrichment of a mix during start of the cold engine, included automatically and operated by the bimetallic spring reacting to changes of temperature. The accelerating pump enriching a mix at fast opening of a butterfly valve, also copes vacuum.

The main system of a dosage of fuel consists of the main and additional jets, and also the calibrated conic needle regulating supply of fuel in a diffuzor of the carburetor. Fuel arrives from carburetor jets under the influence of the vacuum which is forming in a diffuzor through which passes air (between the main jet and a mobile zaslonka, see fig. The Ford carburetor with the closed butterfly valve in a cut and fig. The Ford carburetor with an open butterfly valve in a cut).

At small load of the engine the needle connected to a mobile zaslonka, almost completely closes the main fuel jet. In process of increase of load of the engine the vacuum and a mobile zaslonka gradually amplifies opens section of a diffuzor. Together with it the needle moves, increasing section of a stream of fuel, and also the additional fuel jet opens. The needle is made with big accuracy and makes an important element of an exact dosage of fuel depending on load of the engine. It is not necessary to regulate (to change installation) needles.

In a no-load time when to the engine a small amount of air arrives, the mobile zaslonka is in extreme, a closed position and is kept by a returnable spring of a diaphragm of a vacuum regulator. In process of opening of a diaphragm intensity of a proceeding stream of air grows and the vacuum in a diffuzor increases. This vacuum, influencing a regulator, causes moving of a zaslonka of a regulator, and together with it a mobile zaslonka and a needle. The provision of a diaphragm during every moment of time is defined by balance of forces influencing it: vacuum and returnable spring.