Ford Sierra

3.1.4.2.1.1. A head of the block of cylinders of the engine

THE GENERAL DATA

The head of the block of cylinders is made of an easy alloy. Has spherical chambers and the valve, inclined in two planes, forming V-shaped system and put in action cams of the cam-shaft located in a head of the block of cylinders, by means of hydraulic pushers and levers.

Key parametres

Admissible неплоскостность the bottom surface of a head of the block of cylinders	0,15 mm
The maximum depth of grinding of the bottom surface of a head of the block of cylinders	0,25 mm
The minimum depth of chambers of combustion after grinding of the bottom surface of a head of the block of cylinders	13,9 – 14,5 mm
Diameters of apertures of nests of plugs of bearings of a cam-shaft:
– The nominal	45,721 – 45,796 mm
– The repair	Are increased by 0,38 mm
Diameters of apertures of nests of pushers	22,25 ± 0,015 mm

Lining of a head of the block of cylinders

It is established by an inscription of "Torahs" upwards (towards a head of the block of cylinders).

THE VALVE

The valve are made of a special steel, are located V-shapedly and are put in action from a cam-shaft through hydraulic pushers and levers of valves.

The sizes of valves (mm)

Valve type	The inlet	The final
Length	136,50 – 136,96	133,66 – 134,12
Diameter of a plate	38,90 – 39,10	33,91 – 34,11
Diameter of a core:
– The nominal	8,025 – 8,043	7,999 – 8,017
– Repair 0,2	8,225 – 8,243	8,199 – 8,217
– Repair 0,4	8,425 – 8,443	8,399 – 8,417
Valve lifting	9,535	9,535
Core backlash in the directing	0,020 – 0,069	0,046 – 0,089

Working backlash of valves: zero, hydraulic pushers are used.

Saddles of valves

Saddles of valves are inserted into a head of the block of cylinders.

Corner of a working facet of the valve	45 °
Width of a working facet of the valve	1,75 – 2,32 mm
Corner of the top facet of a saddle:
– The inlet valve	30 °
– The final valve	20 °
Corner of the bottom facet of a saddle:
– The inlet valve	65 °
– The final valve	70 °

Directing valves

Directing valves are made of pig-iron and впрессованы in a head of the block of cylinders.

Diameters of apertures directing:

  – The nominal: 8,063 – 8,094 mm;
  – Repair 0,2: 8,263 – 8,294 mm;
  – Repair 0,4: 8,463 – 8,494 mm.

Springs of valves

The single springs identical both for inlet, and for final valves are used.

Free length: 45,4 – 47,2 mm.
Length at the open valve: 27 mm.
Length at the closed valve: 37,084 mm.

Levers of valves

The levers of valves shaped from a steel fasten the central bolt.

Pushers

Hydraulic pushers are made of a steel, stamped in a cold condition and have the cylindrical form.

External diameter:

  – The nominal: 22,25 mm;
  – Repair 0,25: 22,50 mm.