Technical characteristics of diesel engines (Scorpio 1)

Engine code (located on the cylinder block next to the dipstick)	STR, N-STR, SFA, SF, 4AB, 4BA, 4CA
Number of cylinders	4 in a row
Cylinder firing order	1–3–4–2
Cylinder diameter	94.00 mm
Piston stroke	90.0 mm
Working volume	2499 cm³
Compression ratio	23,0
Pressure when turning the engine with the starter	20 – 25
Power kW/hp:
- STR engine	51/69 at 4200 rpm.
- SFA engine	68/92 at 4150 rpm.
– SF engine	85/115 at 4200 rpm.
Maximum torque:
- STR engine	148 Nm at 2000 rpm.
- SFA engine	201 Nm at 2000 rpm.
– SF engine	270 Nm at 2200 rpm.

Cylinder head

The head is made of light alloy with inserted combustion chambers, valve seats and guides.

Cylinder head height	90±0.15 mm
Maximum reduction of head height during processing	0.5 mm
Maximum non-flatness of the lower plane of the cylinder head	0.15 mm
Lever axis diameter	18.96 – 19.00 mm

Cylinder head gasket

Cylinder head gaskets were made of synthetic material and initially had two thicknesses, and then three thicknesses. The thickness of the gasket is selected depending on the protrusion of the pistons above the upper plane of the engine cylinder block. The thickness of the gasket is identified by the number of cuts on its edge.

Piston protrusion	Gasket thickness
from 0.69 to 0.79 mm	1.53mm (designation: 2 notches)
from 0.79 to 0.89 mm	1.63mm (designation: 3 notches)
more than 0.89 mm	1.73mm (designation: 4 notches)

Only new type gaskets (three thicknesses) are manufactured as spare parts.

Combustion chambers

Swirl combustion chambers, steel, inserted into the cylinder head and fixed with a ball.

Combustion chamber type	vortex Ricardo Comet Mark V
Ball diameter	3 mm
Protrusion of swirl chambers from the lower plane of the cylinder head	0 – 0.03 mm

Valve seats

The valve seats are pressed into the cylinder head.

Valve seat working chamfer angle:
- intake	120°
- graduation	90°
Working chamfer width	2.2 – 2.5 mm

Valve guides

The valve guides are pressed into the cylinder head and are the same for both intake and exhaust valves.

O.D:
- nominal	14.048 – 14.059 mm
- first repair	14,280 – 14,290 mm
- second repair	14,579 – 14,590 mm
Inner diameter	8.520 – 8.542 mm
Length	55 mm
Distance between the guide and the lower plane of the cylinder head	27.95 – 28.05 mm

Valves

The valves are installed in the cylinder head vertically and parallel to each other (at right angles to the lower plane of the cylinder head).

Working chamfer angle:
- inlet valve	120°
- exhaust valve	90°
Operating valve clearance on a cold engine (four hours after the last start):
– naturally aspirated engine:
inlet valve	0.30 – 0.35 mm
exhaust valve	0.30 – 0.35 mm
– turbocharged engine:
inlet valve	0.10 – 0.20 mm
exhaust valve	0.20 – 0.30 mm
Valve lift:
- inlet valve	8.95 (Turbo 8.48) mm
- exhaust valve	8.22 (Turbo 8.27) mm
Distance from the lower plane of the cylinder head to the valve plate:
- inlet valve	0.75 – 1.25 mm
- exhaust valve	1.05 – 1.45 mm

Valve sizes

Inlet valve:
- length	116.25 mm
– valve plate diameter	42.5 mm
– rod diameter	8.473 – 8.495 mm
– thickness of the working edge of the valve plate	2.2 – 2.5 mm
Exhaust valve:
- length	116.25 mm
– valve plate diameter	35.5 mm
– rod diameter	8.453 – 8.475 mm
– thickness of the working edge of the valve plate	2.2 – 2.5 mm
Maximum allowable clearance between valve stem and guide bushing	0.15 mm

Valve springs

Length of spring in free state:
- external	44.6 mm
- internal	41.0 mm
Spring wire diameter:
- external	4.6 mm
- internal	2.4 mm

Engine cylinder block

The engine cylinder block is made of cast iron.

Number of main journals	5
Cylinder diameter:
- nominal class A	94,000 – 94,015 mm
– nominal class B	94.015 – 94.030 mm
- repair 1 class C	94.200 – 94.215 mm
- repair 1 class D	94.215 – 94.230 mm
- repair 2 class E	94.400 – 94.415 mm
- repair 2 class F	94.415 – 94.430 mm
- repair 3 class G	94.600 – 94.615 mm
- repair 3 class H	94.615 – 94.630 mm
- repair 4 class S	94.800 – 94.815 mm
- repair 4 class K	94.815 – 94.830 mm
Pusher Socket Diameter:
- nominal	24.00 – 24.03 mm
- repair	24.20 – 24.23 mm
Clearance between pusher and socket	0.04 – 0.08 mm

Crank mechanism

Crankshaft

Number of molar necks	5
Crankshaft axial play	0.08 – 0.29 mm
Fixation against axial movement	thrust half rings
Thickness of thrust half rings:
- nominal	2.30 – 2.33 mm
- repair	2.50 – 2.53 mm
Main bearing clearance	0.040 – 0.098 mm
Main journal diameter:
- standard	59.994 – 60.021 mm
- reduced by 0.30 mm	59.694 – 59.721 mm
- reduced by 0.50 mm	59.494 – 59.521 mm
- reduced by 0.80 mm	59.194 – 59.221 mm
Neck length:
- front	38.40 – 38.55 mm
- intermediate	30.4 – 30.6 mm
- central	37.76 – 37.81 mm
- back	37.84 – 38.04 mm
Gap in the necks	0.040 – 0.098 mm
Connecting rod journal diameter:
- nominal	54.994 – 55.021 mm
- repair (-0.3)	54.694 – 54.721 mm
Neck length	36.0 – 36.1 mm
Width of connecting rod bearing	29.0 mm
Maximum crankshaft turning force	60 Nm

Main bearings

These are thin-walled liners with a shell made of sheet steel and antifriction material made of zinc-aluminum alloy.

Width of inserts:
- front, middle and rear	29.80 mm
- intermediate	21.80 mm

Connecting rods

Connecting rod head bore:
- upper (under the bushing)	32,975 – 33,000 mm
- lower	58.737 – 58.750 mm
Connecting rod bushing:
– inner diameter	30.007 – 30.020 mm
– outer diameter	33,000 – 33,025 mm
Axial clearance on the crankshaft journal	0.10 – 0.25 mm
Clearance between the bearing and the crankpin	0.040 – 0.092 mm

Piston pins

The pin is made of steel and is surface-hardened. The pin rotates in the piston and connecting rod head bushing (the so-called floating pin) and is fixed from longitudinal movement by two spring retaining rings.

Finger diameter:
- STR engine	29,994 – 30,000 mm
- SFA engine	32,000 mm

Pistons

The pistons are made of aluminum-silicon alloy. The maximum difference in mass of a set of engine pistons should not exceed 5 g.

Installation method in the cylinder: the recesses on the bottom of the piston (for the valve plates and combustion chamber) should be on the fuel pump side.

Piston diameter (measurements are taken at a distance of 15.8 mm from the piston bottom perpendicular to the piston pin):
- nominal class A	93.855 – 93.900 mm
– nominal class B	93.900 – 93.915 mm
- repair 1 class C	94.085 – 94.100 mm
- repair 1 class D	94.100 – 94.115 mm
- repair 2 class E	94.285 – 94.300 mm
- repair 2 class F	94.300 – 94.315 mm
- repair 3 class G	94.485 – 94.500 mm
- repair 3 class H	94.500 – 94.515 mm
- repair 4 class S	94.685 – 94.700 mm
- repair 4 class K	94.700 – 94.715 mm
Piston protrusion from the engine cylinder block	0.50 – 0.92 mm (Turbo 0.40 – 0.87 mm)

Piston rings

Each piston is equipped with two sealing rings and one oil scraper ring, consisting of three parts.

Piston rings:
- upper seal	chrome plated, spherical
- compression	with notch (up)
- oil scraper	U-shaped

Piston ring gaps (installed in the cylinder):
- upper sealing ring	0.40 – 0.65 mm (Turbo 0.25 – 0.50 mm)
- compression ring	0.35 – 0.60 mm (Turbo 0.20 – 0.40 mm)
- oil scraper ring	0.15 – 0.30 mm (Turbo 0.15 – 0.45 mm)
Height of rings:
- upper seal	1,978 – 1,990 mm
- compression	1,978 – 1,990 mm
- oil scraper	4.478 – 4.490 mm

Gas distribution system

The valve timing system consists of a camshaft mounted in the cylinder block, tappets, tappet rods, valve levers and valves.

The camshaft is driven by a double-row chain from the crankshaft.

Valve timing:
– opening of intake valves	8° before TDC
– closing of intake valves	40° after BDC
– opening of intake valves	56° before BDC
– closing of intake valves	12° after TDC

TDC and BDC are the top and bottom dead centers, respectively.

Camshaft

The camshaft rotates in three bearings and is driven by a chain.

Camshaft journal diameters	41.925 – 41.950 mm
Working clearance of camshaft journals	0.05 – 0.11 mm
Axial play of the camshaft	0.05 – 0.15 mm

Lubrication system

Pressure lubrication is provided by a gear oil pump driven by the camshaft via an angular gear transmission. The lubrication system has a replaceable filter and an oil cooler.

Oil pump type	gear
Engine oil capacity:
- no filter	5.0 dm³
- with filter	5.6 dm³
Type of motor oil	API SE/ CD or SF/ CD
Viscosity of motor oil at temperature:
– from 20°C to +30°C	SAE 10W-30
– above -20°C	SAE 10W-40/ 10W-50
– above -15°C	SAE 15W-40/ 15W-50
– below -20°C	5W-30
Replacement frequency	every 7500 km or once every six months

Oil pressure sensor

The oil pressure sensor is located in the oil filter holder.

Indicator light ignition pressure

0.08 – 0.10 MPa

Cooling system

The closed cooling circuit with antifreeze liquid circulating under pressure contains a radiator, expansion tank and coolant pump. Air is removed from the system automatically after the engine is started.

Coolant pump

The centrifugal coolant pump, located on the front wall of the cylinder block, is driven by a V-belt. The coolant pump is not repairable and must be replaced if it fails.

Rotor diameter

60 mm

Thermostat

The wax thermostat is located in the same housing as the coolant pump.

Brand	Calorstat
Opening start temperature	72°C
Full opening temperature	81°C
Minimum valve stroke	7.5 mm

Coolant

Quantity	9.5 dm³
Type	special antifreeze liquid Ford SQM 97 B 9103A
Maintenance frequency	check the level every 7500 km (does not require periodic replacement of the coolant)

Fuel system

The fuel system contains a CAV Roto Diesel distribution fuel pump.

Fuel pump

The Roto Diesel rotary fuel pump is equipped with a hydraulic device for increasing the fuel dose during cold starting with automatic support for increased idle speed, controlled thermostatically, and an electromagnetic engine shut-off valve (STOP valve) that stops the fuel supply.

Brand and type	Roto Diesel or Lucas Roto Diesel
Injection order (cylinder #1 from flywheel side)	1–3–4–2
Start of injection	position of piston of 1st cylinder of engine 2.85 mm before TDC or 18° before TDC
Idle speed:
- without turbocharging	800 rpm.
- turbocharged	875 – 900 rpm.
Fast idle speed (cold engine)	880 – 930 rpm.
Maximum speed (no load)	4800 – 4850 rpm.
Time to reduce speed from maximum to idle	5 seconds
Turbocharger	Garret AiResearch T03

Nozzles

The injectors are screwed into the cylinder head.

Injector body	Roto Diesel or Bosch KSA 30 S 44
Injector opening pressure:
- without turbocharging	11.5±0.5 MPa
- turbocharged	13.0±0.5 MPa

Glow plugs

Brand and type	Bosch, Beru, Lucas or Champion CH68
Control temperature of glow plug heating (for 7 seconds at an ambient temperature of 20°C)	850°C

Tightening moments

Cylinder head mounting bolts:
– Stage 1	30 Nm
– Stage 2	70 Nm
– Stage 3 – unscrew the bolts in the tightening order by 90° and tighten again	70 Nm
– Stage 4 – after 10 minutes of engine operation at 3000 rpm and cooling for 4 hours, tighten twice (once*) (unscrew 90° and tighten)	70*/ 80 Nm
- Stage 5	turn 120°
Lever adjusting bolt locknuts	12.5 – 17.5 Nm
Cylinder head cover	3 – 4 Nm
Nuts for the inner struts of the lever axle	17 – 22 Nm
Tappet cover	5 – 7.5 Nm
Oil drain plug	7.5 – 12.5 Nm
Oil receiver	5 – 7.5 Nm
Oil level gauge tube	20 – 30 Nm
Main bearing caps	100 – 120 Nm
Connecting rod bearing caps	53 – 62 Nm
Flywheel:
– Stage 1	15 Nm
– Stage 2	95 Nm
Crankshaft pulley	240 – 260 Nm
Oil pump	25 – 30 Nm
Oil pump plugs	80 – 100 Nm
Oil pump cover	5 – 7.5 Nm
Engine Lift Bracket	10 – 12 Nm
Coolant drain plug on the cylinder block	20 – 30 Nm
Radiator Fan Clutch Fastening Nut	30 – 40 Nm
Fastening the alternator belt tensioner mechanism	21–25 Nm
Glow plugs	30 – 40 Nm
Gearbox to engine:
- type N	40 – 50 Nm
- type MT-75	70 – 90 Nm

*Applies to 70mm and 95mm bolt lengths only.

[The full article is on the online resource www.FordBook.ru]