DOHC Engine Specifications (Sierra)

Engine	2.0 HC DOHC 2 V	2.0 HC DOHC EFI
Engine type	N8A	N9A
Cylinder diameter (mm)	86	86
Piston stroke (mm)	86	86
Working volume (cm³)	1998	1998
Compression ratio	10,3	10,3
Compression pressure (MPa)	1,1 – 1,3	1,1 – 1,3
Nominal power:
– in kW at rpm	80 at 5600	92 at 5600
– in hp at rpm	109 at 5600	125 at 5600
Maximum torque (Nm)	168	174
Number of revolutions at maximum torque (rpm)	3000	2500

Engine cylinder head

The cylinder head is die-cast from light alloy and has insert valve seats.

Designation: 20.

Camshaft bearing bushing hole diameters: 26.00–26.03 mm.

Caution! Grinding the lower surface of the cylinder head is not permitted.

Cylinder head gasket

The cylinder head gasket is installed without the use of sealant.

Brand: Reinz.

Valves

The valves are arranged in a V-shape, inclined at an angle of 20° to the cylinder axis and are actuated by two camshafts (intake valves and exhaust valves).

Valve dimensions (mm)

Valve type	Inlet	Outlet
Length	108,24 – 108,70	108,71 – 109,17
Plate diameter	42,5 – 42,7	37,9 – 38,1
Rod diameter:
- nominal	7,025 – 7,043	6,999 – 7,017
- repair 0.2	7,225 – 7,243	7,199 – 7,217
- repair 0.4	7,425 – 7,443	7,399 – 7,417
- repair 0.6	7,625 – 7,643	7,599 – 7,617
- repair 0.8	7,825 – 7,843	7,799 – 7,817
Clearance of the rod in the guide (mm)	0,020 – 0,069	0,046 – 0,095
Working chamfer angle	90°	90°

Valve clearance

The engine uses hydraulic tappets to provide automatic valve clearance adjustment.

Valve seats

Valve seats made from a steel-copper alloy are inserted into the cylinder head.

Valve seat dimensions

Saddle type	Inlet valve seat	Exhaust valve socket
Top chamfer angle	60°	60°
Working chamfer angle	89° – 90°	89° – 90°
Working chamfer width	1,33 – 2,19	1,68 – 2,54
Bottom chamfer angle	140°	140°

Valve guides

The valve guides are made of cast iron, inserted into the cylinder head and inclined to the cylinder axis at an angle of 120°.

Guide hole diameters (standard): 7.063 – 7.094 mm.

Valve springs

Two springs are used for each valve.

Valve spring characteristics

Spring type	External	Internal
Free length (mm)	46,8	46,2
Inner diameter (mm)	24	17,5
Wire diameter (mm)	4,5	2,5
Number of working turns	6,1	8

Engine cylinder block

The cylinder block is cast from cast iron, has cylinders made directly in the cylinder block and five main crankshaft bearings.

Designation (made in casting)	20
Nominal cylinder diameters
Standard:
- group 1	86,000 – 86,010 mm
- group 2	86.010 – 86.020 mm
Increased +0.15:
- Group A	86.150 – 86.100 mm
- Group B	86.160 – 86.170 mm
Increased +0.5	86,500 – 86,510 mm
Width of the middle main bearing shell seat	21.17 – 21.23 mm
Main bearing seat diameters:
- nominal	59.287 – 59.300 mm
- increased +0.4	59,687 – 59,700 mm

Crank mechanism

Crankshaft

The crankshaft is forged together with the counterweights and rests on five main bearings.

The axial clearance is adjusted by the thickness of the thrust half rings in the middle main bearing.

Main journal diameters
Nominal:
- the sign is yellow	54,980 – 54,990 mm
- the sign is red	54,990 – 55,000 mm
Reduced (green sign)	54,730 – 54,750 mm
Radial clearance in main bearings	0.011 – 0.048 mm
Crankshaft axial clearance	0.090 – 0.300 mm
Thickness of thrust half rings:
- nominal	2.301 – 2.351 mm
- repair (yellow sign)	2.491 – 2.541 mm
Connecting rod journal diameter:
- nominal	50.890 – 50.910 mm
- reduced (green sign)	50.640 – 50.660 mm

Main bearings

The half-liners located in the cylinder block have a hole and a groove for oil.

Inner diameter of liners after installation in the cylinder block:
- nominal	55.001 – 55.038 mm
- repair -0.05	54.951 – 54.988 mm
- repair -0.25	54.751 – 54.788 mm
- repair -0.50	54.501 – 54.538 mm
- repair -0.75	54.251 – 54.288 mm

Connecting rods

The connecting rods are forged from steel and have an I-section of the rod and a straight parting line of the lower head. The hole in the lower head of the connecting rod serves to spray oil into the piston for its cooling and lubrication, as well as for cooling the piston pin and the connecting rod head. Depending on the mass, the connecting rods are divided into four groups (A, B, C, D). The connecting rods in the engine must belong to the same group.

Bottom head hole diameter	53.890 – 53.910 mm
Head hole diameter	20.589 – 20.609 mm
Radial clearance in connecting rod bearings	0.006 – 0.060 mm

Connecting rod bearings

Inner diameter of the bearings after installation in the connecting rod:
- nominal	50.916 – 50.950 mm
- repair -0.025	50.891 – 50.925 mm
- repair -0.25	50.666 – 50.700 mm
- repair -0.50	50.416 – 50.450 mm
- repair -0.75	50.166 – 50.200 mm
- repair -1.00	49.916 – 49.950 mm
Connecting rod axial clearance (on crankshaft)	0.090 – 0.310 mm

Pistons

The pistons are cast from a light alloy, have a full jacket and an offset axis of the piston pin hole.

Installation method: The arrow on the bottom should point towards the timing drive.

Nominal piston diameters:
- group 1	85.970 – 85.980 mm
- group 2	85,980 – 85,990 mm
Piston repair diameters:
- standard	85,980 – 86,000 mm
- repair +0.15	86.130 – 86.150 mm
- repair +0.50	86.470 – 86.490 mm
Piston clearance in cylinder:
- nominal	0.020 – 0.040 mm
- repair	0.010 – 0.040 mm

Piston rings

Each piston has three rings:

• the first (upper) one is a barrel-shaped sealing one;
• second (middle) – sealing conical;
• the third (lower) one is an oil scraper (made of three parts with a spring expander).

Ring lock clearance (located in the cylinder):
- first seal	0.30 – 0.60 mm
- second seal	0.50 – 0.80 mm
- oil scraper	0.40 – 1.50 mm

Piston pins

The pins, made of steel, are pressed into the connecting rod head and rotate in the piston hubs.

Installation method: after heating the connecting rod to a temperature of 260°–300°C.

Length:	63.4 mm
Diameter:
- marked in white	20.622 – 20.625 mm
- marked in red	20.626 – 20.628 mm
- marked in blue	20.628 – 20.631 mm
- marked in yellow	20.631 – 20.634 mm
Piston hub clearance	0.008 – 0.014 mm
Connecting rod head tension	0.018 – 0.039 mm

Flywheel

The flywheel is bolted to the crankshaft with six asymmetrically located bolts.

Gas distribution system

The two camshafts are located in the cylinder head and are driven by a separate roller chain from the crankshaft and operate the valves via hydraulic tappets.

Camshafts

The two camshafts in the cylinder head are supported by five bearings: one operates the intake valves, and the other the exhaust valves.

Neck diameter	25,960 – 5,980 mm
Axial clearance	0.02 – 0.26 mm
Cam lift:
- intake valves in a carburetor engine	10.5 mm
- intake valves in a petrol injection engine	11.1 mm
- exhaust valves	10.9 mm

Valve timing

Engine type	N8A	N9A
OZD	13° before TDC	13° before TDC
ZZD	39° after BDC	51° after BDC
OZW	43° before BDC	43° before BDC
ZZW	13° after TDC	13° after TDC
OZD and ZZD – opening and closing of the intake valve, respectively
OZW and ZZW – opening and closing of the exhaust valve, respectively

Timing chain

Single row roller chain 3/8" with hydraulic tensioning.

Lubrication system

The pressure lubrication system contains an oil pump driven by a chain from the crankshaft, an oil filter with a replaceable element and an oil bypass valve.

Oil pump

The gear oil pump is located at the front of the engine cylinder block.

Oil pressure (at 80°C):
– at 750 rpm	0.16 MPa
- at 2000 rpm	0.31 – 0.46 MPa
Bypass valve opening pressure	0.37 – 0.46 MPa
Clearance of external gear in pump housing	0.154 – 0.304 mm
Clearance between outer and inner gears	0.05 – 0.20 mm

Oil filter

The replaceable oil filter contains a side channel that opens automatically in case of excessive contamination of the filter element.

Make and type: Motorcraft EFL 90.

Replacement frequency: after 10,000 km of vehicle mileage or after six months of vehicle use, then every 20,000 km or once a year.

Engine oil

Quantity (with filter): 4.75 dm³.

Type: all-season engine oil in accordance with API SG/CD with viscosity SAE 10W 30, 10W 40 or 10W 50.



Replacement frequency: after 10,000 km of vehicle mileage or after six months of vehicle use, then every 20,000 km or once a year.

Cooling system

Thermostat

The wax thermostat is located at the front of the engine near the intake manifold.

Temperature at the beginning of opening: 85°–89°C.

Full opening temperature: 102°±3°C.

Fan

The fan is driven by an electric motor, which is activated by a thermal switch located in the radiator drain plug.

The cooling system of cars equipped with a manual transmission contains one fan, and cars equipped with an automatic transmission contain two fans.

Expansion tank

The expansion tank is made of artificial material.

Opening pressure of the excess pressure valve in the expansion tank cap: 120 – 140 kPa.

Coolant

Quantity:

• engine 2.0 НС DOНС 2V (N8A): 7.9 dm³;
• engine 2.0 НС DOНС EFI (N9A): 7.3 dm³.

Type: mixture of special antifreeze liquid Ford Super Plus SSM 97 B 9103 A and distilled water (50% each).

Replacement frequency: once every two years.

Fuel system

The fuel system of the 2.0 НС DOHC 2V (N8A) engine uses an electric fuel pump and a Weber TLD carburetor, and the 2.0 НС DOHC EFI (N9A) engine uses a Ford Motorcraft EFI injection system combined with the ignition system and is part of the EEC IV engine management system.

Fuel tank

The fuel tank, made of sheet steel, is secured with two steel clamps in front of the rear axle.

Capacity: 60 dm³.

Fuel type: leaded petrol with an octane rating of 98 or unleaded petrol with an octane rating of at least 95 (engines adapted to run on unleaded petrol).

Air filter

The air filter has a replaceable paper element.

Make and type: Motorcraft EFA 56.

Fuel filter

Make and type: Motorcraft EFG 21.

Fuel pump

Carburetor engine

Electric fuel pump.

Fuel injection engine

Ford Electric Roller Slide Fuel Pump.

Generated pressure (at 12 V and closed fuel outlet): 300 kPa.

Weber carburetor

The Weber TLD two-chamber sequential carburetor has a 2nd chamber throttle valve controlled by intake manifold vacuum, an accelerator pump, an enrichment device in the 2nd chamber and an automatically actuated starting choke.

Weber TLD Carburetor Adjustment Data

Parameter	1st chamber	2nd chamber
Diffuser diameter (mm)	23	25
Main fuel jet	115	157
Emulsion tube	F114	F13
Main air jet	175	145
Installing the float	29±0,5	29±0,5
Opening the throttle valve	5±0,5	5±0,5
Turnovers "accelerated" idle speed (rpm)	1800±50	1800±50
Idle speed (rpm)	850±25*	850±25*
CO content (%)	1±0,25	1±0,25

*Cars with automatic transmission: 800±50 rpm.

Ford Motorcraft EFI Injection System

Multi-point fuel injection, controlled electronically, Ford Motorcraft EFI, is used, combined with the ignition system, which is part of the EEC IV engine management system. Fuel is supplied to the injectors with constant pressure. The EEC IV electronic control device doses the portion of the sprayed fuel and controls the ignition, and also shuts off the fuel supply to the engine during engine braking.

Fuel pressure regulator

Brand: Bosch.

Adjustable pressure: 230-250 kPa.

Fuel injectors

The fuel injectors are electronically controlled.



Brand: Bosch.

Adjustment data

Idle speed: 875±25 rpm.

CO content: 1.25±0.25%.

Ignition system

The 2.0 HC DOHC 2V (N8A) engine uses a battery-operated, microprocessor-controlled ignition system of the ESC II type, and the 2.0 HC DOHC EFI (N9A) engine uses a battery-operated, microprocessor-controlled ignition system of the ESC IV type, combined with the Ford Motorcraft EFI injection system.

The operating principle of both types of ignition systems is identical, but the system integrated with the injection system is more powerful.

The ignition system includes:

• ignition coil;
• ignition distributor containing a speed sensor and a high voltage distributor;
• electronic ignition control module or electronic device that controls injection and ignition;
• four spark plugs.

In addition (depending on the type) the ignition system contains:

• coolant temperature sensor (ESC II and EEC IV);
• vacuum sensor (ESC II);
• automatic transmission gear shift lever neutral position sensor (ESC II and EEC IV);
• throttle position sensor (EEC IV);
• absolute pressure sensor (EEC IV).

Ignition coil

Brand and type: Bosch 0 221 122 450.

Primary winding resistance: 0.72 – 0.88 Ohm.

Secondary winding resistance: 4.5 – 7 kOhm.

Distributor

The ignition distributor contains a contactless Hall sensor, which also acts as a speed sensor, and a high-voltage distributor. It is located at the front end of the intake camshaft.

Brand: Motorcraft.

Firing order (cylinder N1 from the valve timing drive side): 1–3–4–2.

Direction of rotation: clockwise.

N8A Engine Electronic Module

Brand: Motorcraft.

Type: Ford ESC II.

Electronic Engine Control Module N9A

Brand: Motorcraft.

Type:

• cars with manual transmission: Ford EEC IV 88 BB 12A 650 AB;
• cars with automatic transmission: Ford EEC IV 88 GB 12A 650 RB.

Spark plugs

Brand and type:

• engine 2.0 НС DOНС 2V (N8A): Motorcraft AGPR 32 CD;
• engine 2.0 НС DOНС EFI (N9A): Motorcraft Super AGPR 22 CD.

The gap between the electrodes is 0.75 mm.

Tightening moments

Cylinder head bolts:
– 1st stage (bolts M11 – sequence 1 – 10)	25 Nm
– 2nd stage (bolts M11 – sequence 1 – 10)	55 Nm
– 3rd stage (bolts M11 – sequence 1 – 10)	tighten 90°
– 4th stage (bolts M11 – sequence 1 – 10)	tighten 90°
– 5th stage (bolts M8 – sequence 1 – 13)	24 – 27 Nm
Cylinder head cover	6 – 8 Nm
Timing system housing	65 – 95 Nm
Guide chains of the valve timing system drive:
- top	10 – 13 Nm
- lower	24 – 28 Nm
Camshaft sprockets	55 – 63 Nm
Camshaft Bearing Caps	22 – 26 Nm
Main bearing caps	90 – 104 Nm
Connecting rod caps	26 – 34 Nm
- Stage 1	6 – 8 Nm
- 2nd stage	15 – 17 Nm
- Stage 3	tighten to 85° – 95°
Crankshaft torsional vibration damper	110 – 130 Nm
- Stage 1	45 – 58 Nm
- 2nd stage	tighten 80° – 90°
Oil pump to cylinder block	8.5 – 11.5 Nm
Oil pump pulley	16 – 19 Nm
Oil pump cardan chain tensioner	10 – 13 Nm
Coolant pump	21 – 28 Nm
Coolant pump pulley	21 – 28 Nm
Thermostat housing	9 – 12 Nm