The Nissan A12 is a 1.2 l (1,171 cc, 71.45 cu-in) four-cylinder four-stroke gasoline engine from Nissan A-family. The engine was manufactured by Nissan Motor Company from 1970. In 1974 the A12 engine was redesigned.
The A12 motor uses a lightweight cast-iron block and an aluminum cylinder head, with overhead valves and a single camshaft. The engine was equipped with a two-barrel (twin-choke) Hitachi carburetor. Bore and stroke were 73.0 mm (2.87 in) and 70.0 mm (2.76 in), respectively. The compression ratio rating is 9.0:1. The A12 produced 71 PS (52.0 kW; 70.0 HP) of horsepower and 95 Nm (9.69 kg·m; 70.11 ft·lb) of torque.
For the 1974 model year, the A12 motor was modified, it used the new block style. The distributor was moved from the front side of the engine to the middle of the engine block to make room for an air conditioning system and anti-pollution air pump. Redesigned Nissan A12 engine used the new emission control technology, called NAPS (Nissan Anti Pollution System).
Special versions:
- The A12GX was equipped with twin Hitachi side-draft carburetors and longer-duration camshaft. The compression ratio was 10:1 and maximum power was 84 PS (62 KW; 83 HP) at 6,400 rpm. The A12GX was used on Sunny 1200 GX (Sedans and Coupes) for the JDM market.
- The A12T had identical specification with A12GX and was used on Nissan Cherry X-1.
- The AY12 was a racing version of the A12 engine with 1,300 cc (79 cu in) of displacement, a crossflow cylinder head, a special design of pistons and a valve rocker system.
The breakdown of the engine code is as follows:
- A – Engine Family
- 12 – 1.2 Liter Displacement
- S – Carburetor type
General information
| Engine Specifications | |
| Engine code | A12 |
| Layout | Four stroke, Inline-4 (Straight-4) |
| Fuel type | Gasoline (petrol) |
| Production | From 1971 |
| Displacement | 1.2 L, 1,171 cc (71.45 cu in) |
| Fuel system | Carburetor type |
| Power adder | None |
| Power output | 71 PS (52.0 KW; 70.0 HP) |
| Torque output | 95 Nm (9.69 kg·m; 70.11 ft·lb) |
| Firing order | 1-3-4-2 |
| Dimensions (L x W x H): | – |
| Weight | – |
Cylinder block
The A12 has a cast-iron cylinder block utilizes a five bearing supported system. The cylinder bore is 73.0 mm (2.87 in) and stroke is 70.0 mm (2.76 in). The A12 engine has two compression and single oil control ring.
| Cylinder block | ||
| Cylinder block alloy | Cast iron | |
| Compression ratio: | 9.0:1 | |
| Cylinder bore: | 73.0 mm (2.87 in)) | |
| Piston stroke: | 70.0 mm (2.76 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Number of main bearings: | 5 | |
| Cylinder inner diameter (standard): | 73.000-73.050 mm (2.8740-2.8760 in) | |
| Piston skirt diameter (standard): | 72.967-72.017 mm (2.8727-2.8747 in) | |
| Piston pin outer diameter: | 17.447-17.452 mm (0.6869-0.6871 in) | |
| Piston ring side clearance: | Top | 0.040-0.070 mm (0.0016-0.0028 in) |
| Second | 0.040-0.070 mm (0.0016-0.0028 in) | |
| Oil | 0.10 mm (0.0039 in) | |
| Piston ring end gap: | Top | 0.20-0.35 mm (0.0079-0.0138 in) |
| Second | 0.20-0.35 mm (0.0079-0.0138 in) | |
| Oil | 0.30-0.90 mm (0.0118-0.0354 in) | |
| Crankshaft journal diameter: | 49.943-49.964 mm (1.9663-1.9671 in) | |
| Crankpin diameter: | 44.954-44.974 mm (1.7698-1.7706 in) | |
| Connecting rod center distance: | 121.5 mm (4.78 in) | |
Cylinder head
The valve system has a push rod type rocker arm which uses the single type valve springs. The camshaft is driven with a double row roller chain from the crankshaft. The tension of the chain is controlled by the chain tensioner which is operated with spring and oil pressure. The rubber shoe type tensioner insulates vibration of the chain and controls the tension of the chain.
Intake valves are 35.0 mm (1.378 in) in diameter, and the exhaust valves are 29.0 mm (1.142 in).
| Cylinder head | ||
| Valve Arrangement: | OHV, chain drive | |
| Valves: | 8 (2 valves per cylinder) | |
| Valve timing: | INTAKE | 248° |
| EXHAUST | 248° | |
| Valve head diameter: | INTAKE | 35.0 mm (1.378 in) |
| EXHAUST | 29.0 mm (1.142 in) | |
| Valve length: | INTAKE | 102.35-102.65 mm (4.030-4.031 in) |
| EXHAUST | 102.35-102.65 mm (4.030-4.031 in) | |
| Valve stem diameter: | INTAKE | 7.960-7.975 mm (0.3134-0.3140 in) |
| EXHAUST | 7.945-7.960 mm (0.3128-0.3134 in) | |
| Valve spring free length: | 46.5 mm (1.831) | |
| Cam height: | INTAKE | 36.200-36.250 mm (1.4252-1.4272 in) |
| EXHAUST | 36.200-36.250 mm (1.4252-1.4272 in) | |
| Outer camshaft journal diameter: | №1 | 43.783-43.796 mm (1.7237-1.7242 in) |
| №2 | 42.283-43.296 mm (1.6647-1.7046 in) | |
| №3 | 42.783-42.796 mm (1.6844-1.6849 in) | |
| №4 | 42.283-42.296 mm (1.6647-1.6652 in) | |
| №5 | 41.208-41.221 mm (1.6224-1.6229 in) | |
Maintenance data
| Valve clearance (Cold) | |
| Intake valve | 0.25 mm (0.0098 in) |
| Exhaust valve | |
| Valve clearance (Hot) | |
| Intake valve | 0.35 mm (0.0138 in) |
| Exhaust valve | |
| Compression pressure | |
| Standard | 13.5 kg/m2 (192 psi) / 350 rpm |
| Minimun | 12.5 kg/m2 (178 psi) / 350 rpm |
| Oil system | |
| Oil consumption , L/1000 km (qt. per miles) | up to 0.5 (1 qt. per 1200 miles) |
| Recommended engine oil | 5W-30, 5W-40, 10W-30, 10W-40 |
| Engine oil capacity (Refill capacity) |
With oil filter 3.3 l (3.5 qt.) Without oil filter 2.8 l (3.0 qt.) |
| Oil change interval, km (miles) | 5,000-10,000 (3,000-6,000) |
| Ignition system | |
| Ignition coil | NGK: BP4ES; HITACHI: L47PW |
| Spark plug gap | 0.8 – 0.9 mm (0.031 – 0.035 in) |
Tightening torque specs
| Tightening torque specs | |
| Cylinder head bolt | 69-74 Nm; 7.0-7.5 kg·m; 51-54 ft·lb |
| Rocker shaft bracket bolt | 20-25 Nm; 2.0-2.5 kg·m; 14-18 ft·lb |
| Connecting rod big end nut | 32-38 Nm; 3.2-3.8 kg·m; 23-37 ft·lb |
| Flywheel bolt | 80-90 Nm; 8.0-9.0 kg·m; 58-65 ft·lb |
| Drive plate fixing bolt | 85-95 Nm; 8.5-9.5 kg·m; 61-69 ft·lb |
| Main bearing cap bolt | 50-60 Nm; 5.0-6.0 kg·m; 36-43 ft·lb |
| Camshaft sprocket bolt | 40-48 Nm; 4.0-4.8 kg·m; 29-35 ft·lb |
| Oil pan bolt | 15-20 Nm; 1.5-2.0 kg·m; 11-14 ft·lb |
| Oil strainer bolt | 9-14 Nm; 0.9-1.4 kg·m; 7-10 ft·lb |
| Oil pump bolt | 9-14 Nm; 0.9-1.4 kg·m; 7-10 ft·lb |
| Oil pan drain plug | 20-30 Nm; 2.0-3.0 kg·m; 14-22 ft·lb |
| Locating plate bolt | 4-5 Nm; 0.4-0.5 kg·m; 3-4 ft·lb |
| Carbutetor nuts | 5-7 Nm; 0.5-0.7 kg·m; 4-5 ft·lb |
| Manifold nuts | 15-20 Nm; 1.5-2.0 kg·m; 11-14 ft·lb |
| Fuel pump nuts | 9-14 Nm; 0.9-1.4 kg·m; 6.5-10 ft·lb |
| Crank pulley bolt | 150-200 Nm; 15-20 kg·m; 108-145 ft·lb |
| Engine mounting bolt | 19-25 Nm; 1.9-2.5 kg·m; 14-18 ft·lb |
| Water pump bolt | 9-14 Nm; 0.9-1.4 kg·m; 6.5-10 ft·lb |
| Rocker pivot lock nut | 16-22 Nm; 1.6-2.2 kg·m; 12-16 ft·lb |
| Timing chain cover bolt | 5-7 Nm; 0.5-0.7 kg·m; 4-5 ft·lb |
| Spark plug | 15-20 Nm; 1.5-2.0 kg·m; 11-14 ft·lb |
Vehicle applications
| Model | Years Produced |
| Nissan Sunny (B110, B120) | 1971–1973 |
| Nissan Cherry (E10) | 1971–1973 |
| Datsun 120A | 1971–1973 |
| Nissan 270X concept | 1970 |
| Premier 118NE (Fiat 124) | 1985-2001 |
| Nissan Sunny (B210) | 1974–1978 |
| Datsun 120Y | 1974–1978 |
| Nissan Cherry (E10) | 1974–1976 |
| Datsun 120A | 1974–1976 |
| Nissan Sunny (B310) | 1978-1982 |
| Datsun 120Y | 1978-1982 |
| Nissan Sunny Truck | 1974–1995 |
| Nissan Pulsar (N10) | 1978–1982 |
| Nissan Cherry (N10) | 1978–1982 |
| Datsun 120A | 1978–1982 |
| Nissan Vanette (C120) | 1978–1988 |
| Premier 118NE | – |
Author:
kindly send me an image for (piston rings gaps orientation) datsun 120y. I will be so grateful