The Nissan P40 is a 4.0 liter (3,956 cc, 241.40 cu-in) straight-six, four-stroke cycle, liquid-cooled gasoline engine manufactured by Nissan Diesel Motor Co., Ltd. from 1959.
The Nissan P40 engine has a cast-iron block, overhead valves, featuring bathtub-shaped combustion chambers, a fully balanced seven-bearing crankshaft, and a two-barrel carburetor.
The P40 engine in the Nissan Patrol 160 (MQ\MK) was different from the P40 that was used in the Nissan Patrol G60. The bore and stroke are the same so therefore the pistons and rods are the same. The cylinder heads are also the same, but the intake manifold is different.
Cylinder bore and piston stroke are 85.7 mm (3.37 in) and 114.3 mm (4.50 in), respectively. The compression ratio is 7.6:1. It produced form 116.0 PS (85.0 KW; 114.0 HP) at 3,400 rpm up to 145.5 PS (107.0 KW; 143.5 HP) at 3,400 rpm of horsepower and from 270.0 Nm (27.5 kg·m; 199.3 lbf·ft) at 2,000 rpm to 318.0 Nm (32.4 kg·m; 234.7 lbf·ft) at 2,000 rpm of torque.
The breakdown of the engine code is as follows:
- P – Engine Family
- 40 – 4.0 Liter Displacement
General information
| Engine Specifications | |
| Engine code | P / P40 |
| Layout | Four stroke, Inline-6 (Straight-6) |
| Fuel type | Gasoline |
| Production | – |
| Displacement | 4.0 L, 3,956 cc (241.40 cu-in) |
| Max. horsepower | 145.5 PS (107.0 KW; 143.5 HP) at 3,400 rpm |
| Torque output | 318.0 Nm (32.4 kg·m; 234.7 lbf·ft) at 2,000 rpm |
| Cooling system | Liquid-cooling |
| Fuel system | Carburetor |
| Power adder | None |
| Firing order | 1-5-3-6-2-4 |
| Dimensions (L x H x W): | 904 x 671 x 937 mm |
| Weight | 650 lbs (295 kg) |
Cylinder block
The P40 engine has a cast-iron cylinder block, bore is 85.7 mm (3.374 in) and stroke is 114.3 mm (4.500 in). The pistons are each fitted with two compression rings and a single oil ring. The crankshaft of the P40 engine is fully balanced and supported by seven main bearings.
| Cylinder block | ||
| Cylinder block alloy | Cast iron | |
| Compression ratio: | 7.6:1 | |
| Cylinder bore: | 85.7 mm (3.374 in) | |
| Piston stroke: | 114.3 mm (4.500 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Number of main bearings: | 7 | |
| Cylinder inner diameter (standard): | 85.690-85.740 mm (3.3736-3.3756 in) | |
| Piston skirt diameter (standard): | 85.650-85.699 mm (3.3720-3.3740 in) | |
| Piston pin outer diameter: | 20.648-20.653 mm (0.8129-0.8131 in) | |
| Piston ring side clearance: | Top | 0.031-0.078 mm (0.0012-0.0031 in) |
| Second | 0.031-0.078 mm (0.0012-0.0031 in) | |
| Oil | Combined | |
| Piston ring end gap: | Top | 0.25-0.40 mm (0.0098-0.0157 in) |
| Second | 0.15-0.30 mm (0.0059-0.0118 in) | |
| Oil | 0.20-0.90 mm (0.008-0.035 in) | |
| Connecting rod center distance: | 200 mm (7.87 in) | |
| Connectin rod small end inner diameter: | 20.618-20.630 mm (0.8117-0.8122 in) | |
| Crankshaft journal diameter: | 69.275-69.300 mm (2.7274-2.7283 in) | |
| Crankpin diameter: | 57.131-57.150 mm (2.2492-2.2500 in) | |
| Crankshaft center distance: | 57.150 mm (2.25 in) | |
Cylinder head
Intake valves are 43.0 mm in diameter, intake duration is 244°, and the exhaust valves are 36.2 mm, exhaust duration is 244°.
| Cylinder head | ||
| Valve Arrangement: | OHV, chain drive | |
| Valves: | 12 (2 valves per cylinder) | |
| Intake/Exhaust duration: | 244° / 244° | |
| Valve head diameter: | INTAKE | 43.0 mm (1.693 in) |
| EXHAUST | 36.2 mm (1.425 in) | |
| Valve length: | INTAKE | 130.05-130.35 mm (5.1201-5.1319 in) |
| EXHAUST | 131.35-131.65 mm (5.1712-5.1831 in) | |
| Valve stem diameter: | INTAKE | 8.637-8.650 mm (0.3400-0.3406 in) |
| EXHAUST | 8.627-8.640 mm (0.3396-0.3402 in) | Cam height: | INTAKE | 41.246 mm (1.6239 in) |
| EXHAUST | 41.246 mm (1.6239 in) | |
| Outer camshaft journal diameter: | №1 | 49.124-49.149 mm (1.9340-1.9350 in) |
| №2 | 48.920-48.925 mm (1.9260-1.9270 in) | |
| №3 | 48.161-48.641 mm (1.9140-1.9150 in) | |
| №4 | 48.311-48.336 mm (1.9020-1.9030 in) | |
| Rocker shaft outer daimetr | 19.975-20.000 mm (0.7864-0.7874 in) | |
| Rocker arm bushing bore daimetr | 20.020-20.033 mm (0.7882-0.7887 in) | |
Maintenance data
| Valve clearance (HOT) | |
| Intake valve | 0.38 mm (0.015 in) |
| Exhaust valve | 0.38 mm (0.015 in) |
| Compression pressure | |
| Standard | 11.5 kg/cm2 (11.28 bar, 164 psi) / 250 rpm |
| Minimun | 10.5 kg/cm2 (10.30 bar, 149 psi) / 250 rpm |
| Compression differential limit between cylinders | 1 kg/cm2 (0.98 bar, 14 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 |
| Oil type API | SE |
| Engine oil capacity (Refill capacity) | With filter change 5.7 liters (6.0 US.qts, 5.0 Imp. qts) Without filter change 5.1 liters (5.4 US.qts, 4.5 Imp. qts) |
| Oil change interval, km (miles) | 5,000-10,000 (3,000-6,000) |
| Ignition system | |
| Ignition timing (B.T.D.C./rpm) | 10°/550 rpm – Except Europe and Hong Kong 5°/650 rpm – For Europe and Hong Kong 10°/500 rpm – For Australia |
| Spark plug | Cold: BP7ES, L44PW, BPR7ES (NGK) Standard: BP6ES, L45PW, BPR6ES (NGK) Hot: BP5ES, BP4ES, L46PW, L47PW, BPR5ES, BPR4ES (NGK) |
| Spark plug gap | 0.8-0.9 mm (0.03 -0.035 in) |
| Distributor | |
| Point gap | 0.45-0.55 mm (0.018-0.022 in) |
| Dwell angle | 35°-40° |
Tightening torque specs
| Tightening torque specs | |
| Main bearing cap bolt | 98-118 Nm; 10-12 kg·m; 72-87 ft·lb |
| Connecting rod big end nut | 44-59 Nm; 4.5-6.0 kg·m; 33-43 ft·lb |
| Water pump bolt (M10) | 20-25 Nm; 2.0-2.5 kg·m; 14-18 ft·lb |
| Flywheel bolt | 78-98 Nm; 8.0-10.0 kg·m; 58-72 ft·lb |
| Front cover bolt | M8: 11-21 Nm; 1.1-2.1 kg·m; 8-15 ft·lb M10: 30-40 Nm; 3.1-4.1 kg·m; 22-30 ft·lb |
| Front plate bolt | 30-40 Nm; 3.1-4.1 kg·m; 22-30 ft·lb |
| Fliwheel housing bolt | 51-72 Nm; 5.3-7.4 kg·m; 39-54 ft·lb |
| Cylinder head bolt | 68-88 Nm; 7.0-9.0 kg·m; 51-65 ft·lb |
| Rocker shaft bracket bolt | 34-48 Nm; 3.5-4.9 kg·m; 25-35 ft·lb |
| Valve rocker adjusting screw | 30-38 Nm; 3.0-3.8 kg·m; 22-28 ft·lb |
| Camshaft sprocket bolt | 30-40 Nm; 3.1-4.1 kg·m; 22-30 ft·lb |
| Camshaft locating plate bolt | 6-8 Nm; 0.6-0.8 kg·m; 4.3-5.8 ft·lb |
| Oil pump bolt | 25-34 Nm; 2.5-3.5 kg·m; 18-25 ft·lb |
| Water pump nut and bolt | 25-34 Nm; 2.5-3.5 kg·m; 18-25 ft·lb |
| Crank pulley nut | 149-163 Nm; 15.2-16.3 kg·m; 110-120 ft·lb |
| Rocker cover bolt | 18-27 Nm; 1.8-2.8 kg·m; 13-20 ft·lb |
| Spark plug | 18-24 Nm; 1.8-2.4 kg·m; 13-17 ft·lb |
| Manifold bolt and nut | 25-34 Nm; 2.5-3.5 kg·m; 18-25 ft·lb |
| Water outlet bolt | 10-12 Nm; 1.0-1.2 kg·m; 7-9 ft·lb |
| Thermostat housing | 10-12 Nm; 1.0-1.2 kg·m; 7-9 ft·lb |
| Distributor support bolt | 10-12 Nm; 1.0-1.2 kg·m; 7-9 ft·lb |
| Alternator bracket | 22-29 Nm; 2.2-3.0 kg·m; 16-22 ft·lb |
| Engine mouting bracket | 37-50 Nm; 3.7-5.0 kg·m; 27-37 ft·lb |
| Carburetor nut | 14-18 Nm; 1.4-1.8 kg·m; 10-13 ft·lb |
| Fuel pump nut | 11-21 Nm; 1.1-2.1 kg·m; 8-15 ft·lb |
Vehicle applications
| Model | Years Produced |
| Nissan Patrol 4W66 | 1959-1960 |
| Nissan Carrier 4W73 | 1959- |
| Nissan 680 Truck | 1959-1968 |
| Nissan 690 Bus | 1960-1968 |
| Nissan Patrol 60 | 1960-1980 |
| Nissan FR40 | 1963-1968 |
| Nissan 681 Truck | 1968-1969 |
| Nissan 691 Bus | 1968-1969 |
| Nissan G780 | 1969- |
| Nissan Patrol 160 | 1980-1989 |
| Nissan Patrol 260 | 1986-2003 |
| Nissan Cabstar E690 | – |
Author: Sergei Wers About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.
