Nissan TD42 Specifications
| Engine Model: Nissan TD42 |
| Engine Type: 4-cycle inline 6-cylinder OHV 12-valve liquid-cooled diesel |
| Total Displacement: 254.4 cu.in (4.17 L) |
| Rated Engine Power: 114-133 Hp (85-99 kW) at 4000 rpm |
| Fuel System Type: Indirect injection |
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The Nissan TD42 is a 4.2-liter, inline-six, naturally
aspirated diesel engine that stands as one of the most revered powerplants in
Nissan’s commercial and off-road vehicle history. Produced from the late 1980s
through the mid-2000s, the TD42 earned a legendary reputation for durability,
mechanical simplicity, and exceptional longevity, often exceeding 500,000
kilometers (310,000 miles) without major overhaul. Its robust construction and
gear-driven valvetrain eliminated the common failure points associated with
timing belts and chains, establishing the engine as the preferred choice for
applications demanding sustained high-load operation in remote and demanding
environments.
The TD42 is characterized by its all-cast iron construction - cylinder block,
cylinder head, and sump - a configuration chosen for maximum durability under
the high cylinder pressures of diesel operation. The engine employs an overhead
valve (OHV) valvetrain with two valves per cylinder, actuated by pushrods from a
camshaft located within the cylinder block.
The fuel system utilizes indirect injection (IDI) with swirl chambers and a
mechanical Bosch-type distribution injection pump. While the naturally aspirated
configuration produces modest power by modern standards, the engine’s square
bore and stroke ratio of 96.0 mm by 96.0 mm provides a favorable foundation for
the aftermarket turbocharging conversions that have made the TD42 a favorite
among off-road enthusiasts worldwide.
The TD42 is a four-stroke, water-cooled, naturally aspirated diesel engine
configured for longitudinal mounting in rear-wheel-drive and four-wheel-drive
vehicle architectures. Its inline-six configuration provides inherent primary
and secondary balance, contributing to smooth operation.
Engine Type: Inline-6, 4-cycle, water-cooled, naturally aspirated diesel.
Displacement: 4,169 cc (254.4 cu.in).
Bore and Stroke: 96.0 mm (3.78 in) x 96.0 mm (3.78 in).
Compression Ratio: 22.7:1.
Valvetrain: OHV, 12-valve (2 valves per cylinder) with pushrods and rocker arms.
Fuel System: Mechanical indirect injection (IDI) with swirl chambers.
Aspiration: Naturally aspirated.
Firing Order: 1-5-3-6-2-4.
Rated Speed: 4,000 rpm.
Redline: 4,500 rpm.
Early Variants (Pre-1992)
Maximum Power: 85 kW (114 hp) at 4,000 rpm.
Maximum Torque: 264 Nm (195 lb-ft) at 2,000 rpm.
Late Variants (1992-2007)
Maximum Power: 99 kW (133 hp) at 4,000 rpm.
Maximum Torque: 272 Nm (201 lb-ft) at 2,000 rpm.
The cylinder block is manufactured from high-strength
gray cast iron using a deep-skirt design, where the cylinder walls extend below
the crankshaft centerline to provide maximum structural rigidity under the high
cylinder pressures of diesel operation. The block features a closed-deck
configuration, ensuring the cylinder bores are fully supported by the water
jacket structure at the top deck surface for superior head gasket sealing.
Pressed-in, replaceable cast iron wet liners are employed, allowing for engine
rebuilding through liner replacement - a critical feature for a powerplant
intended for high-mileage service lives.
The block incorporates seven main bearing webs with two-bolt main bearing caps,
each machined in situ with the block for precise alignment. The timing gear
housing is cast integrally with the front of the block, providing a rigid
mounting point for the gear train. A large-capacity cast aluminum or stamped
steel oil pan is bolted to the lower crankcase, with capacity varying by
application to accommodate the deep-skirt block design.
Block Material: Cast iron.
Liner Type: Replaceable, pressed-in wet liners.
Bore Diameter: 96.0 mm (3.78 in).
Main Bearing Caps: Cast iron, two-bolt design with seven main bearings.
The cylinder head is constructed from cast iron,
matching the thermal expansion characteristics of the block to ensure reliable
head gasket sealing across the wide temperature range of diesel operation. The
head utilizes a cross-flow design with the intake manifold on the left side and
the exhaust manifold on the right side. The combustion system employs indirect
injection (IDI) with individual swirl chambers - pre-combustion chambers - for
each cylinder, formed by steel inserts pressed into the cylinder head. These
chambers provide a highly turbulent environment for fuel-air mixing before
combustion propagates into the main cylinder, enabling smoother, quieter diesel
operation.
The OHV valvetrain operates twelve valves - two per cylinder - via pushrods and
forged steel rocker arms. The camshaft is located within the cylinder block and
is driven by a gear train from the crankshaft. Valve clearance is set manually
using adjustment screws on the rocker arms, a system requiring periodic
maintenance. The valves are seated on hardened steel inserts pressed into the
cylinder head, with valve seat angles ground to 45 degrees.
Head Material: Cast iron.
Combustion Chamber Type: Indirect injection with steel swirl chamber inserts.
Valve Configuration: OHV, 2 valves per cylinder with pushrods and rocker arms.
Valve Diameter (Intake): 41.0 mm (1.61 in).
Valve Diameter (Exhaust): 35.0 mm (1.38 in).
Valve Stem Diameter: 9.0 mm (0.35 in).
Valve Seat Angle: 45 degrees.
Glow Plug Type: Sheathed type, pencil-style heating element.
Valve Clearance (Cold, Intake): 0.25-0.35 mm (0.010-0.014 in).
Valve Clearance (Cold, Exhaust): 0.35-0.45 mm (0.014-0.018 in).
The TD42 employs a mechanical indirect injection fuel
system. A Bosch VE-type rotary distribution injection pump is mounted on the
side of the cylinder block and driven by the gear train. The injection pump
performs three functions: generating injection pressure, metering the precise
quantity of fuel, and distributing fuel to each cylinder in the correct firing
order. The pump incorporates a mechanical governor that regulates fuel delivery
based on engine speed and load, as well as a cold-start device that advances
injection timing when the engine is cold.
High-pressure steel injection lines connect the pump to nozzle-type injectors
mounted in the cylinder head. Each injector sprays fuel into the swirl chamber,
where atomization occurs. A manual primer pump is integrated into the fuel
system to facilitate bleeding air after filter changes or fuel system service. A
fuel filter with an integrated water separator is mounted in the fuel supply
line to remove contaminants.
Injection Type: Mechanical indirect injection.
Injection Pump: Rotary distribution pump (Bosch VE or Zexel equivalent).
Injection Timing: 8-10 degrees before top dead center (static).
Injection Pressure (nozzle opening): 10.8-12.8 MPa (1,566-1,856 psi).
Fuel Requirement: Diesel fuel with minimum cetane number of 45.
Fuel Filter: Replaceable cartridge type with integrated water separator and
primer pump.
The lubrication system is a fully pressurized, wet-sump
design engineered for the sustained high-load operation of a heavy-duty diesel
engine. A gear-type oil pump, mounted to the front of the crankshaft and driven
by the gear train, draws lubricant from a large-capacity oil pan through a mesh
strainer. A full-flow, replaceable oil filter is mounted externally, with an
integral bypass valve that allows oil flow to continue if the filter becomes
restricted.
Pressurized oil is distributed through internal galleries to the crankshaft main
bearings, connecting rod bearings, camshaft bearings, and timing gear train. A
water-cooled oil cooler is integrated into the system to stabilize oil
temperature under sustained high-load operation. The large oil capacity supports
extended service intervals in commercial applications. A pressure relief valve
maintains system pressure within operational limits.
Oil Type: Diesel-rated SAE 15W-40 or 10W-30 (API CD, CE, or higher).
Oil Capacity: 8.5-10.5 liters (9.0-11.1 US qt), depending on oil pan
configuration.
Oil Pressure (at 2,000 rpm): 294-392 kPa (42.6-56.9 psi).
Oil Pressure (at idle): 98 kPa (14.2 psi) minimum.
Oil Pump Type: Gear-type, gear train-driven.
The cooling system is a pressurized, liquid-cooled
design engineered to manage the thermal load of a 4.2-liter inline-six diesel
engine in heavy-duty applications. A large-capacity cross-flow aluminum or
copper radiator with a viscous-driven mechanical fan provides cooling capacity
for sustained high-load operation. A centrifugal-type water pump, driven by the
gear train, circulates coolant through the cylinder block, cylinder head, and
heater core.
A wax-pellet thermostat regulates coolant flow to maintain optimal operating
temperature, with a bypass circuit that allows rapid warm-up. The cooling system
is designed to provide uniform cooling across all six cylinders, minimizing
thermal distortion of the cast iron components. A coolant recovery tank is
integrated to maintain system pressure and prevent coolant loss.
Coolant Type: Ethylene-glycol based antifreeze with corrosion inhibitors.
Coolant Capacity: 12.0-14.0 liters (12.7-14.8 US qt).
Thermostat Opening Temperature: 76-82 °C (169-180 °F).
Thermostat Full-Open Temperature: 90 °C (194 °F).
Radiator Cap Pressure: 88-108 kPa (12.8-15.7 psi).
Water Pump Type: Centrifugal, gear train-driven.
Intake System: Air is drawn through a heavy-duty
dry-type paper element air filter with a restriction indicator. The intake
manifold is a cast iron design with a plenum chamber sized to ensure even air
distribution to all six cylinders.
Exhaust System: Cast iron exhaust manifold with individual runners collecting
into a single outlet. The manifold is designed to withstand high exhaust gas
temperatures encountered under sustained load.
Timing Drive: The camshaft and injection pump are driven directly by a train of
precision-cut helical gears from the crankshaft. The gear train is housed in a
cast iron front cover and consists of a crankshaft gear, an idler gear, a
camshaft gear, and an injection pump drive gear. This gear-driven system
requires no periodic replacement and provides precise, permanent timing
synchronization.
Overall Length: 1,050 mm (41.3 in).
Overall Width: 630 mm (24.8 in).
Overall Height: 820 mm (32.3 in).
Dry Weight (complete engine): 295-310 kg (650-683 lb).
Oil Change Interval: 5,000 km (3,000 mi) under normal
commercial operating conditions; 3,000 km (1,800 mi) under severe conditions.
Oil Filter Change: At every oil change. Engine Coolant Replacement: 60,000 km
(40,000 mi) or 2 years. Fuel Filter Replacement: 20,000 km (12,000 mi) or as
indicated by water separator inspection. Fuel Water Separator Drain: Every 5,000
km (3,000 mi) to remove accumulated water.
Glow Plug Inspection: 60,000 km (40,000 mi) for resistance and heating
performance. Valve Clearance Adjustment: Inspect and adjust every 20,000 km
(12,000 mi). Intake: 0.25-0.35 mm (0.010-0.014 in) cold. Exhaust: 0.35-0.45 mm
(0.014-0.018 in) cold. Drive Belt (Accessory) Inspection: Every 10,000 km (6,000
mi) for tension, cracking, and glazing. Air Filter Replacement: 30,000 km
(18,000 mi) or as indicated by restriction indicator. Injection Pump Timing:
Should be verified after any service affecting gear train alignment using
dynamic timing equipment or dial indicator method.
Cylinder Head Bolts (M12 x 1.75): 40 Nm (30 lb-ft).
Cylinder Head Bolts (M12 x 1.75): 80 Nm (59 lb-ft).
Cylinder Head Bolts (M12 x 1.75): 120 Nm (89 lb-ft).
Main Bearing Cap Bolts (M12 x 1.75): 60 Nm (44 lb-ft).
Connecting Rod Cap Bolts (M10 x 1.25): 40 Nm (30 lb-ft).
Camshaft Bearing Cap Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft).
Rocker Arm Shaft Bolts (M10 x 1.25): 35-40 Nm (26-30 lb-ft).
Intake Manifold Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft).
Exhaust Manifold Nuts (M8 x 1.25): 20-25 Nm (15-18 lb-ft).
Glow Plugs: 15-20 Nm (11-15 lb-ft).
Oil Pan Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft).
Water Pump Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft).
Injection Pump Mounting Nuts (M8 x 1.25): 20-25 Nm (15-18 lb-ft).
Injection Line Nuts: 20-25 Nm (15-18 lb-ft).
Crankshaft Pulley Bolt (M20 x 1.5): 350-400 Nm (258-295 lb-ft).
Flywheel Bolts (M12 x 1.25): 60 Nm (44 lb-ft).
Front Gear Train Cover Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft).
The Nissan TD42 engine was utilized extensively across
Nissan’s heavy-duty off-road vehicle, commercial truck, and bus lineup
throughout the late 1980s through the mid-2000s, primarily in markets outside
North America.
Nissan Patrol (GQ / Y60): 1987-1997 model years (4.2-liter diesel variants).
Nissan Patrol (GU / Y61): 1997-2007 model years (4.2-liter diesel variants).
Nissan Safari (Y60, Y61): 1987-2007 model years (Japanese Domestic Market).
Ford Maverick (Australia): 1988-1994 model years (rebadged Nissan Patrol GQ).
Nissan Civilian (W40, W41): 1988-2004 model years (bus applications).
Nissan Atlas (F22, F23): 1988-1995 model years (light truck applications).
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