Nissan TD42T Specifications
| Engine Model: Nissan TD42T |
| Engine Type: 4-cycle 6-cylinder OHV 12-valve turbocharged liquid-cooled diesel |
| Total Displacement: 254.4 cu.in (4.17 L) |
| Rated Engine Power: 143-158 Hp (107-118 kW) at 4000 rpm |
| Fuel System Type: Indirect injection |
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The Nissan TD42T is a 4.2-liter inline-six turbocharged
diesel engine, representing the factory-boosted evolution of the naturally
aspirated TD42 that gained renown for exceptional durability in Nissan’s
heavy-duty commercial and off-road platforms. Introduced in the early 1990s,
this powerplant was engineered to provide enhanced power and torque output while
maintaining the structural integrity and longevity that established the TD42 as
a benchmark in diesel reliability.
The TD42T achieved its performance increase through the addition of a Garrett
T25 series turbocharger, reinforced internal components, and the incorporation
of piston oil squirters - features absent from the naturally aspirated variant.
The engine’s architecture adhered to the overengineered design philosophy that
defined the TD series. The cast iron cylinder block and cylinder head
construction provided the thermal stability and rigidity required for sustained
turbocharged operation under heavy loads. The gear-driven timing system
eliminated the maintenance concerns associated with belt or chain drives,
contributing to the engine’s reputation for service intervals exceeding 500,000
km (310,000 mi) when properly maintained.
The TD42T utilized an indirect injection (IDI) fuel system with a pre-combustion
chamber design, prioritizing smooth combustion, reduced noise, and compatibility
with lower-quality diesel fuels encountered in global markets. This engine
became the preferred powertrain for the Nissan Patrol Safari in the Japanese
domestic market and later for export Patrol models, establishing itself as a
coveted option among off-road enthusiasts who valued its massive low-end torque
and field-serviceable design.
The TD42T is a four-stroke, water-cooled, turbocharged diesel engine configured
for longitudinal mounting in rear-wheel-drive and four-wheel-drive vehicle
architectures. The engine utilizes indirect injection with a pre-combustion
chamber in each cylinder.
Engine Type: Inline-6, 4-cycle, water-cooled, turbocharged diesel.
Displacement: 4,169 cc (254.4 cu.in).
Bore: 96.0 mm (3.78 in).
Stroke: 96.0 mm (3.78 in).
Compression Ratio: 21.0:1.
Firing Order: 1-5-3-6-2-4.
Valvetrain: OHV (Overhead Valve), 12-valve (2 valves per cylinder).
Aspiration: Single turbocharger (Garrett T25 series) with intercooler.
Maximum Power: 107-118 kW (143-158 hp) at 4,000 rpm.
Maximum Torque: 330-335 Nm (243-247 lb-ft) at 2,000 rpm.
Redline: 4,500 rpm.
Governed Speed: 4,500 rpm maximum no-load.
Injection Pump: Inline injection pump with mechanical governor.
The cylinder block is manufactured from gray cast iron
with a high-nickel content, selected for its wear resistance and dimensional
stability under the elevated cylinder pressures generated by turbocharged diesel
operation. The block features a deep-skirt design extending below the crankshaft
centerline, with the main bearing caps recessed into the crankcase structure.
This configuration provides exceptional rigidity and minimizes bore distortion
under high combustion loads.
The cylinder bores are machined directly into the iron casting with a
plateau-honed finish optimized for the cast iron piston ring packs. The block
incorporates a siamesed bore configuration where adjacent cylinders share common
walls, increasing structural rigidity and reducing overall engine length. Water
jackets surround each cylinder bore with coolant flow directed preferentially to
the upper cylinder area, where thermal loading is highest. The crankcase is
reinforced with transverse ribs cast into the external surfaces to dampen
vibration and noise emissions.
A distinguishing feature of the TD42T relative to the naturally aspirated TD42
is the inclusion of piston oil squirters. These dedicated nozzles are mounted in
the crankcase and direct a continuous stream of engine oil to the underside of
each piston crown, managing thermal loads under sustained boost conditions. The
block incorporates the mounting provisions for the gear-driven timing system,
with a cast iron timing case at the front accepting the camshaft, injection
pump, and accessory drive gears.
Block Material: High-nickel cast iron.
Bore Diameter: 96.0 mm (3.78 in).
Cylinder Configuration: Inline, siamesed bores.
Main Bearing Quantity: 7.
Main Bearing Cap Design: Cast iron, two-bolt attachment.
Piston Cooling: Oil squirters (jets) directed at each piston undercrown.
The cylinder head is manufactured from cast iron, a
material selection that complements the cast iron block and provides thermal
expansion characteristics compatible with the head gasket and fastening system.
The overhead valve (OHV) arrangement positions the camshaft within the cylinder
block, with pushrods transmitting motion to the rocker arms that actuate the
valves. This configuration reduces the reciprocating mass at the cylinder head
and permits the use of the gear-driven timing system.
The combustion system employs indirect injection (IDI) with a pre-combustion
chamber (swirl chamber) located in the cylinder head for each cylinder. The
pre-combustion chamber is a spherical or pear-shaped cavity that receives the
fuel injector nozzle, with a narrow throat connecting the pre-chamber to the
main combustion chamber. This design promotes initial fuel evaporation and
ignition in the pre-chamber before the burning mixture expands into the main
chamber, reducing combustion noise and permitting operation with a broader range
of diesel fuel qualities.
The valves are arranged in a linear orientation along the cylinder head
centerline, with each cylinder having one intake valve and one exhaust valve.
Valve seats are pressed-in inserts of heat-resistant material, with intake seats
of sintered iron and exhaust seats of a nickel-based alloy. Valve guides are
cast iron inserts pressed into the head. The rocker arm assembly consists of a
rocker shaft supported by pedestals cast into the head, with individual forged
steel rocker arms actuating each valve. Valve clearance adjustment is
accomplished via screw-and-locknut adjusters at the pushrod contact point.
Head Material: Cast iron.
Valve Configuration: OHV, 12-valve (2 valves per cylinder).
Intake Valve Diameter: 44.0 mm (1.73 in).
Exhaust Valve Diameter: 38.0 mm (1.50 in).
Valve Stem Diameter: 9.0 mm (0.35 in).
Valve Seat Angle: 45 degrees.
Valve Clearance (Cold, Intake): 0.35-0.45 mm (0.014-0.018 in).
Valve Clearance (Cold, Exhaust): 0.45-0.55 mm (0.018-0.022 in).
Camshaft Drive: Helical-cut gear train from crankshaft.
Pre-Combustion Chamber: Spherical swirl chamber per cylinder.
The fuel system is a mechanically controlled indirect
injection design centered around an inline injection pump. The pump -
manufactured by Zexel (formerly Diesel Kiki) or Bosch depending on production
source - is a six-cylinder, inline, jerk-type pump with a mechanical governor.
The governor controls engine speed by regulating fuel delivery based on
accelerator pedal position and engine speed feedback, providing stable idling
and governed maximum speed control.
The injection pump is driven by the gear train at the front of the engine,
synchronized to the crankshaft and camshaft. Each cylinder has a dedicated
plunger and barrel assembly within the pump, generating high-pressure fuel
pulses delivered through individual high-pressure fuel lines to the injectors.
The injectors are of the pintle or multi-hole nozzle type, positioned in the
cylinder head with the nozzle tip protruding into the pre-combustion chamber.
A feed pump integrated into the injection pump draws fuel from the tank through
a water-separating primary filter and delivers it to the injection pump inlet. A
secondary fuel filter of the spin-on type is mounted between the feed pump and
injection pump. Excess fuel from the injection pump and injector leak-off
returns to the fuel tank through a return line.
Turbocharged applications incorporate a boost compensator (aneroid) device on
the injection pump. This device senses intake manifold pressure and adjusts fuel
delivery under boost conditions, enriching the fuel mixture when positive
manifold pressure is present to maintain appropriate air-fuel ratios.
Injection Type: Indirect injection (IDI) with inline injection pump.
Injection Pump Type: Inline 6-cylinder jerk pump with mechanical governor.
Injector Nozzle Type: Pintle or multi-hole, pre-chamber configuration.
Injection Pressure: 12,000-15,000 kPa (1,740-2,180 psi) at nozzle opening.
Fuel Filtration: Primary water-separating filter plus secondary spin-on filter.
Boost Compensator: Yes - aneroid device on injection pump.
Fuel Requirement: Diesel fuel meeting EN 590 or equivalent specification; min
cetane 45.
The lubrication system is a fully pressurized, wet-sump
design with a gear-type oil pump mounted internally at the front of the engine
and driven by the crankshaft gear. The oil pump utilizes a pair of meshing gears
to generate flow with positive displacement characteristics.
Oil is drawn from the cast aluminum or stamped steel oil pan through a
strainer-type pickup positioned at the sump’s lowest point. Pressurized oil
passes through a full-flow, replaceable oil filter mounted externally on the
cylinder block. The filter incorporates a bypass valve that permits oil flow to
continue if the filter element becomes restricted. From the filter, oil enters
the main oil gallery cast longitudinally through the cylinder block, supplying
the crankshaft main bearings, connecting rod bearings, camshaft bearings, rocker
arm assemblies, and turbocharger bearings.
The TD42T lubrication system incorporates additional oil passages dedicated to
the piston cooling jets. These jets are supplied from the main oil gallery
through calibrated orifices that maintain consistent flow to each piston
regardless of oil pressure fluctuations. The turbocharger is supplied through a
dedicated oil feed line with a restricted orifice controlling flow rate, with an
oil drain line returning lubricant to the oil pan.
An oil cooler - a water-to-oil heat exchanger - is mounted on the cylinder block
adjacent to the oil filter. This cooler maintains oil temperature within
operational limits under sustained high-load operation. A pressure relief valve
bypasses excess oil flow back to the oil pan when system pressure exceeds the
calibrated limit.
Oil Type: High-quality diesel engine oil API CF-4, CG-4, or CI-4; SAE 15W-40,
20W-50.
Oil Capacity (with filter): 9.8-10.5 L (10.4-11.1 US qt) depending on oil pan
configuration.
Oil Pressure (at idle, warm): 100-150 kPa (15-22 psi).
Oil Pressure (at 3,000 rpm): 350-450 kPa (51-65 psi).
Oil Pump Type: Gear-type, crankshaft-driven.
Oil Cooler: Water-to-oil heat exchanger integrated with oil filter housing.
Piston Cooling: Dedicated oil jets per cylinder.
The cooling system is a pressurized, liquid-cooled
design with a belt-driven centrifugal water pump mounted on the front of the
cylinder block. The water pump impeller circulates coolant through the cylinder
block water jackets, cylinder head passages, heater core, radiator, and oil
cooler. The system is sized to accommodate the thermal demands of turbocharged
operation under heavy loads.
A wax-pellet thermostat mounted in a housing on the water pump inlet or cylinder
head outlet regulates coolant flow to the radiator. The thermostat begins
opening at a calibrated temperature and achieves full opening within a defined
temperature range. A bypass circuit permits coolant circulation within the
engine during warm-up, bypassing the radiator until the thermostat opens.
The radiator is a cross-flow copper-brass or aluminum-plastic construction with
a high-efficiency core designed for the cooling demands of diesel operation. A
viscous-drive fan mounted on the water pump pulley provides forced airflow
through the radiator and intercooler, with a fan shroud ensuring airflow through
the entire core area. The cooling system incorporates a separate expansion tank
with a pressure-rated cap to manage coolant expansion and system pressurization.
Coolant Type: Ethylene-glycol based antifreeze meeting Nissan specification.
Coolant Capacity: 13.0-14.5 L (13.7-15.3 US qt) depending on radiator
configuration.
Thermostat Opening Temperature: 82 °C (180 °F).
Thermostat Full Opening Temperature: 95 °C (203 °F).
Radiator Cap Pressure: 110-130 kPa (16-19 psi).
Water Pump Type: Centrifugal, belt-driven.
| Intake and Exhaust Systems |
Intake System: The intake system incorporates a
paper-element air cleaner with an integrated restriction indicator. Filtered air
enters the turbocharger compressor housing, where compression raises intake air
temperature. Compressed air passes through an air-to-air intercooler (charge air
cooler) mounted in front of the radiator on intercooled variants, reducing
intake air temperature before entering the intake manifold. The intake manifold
is a cast iron or fabricated steel design with equal-length runners to each
cylinder.
Exhaust System: The exhaust manifold is a cast iron, six-into-one design
collecting exhaust gases from all cylinders into a single inlet for the
turbocharger turbine housing. The turbocharger is a Garrett T25 series unit with
a wastegate that diverts exhaust flow around the turbine to control boost
pressure. The exhaust system incorporates a single or dual exhaust pipe
configuration depending on vehicle application.
Turbocharger: Single Garrett T25 series turbocharger
with wastegate. Compressor housing and turbine A/R ratios optimized for low-end
torque response. Maximum boost pressure: 80-100 kPa (11.6-14.5 psi) depending on
application.
Timing Drive: A helical-cut gear train serves as the primary timing drive. A
gear on the crankshaft drives an idler gear, which in turn drives the camshaft
gear and the injection pump drive gear. This gear-driven system requires no
periodic replacement and provides precise synchronization between the
crankshaft, camshaft, and injection pump throughout the engine’s service life.
Overall Length: 980 mm (38.6 in).
Overall Width: 720 mm (28.3 in).
Overall Height: 860 mm (33.9 in).
Dry Weight (complete engine): 380 kg (838 lb).
Engine Oil Change: 5,000-10,000 km (3,100-6,200 mi) or
6 months.
Engine Oil Filter Change: At every oil change.
Fuel Filter Replacement: 20,000 km (12,400 mi) or 1 year.
Air Filter Element Replacement: When restriction indicator shows or 20,000 km
(12,400 mi).
Coolant Replacement: 80,000 km (49,700 mi) or 4 years.
Valve Clearance Adjustment: Every 40,000 km (25,000 mi).
Timing Gear Inspection: Gear backlash inspection at major overhaul.
Drive Belt (Accessory) Replacement: 60,000 km (37,300 mi).
Injection Pump Timing: Inspect every 80,000 km (49,700 mi); adjust as required.
Injector Service: 100,000 km (62,000 mi) inspection and calibration.
Cylinder Head Bolts (M14 x 1.5), 1st pass: 50 Nm (37
lb-ft)
Cylinder Head Bolts (M14 x 1.5), 2nd pass: 100 Nm (74 lb-ft)
Cylinder Head Bolts (M14 x 1.5), 3rd pass: 150 Nm (111 lb-ft)
Main Bearing Cap Bolts (M14 x 1.5), 1st pass: 70 Nm (52 lb-ft)
Main Bearing Cap Bolts (M14 x 1.5), Final pass: 130-140 Nm (96-103 lb-ft)
Connecting Rod Cap Bolts (M11 x 1.25): 30 Nm (22 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): 50-60 Nm (37-44 lb-ft)
Intake Manifold Bolts (M10 x 1.25): 40-50 Nm (30-37 lb-ft)
Exhaust Manifold Nuts (M10 x 1.25): 50-60 Nm (37-44 lb-ft)
Turbocharger Mounting Nuts (M10 x 1.25): 50-60 Nm (37-44 lb-ft)
Injection Pump Gear Bolt (M12 x 1.25): 70-80 Nm (52-59 lb-ft)
Fuel Injector Holder (M24 x 1.5): 70-80 Nm (52-59 lb-ft)
High-Pressure Fuel Line Fittings: 25-30 Nm (18-22 lb-ft)
Oil Pan Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft)
Water Pump Bolts (M10 x 1.25): 30-40 Nm (22-30 lb-ft)
Crankshaft Pulley Bolt (M20 x 1.5): 200 Nm (148 lb-ft)
Flywheel Bolts (M12 x 1.5): 50 Nm (37 lb-ft)
Engine Mounting Bracket Bolts (M12 x 1.5): 80-90 Nm (59-66 lb-ft)
The Nissan TD42T engine was deployed across a range of
heavy-duty commercial vehicles, off-road platforms, and bus applications, with a
concentration in the Japanese domestic market and export markets where diesel
durability was prioritized.
Nissan Patrol (GQ / Y60): 1993-1997 model years. The TD42T was introduced in the
GQ Patrol as a factory-turbocharged option, primarily in the Safari trim level
within Japan. This application featured the TD42T with intercooler on select
variants, providing enhanced power and torque for off-road use. The engine was
paired with a five-speed manual transmission or a four-speed automatic.
Nissan Patrol (GU / Y61): 1997-2002 model years. The TD42T continued in the GU
Patrol following the Y61 chassis introduction. Production extended through the
early 2000s before being superseded by common-rail diesel engines in export
markets. The GU application incorporated refinements to the intercooler system
and engine management.
Nissan Safari (Y60 / Y61): 1993-2002 model years. The Safari - the Japanese
domestic market designation for the Patrol - received the TD42T as the premium
powertrain option. Safari models were distinguished by heavy-duty chassis
components and equipment suited for the Japanese market, with the TD42T
providing the torque required for mountainous terrain.
Nissan Civilian (W41 Bus): 1999-2004 model years. The TD42T was installed in the
Civilian medium-duty bus, where its durability and torque characteristics suited
passenger transport applications. The bus configuration utilized a modified
engine calibration with a lower governed speed and revised injection pump
settings for enhanced fuel economy and reduced noise.
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