Renault F8Q Specifications
| Engine Model: Renault F8Q |
| Engine Type: 4-cycle inline 4-cylinder SOHC 8-valve liquid-cooled diesel |
| Total Displacement: 114.1 cu.in (1.87 L) |
| Rated Engine Power: 64-95 Hp (47-70 kW) at 4500 rpm |
| Fuel System Type: Indirect injection |
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The Renault F8Q is a 1.9-liter inline-four diesel
engine belonging to the F-Type engine family, produced from the late 1980s
through the early 2000s. This powerplant served as the backbone of Renault’s
diesel offerings across two decades, gaining recognition for its robust
mechanical construction, field-serviceable design, and exceptional longevity.
The F8Q was offered in both naturally aspirated and turbocharged configurations,
with the turbocharged variants - designated F8Q Turbo - delivering substantially
improved performance while maintaining the durability characteristics that made
the naturally aspirated version a favorite among high-mileage drivers.
The engine’s architecture adhered to a conservative engineering philosophy
prioritizing reliability over advanced technology. The cast iron cylinder block
and aluminum cylinder head construction provided thermal stability and
resistance to distortion under sustained load. The indirect injection (IDI) fuel
system utilized pre-combustion chambers - swirl chambers - that promoted smooth
combustion, reduced noise, and permitted operation with a broad range of diesel
fuel qualities.
The SOHC valvetrain operated eight valves through a timing belt drive, with
mechanical valve adjustment requiring periodic inspection. The F8Q’s production
run coincided with the transition from purely mechanical injection systems to
electronically controlled pumps, with later variants receiving the “Epic”
injection pump to meet evolving emissions regulations. This engine powered a
wide range of Renault passenger cars, light commercial vehicles, and was
supplied to Mitsubishi and Volvo for joint-venture platforms.
The F8Q is a four-stroke, water-cooled diesel engine configured for transverse
or longitudinal mounting depending on vehicle application. The engine utilizes
indirect injection with pre-combustion chambers and mechanical or electronically
controlled injection.
Engine Type: Inline-4, 4-cycle, water-cooled, naturally aspirated or turbo
diesel.
Displacement: 1,870 cc (114.1 cu.in).
Bore: 80.0 mm (3.15 in).
Stroke: 93.0 mm (3.66 in).
Firing Order: 1-3-4-2.
Valvetrain: SOHC, 8-valve (2 valves per cylinder).
Naturally Aspirated
Compression Ratio: 21.5:1.
Maximum Power: 47-48 kW (64-65 hp) at 4,500 rpm.
Maximum Torque: 118-121 Nm (87-89 lb-ft) at 2,250 rpm.
Turbocharged
Compression Ratio: 20.5:1.
Maximum Power: 66-70 kW (90-95 hp) at 4,250 rpm.
Maximum Torque: 175-190 Nm (129-140 lb-ft) at 2,000 rpm.
Aspiration: Single turbocharger w/o intercooler or w/intercooler.
The cylinder block is manufactured from gray cast iron
using a permanent mold casting process, selected for its dimensional stability,
wear resistance, and ability to withstand the elevated cylinder pressures of
diesel operation. The block features a deep-skirt design with the casting
extending below the crankshaft centerline, providing a rigid foundation for the
rotating assembly.
The cylinder bores are machined directly into the iron casting with a honed
surface finish optimized for cast iron piston ring packs. The block incorporates
a siamesed bore configuration where adjacent cylinders share common walls,
reducing overall engine length and increasing structural rigidity. Water jackets
surround each cylinder bore, with coolant flow directed from the water pump into
the block before rising into the cylinder head.
The crankcase incorporates five main bearing supports with the bearing webs
integrated into the block casting. Main bearing caps are manufactured from cast
iron and secured with two bolts per cap. The block includes mounting bosses for
the injection pump, which is gear-driven from the crankshaft, and provisions for
the mechanical fuel lift pump. A cast aluminum or stamped steel oil pan is
bolted to the lower crankcase flange.
Block Material: Gray cast iron
Bore Diameter: 80.0 mm (3.15 in)
Cylinder Configuration: Inline, siamesed bores
Main Bearing Quantity: 5
Main Bearing Cap Design: Cast iron, two-bolt attachment
The cylinder head is constructed from aluminum alloy
using a permanent mold casting process, selected for its favorable thermal
conductivity relative to cast iron. The cross-flow port configuration places
intake ports on one side and exhaust ports on the opposite side. The SOHC
valvetrain operates eight valves - two per cylinder - via rocker arms that pivot
on a single rocker shaft.
The combustion system employs indirect injection (IDI) with pre-combustion
chambers (swirl chambers) located in the cylinder head for each cylinder. Each
pre-combustion chamber is a pear-shaped or spherical cavity machined into a
separate insert pressed into the head, with a narrow throat connecting the
pre-chamber to the main combustion chamber. The fuel injector nozzle protrudes
into the pre-chamber, where initial fuel evaporation and ignition occur before
the burning mixture expands into the main chamber. This design reduces
combustion noise, permits lower injection pressures, and allows operation with a
wider range of diesel fuel qualities compared to direct injection systems.
Valve actuation is accomplished via rocker arms operating on a common shaft.
Valve clearance adjustment is performed manually using a screw-and-locknut
adjuster at the rocker arm contact point. The camshaft is supported in bearing
journals machined directly into the cylinder head casting, with bearing caps of
identical construction. The cylinder head incorporates pressed-in valve seat
inserts, with exhaust seats manufactured from a nickel-based alloy to withstand
elevated temperatures.
Head Material: Aluminum alloy
Valve Configuration: SOHC, 8-valve (2 valves per cylinder)
Intake Valve Diameter: 39.0 mm (1.54 in)
Exhaust Valve Diameter: 33.0 mm (1.30 in)
Valve Stem Diameter: 8.0 mm (0.31 in)
Valve Seat Angle: 45 degrees
Camshaft Drive: Timing belt with automatic tensioner
Valve Clearance (Cold, Intake): 0.20-0.30 mm (0.008-0.012 in)
Valve Clearance (Cold, Exhaust): 0.30-0.40 mm (0.012-0.016 in)
Pre-Combustion Chamber: Swirl chamber per cylinder with pressed insert
Interference Engine: Yes - valve-to-piston contact occurs if timing belt fails
The lubrication system is a fully pressurized, wet-sump
design with a gear-type oil pump mounted internally within the timing case and
driven by the crankshaft nose. The oil pump utilizes a pair of meshing gears to
generate flow with positive displacement characteristics.
Oil is drawn from the stamped steel or cast aluminum oil pan through a mesh
strainer 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 shaft, and turbocharger bearings on turbocharged
variants. A pressure relief valve bypasses excess oil flow back to the oil pan
when system pressure exceeds the calibrated limit. Turbocharged variants
incorporate an additional oil feed line supplying the turbocharger center
housing bearings, with a restricted orifice controlling flow rate.
Oil Type: Diesel engine oil API CD, CE, or CF; SAE 15W-40 or 20W-50 viscosity
Oil Capacity (with filter): 4.5-5.0 L (4.8-5.3 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
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, and radiator. The
system is sized to accommodate the thermal demands of both naturally aspirated
and turbocharged configurations.
A wax-pellet thermostat mounted in a housing on the 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 or down-flow copper-brass or aluminum-plastic
construction depending on vehicle application. A viscous-drive fan or electric
fan provides forced airflow through the radiator. Turbocharged variants may
incorporate an additional oil cooler - a water-to-oil heat exchanger - mounted
on the cylinder block adjacent to the oil filter. The cooling system
incorporates an expansion tank with a pressure-rated cap.
Coolant Type: Ethylene-glycol based antifreeze meeting Renault specification
Coolant Capacity: 6.5-7.5 L (6.9-7.9 US qt) depending on radiator configuration
Thermostat Opening Temperature: 82-88 °C (180-190 °F)
Radiator Cap Pressure: 90-110 kPa (13-16 psi)
Water Pump Type: Centrifugal, belt-driven
Intake System: The intake system incorporates a
paper-element air cleaner with an integrated restriction indicator. Filtered air
enters the intake manifold through a cast aluminum or composite plastic plenum.
Turbocharged variants incorporate a single turbocharger - a Garrett or KKK unit
- mounted on the exhaust manifold. Compressed air passes through an air-to-air
intercooler on select intercooled variants before entering the intake manifold.
Exhaust System: The exhaust manifold is a cast iron single-piece design
collecting exhaust gases from all four cylinders. Turbocharged variants
incorporate the turbocharger flange integrated into the manifold casting. The
exhaust system incorporates a catalytic converter on vehicles equipped for
markets with emissions regulations requiring such devices. Naturally aspirated
variants may utilize an oxidation catalyst.
Timing Drive: The engine utilizes a rubber timing belt with internal fabric
reinforcement to drive the camshaft from the crankshaft sprocket. The belt also
drives the water pump on most configurations. A spring-loaded automatic
tensioner pulley maintains belt tension. The F8Q is an interference engine;
timing belt failure results in piston-to-valve contact causing significant
engine damage.
Overall Length: 620 mm (24.4 in)
Overall Width: 590 mm (23.2 in)
Overall Height: 720 mm (28.3 in)
Dry Weight (complete engine): 155 kg (342 lb)
Engine Oil Change: 7,500-10,000 km (4,700-6,200 mi) or
1 year.
Engine Oil Filter Change: At every oil change.
Timing Belt Replacement: 80,000-120,000 km (50,000-75,000 mi) or 5 years.
Timing Belt Tensioner Inspection: Replace with timing belt.
Valve Clearance Inspection: Every 40,000 km (25,000 mi); adjust as required.
Fuel Filter Replacement: 20,000 km (12,400 mi) or 1 year.
Air Filter Replacement: 30,000 km (18,600 mi) or as indicated.
Coolant Replacement: 40,000 km (25,000 mi) or 2 years.
Drive Belt (Accessory) Inspection: Every 15,000 km (9,300 mi).
Injection Pump Timing: Inspect following timing belt replacement; adjust as
required.
Injector Service: 80,000 km (50,000 mi) inspection and calibration.
Cylinder Head Bolts (M12 x 1.5), 1st pass: 40 Nm (30
lb-ft)
Cylinder Head Bolts (M12 x 1.5), 2nd pass: 80 Nm (59 lb-ft)
Cylinder Head Bolts (M12 x 1.5), 3rd pass: 120 Nm (89 lb-ft)
Cylinder Head Bolts (M12 x 1.5), Final pass: 150 Nm (111 lb-ft)
Main Bearing Cap Bolts (M12 x 1.5), 1st pass: 40 Nm (30 lb-ft)
Main Bearing Cap Bolts (M12 x 1.5), Final pass: 80-90 Nm (59-66 lb-ft)
Connecting Rod Cap Bolts (M9 x 1.25), 1st pass: 20 Nm (15 lb-ft)
Connecting Rod Cap Bolts (M9 x 1.25), Final pass: 45-50 Nm (33-37 lb-ft)
Camshaft Bearing Cap Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft)
Rocker Shaft Bolts (M10 x 1.25): 40-45 Nm (30-33 lb-ft)
Intake Manifold Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft)
Exhaust Manifold Nuts (M8 x 1.25): 25-30 Nm (18-22 lb-ft)
Fuel Injector Holders (M24 x 1.5): 70-80 Nm (52-59 lb-ft)
High-Pressure Fuel Line Fittings: 20-25 Nm (15-18 lb-ft)
Oil Pan Bolts (M8 x 1.25): 15-20 Nm (11-15 lb-ft)
Water Pump Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft)
Timing Belt Tensioner Bolt (M10 x 1.25): 25-30 Nm (18-22 lb-ft)
Crankshaft Pulley Bolt (M16 x 1.5), 1st pass: 100 Nm (74 lb-ft)
Crankshaft Pulley Bolt (M16 x 1.5), Final pass: 120-140 Nm (89-103 lb-ft)
Flywheel Bolts (M10 x 1.25): 65-75 Nm (48-55 lb-ft)
The Renault F8Q engine was deployed across a wide range
of Renault passenger cars, light commercial vehicles, and was supplied to
joint-venture manufacturing partners.
Renault Clio I and II: 1991-2001 model years. The F8Q was offered in both
naturally aspirated and turbocharged configurations in the Clio I (Phase II and
III) and Clio II. Naturally aspirated variants served as the entry-level diesel,
while the F8Q Turbo - designated as the 1.9 dT - provided enhanced performance.
Applications included five-door, three-door, and van body styles.
Renault 19: 1988-1996 model years. The F8Q was offered in the Renault 19
hatchback and sedan, with naturally aspirated and turbocharged variants
available throughout the production run.
Renault Megane I: 1995-2003 model years. The F8Q served as the diesel powertrain
for the first-generation Megane, with both naturally aspirated and turbocharged
configurations offered in hatchback, sedan, coupe, and estate body styles.
Turbocharged variants were designated 1.9 dT.
Renault Kangoo I: 1997-2002 model years. The F8Q naturally aspirated variant was
offered in the Kangoo light commercial vehicle and passenger van, providing
durable power for urban delivery applications.
Renault Laguna I: 1993-1998 model years. The F8Q was offered in the
first-generation Laguna as the diesel powertrain option, with naturally
aspirated variants in entry-level trims and the F8Q Turbo in
higher-specification models.
Mitsubishi Carisma: 1995-2004 model years. The F8Q was supplied to Mitsubishi
for installation in the Carisma compact sedan and hatchback, produced under a
joint-venture agreement between Mitsubishi and Volvo. Both naturally aspirated
and turbocharged variants were offered.
Volvo S40 / V40: 1995-2004 model years. The F8Q was installed in the
first-generation S40 sedan and V40 estate as the diesel powertrain option,
supplied through the Mitsubishi-Volvo joint venture that produced these models
at the NedCar facility in the Netherlands.
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