Isuzu G200W Specifications
| Engine Model: Isuzu G200W |
| Engine Type: 4-stroke in-line 4-cylinder 8-valve DOHC liquid-cooled gasoline |
| Total Displacement: 118.9 cu.in (1.95 L) |
| Rated Engine Power: 133 Hp (99 kW) at 6200 rpm |
| Fuel System Type: Electronic fuel injection |
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The Isuzu G200W is a 2.0-liter, inline
4-cylinder petrol engine representing one of Isuzu's premier
dual-overhead-camshaft (DOHC) designs from the late 1970s and early
1980s. Developed as the performance flagship within Isuzu's G-series
engine family, the G200W powered the most sporting versions of the Isuzu
117 Coupe and the early Isuzu Piazza (Impulse).
Unlike the single overhead camshaft G200Z variant, the G200W features a
DOHC valvetrain with eight valves - two per cylinder - driven by a
durable timing chain rather than a belt, a design choice that
prioritized longevity and reliability at high engine speeds. The engine
displaces 1,949 cc from a bore and stroke of 87.0 mm x 82.0 mm - an
oversquare configuration favoring higher-rpm power production. Equipped
with electronic fuel injection (EFI / I-TEC) in most applications, the
G200W produces 135 PS (99 kW) at 6,200 rpm and 167 Nm (123 lb-ft) of
torque at 5,000 rpm.
The engine was available with different intake manifold configurations:
the Piazza variants featured an "over the top" manifold design, while
the 117 Coupe versions used an "out right and forward" arrangement. The
G200W remains sought after by Isuzu enthusiasts, particularly as a
performance upgrade for the Isuzu Gemini ZZ, where its engine mounts
match earlier G-series installations.
Engine Code: G200W
Engine Family: Isuzu G-series
Configuration: Inline 4-cylinder, 4-stroke
Valvetrain: Double Overhead Camshaft (DOHC), 8 valves (2 per cylinder)
Valvetrain Drive: Timing chain
Displacement: 1949 cc (118.9 cu.in)
Bore: 87.0 mm (3.43 in)
Stroke: 82.0 mm (3.23 in)
Compression Ratio: 9.0:1
Firing Order: 1-3-4-2
Fuel System: Electronic Fuel Injection (EFI / I-TEC)
Maximum Power: 99 kW (133 hp) at 6200 rpm
Maximum Torque: 167 Nm (123 lb-ft) at 5000 rpm
Maximum Engine Speed: 6500-6800 rpm (fuel cut-off varies)
The cylinder block is constructed from cast iron, a material selection
providing the structural rigidity and wear resistance required for
sustained high-rpm operation. The block is a conventional design with
the cylinder bores machined directly into the cast iron casting without
removable liners. The crankshaft is manufactured from forged steel and
is supported by five main bearings.
The connecting rods are forged steel, suited to the engine's
performance-oriented design. The pistons are aluminum alloy with a
compression height optimized for the DOHC cylinder head’s combustion
chamber design. The G200W is not equipped with piston cooling jets, as
the naturally aspirated configuration and moderate compression ratio of
9.0:1 place lower thermal demands on the pistons compared to
forced-induction or high-compression designs.
The cylinder head is manufactured from aluminum alloy and houses a
Double Overhead Camshaft (DOHC) arrangement with two valves per
cylinder, totaling eight valves. The DOHC design separates intake and
exhaust camshaft functions, allowing optimized valve timing for each set
of valves without the compromises inherent in single camshaft designs.
The camshafts are driven by a timing chain - a durable alternative to
rubber timing belts - contributing to the engine's reputation for
long-term reliability. The valvetrain incorporates mechanical lash
adjusters (solid lifters), requiring periodic valve clearance inspection
and manual adjustment. The combustion chamber is a pent-roof design with
valves arranged at included angles to promote efficient flame
propagation.
The valve diameters are 44.0 mm (1.73 in) for intake and 38.0 mm (1.50
in) for exhaust, consistent with performance-oriented 2.0-liter engines
of the era. The cylinder head casting incorporates cross-flow intake and
exhaust passages, with the intake manifold positioned on one side and
the exhaust manifold on the opposite side.
The fuel system employs Electronic Fuel Injection (EFI), marketed by
Isuzu under the I-TEC designation. The system uses a central electronic
control unit managing fuel delivery based on inputs from engine sensors.
An electric fuel pump located within the fuel tank supplies pressurized
fuel to a fuel rail mounted on the intake manifold. The fuel rail
distributes fuel to four electronically controlled injectors positioned
near each intake port.
The intake manifold configuration varied by vehicle application. In the
Isuzu Piazza, the manifold featured an "over the top" design crossing
above the engine. In the 117 Coupe, the manifold was arranged "out right
and forward". A fuel pressure regulator maintains constant pressure
differential across the injectors. The EFI system includes a cold-start
injector in certain applications for enriched fuel delivery during
cranking and warm-up.
The lubrication system is a pressurized, full-flow wet-sump design
utilizing a gear-type oil pump mounted to the front of the crankshaft.
The oil pump draws fluid from a pressed-steel or aluminum oil pan, with
a total system capacity of 4.5-5.0 liters (4.8-5.3 qt) including the
filter. A spin-on, full-flow oil filter is mounted to the cylinder
block.
Recommended oil viscosity is 10W-30 or 20W-50 for warmer climates,
conforming to API SF, SG, or higher specifications. An oil pressure
switch activates a warning lamp if pressure falls below 0.5 bar (7 psi)
at idle. The lubrication system does not incorporate piston cooling
jets, as the naturally aspirated configuration and power output do not
require such thermal management.
The cooling system is a sealed, pressurized arrangement with a
belt-driven centrifugal water pump. The water pump is mounted to the
front of the cylinder block and is driven by the accessory drive belt.
Coolant circulates through the cast iron cylinder block and aluminum
cylinder head, with a wax-element thermostat regulating flow to the
front-mounted radiator.
The thermostat opening temperature is 82°C (180°F), with full opening at
approximately 95°C (203°F). A coolant bypass circuit allows circulation
during warm-up for faster engine temperature rise. A 0.9-1.1 bar (13-16
psi) radiator cap maintains system pressure. The system uses an ethylene
glycol-based coolant formulated for mixed-metal (cast iron and aluminum)
construction.
Ignition System: The ignition system employs a distributor-based design
with electronic advance control. A Hall-effect or magnetic pickup
distributor provides crankshaft position and engine speed information to
the ignition control module. A single ignition coil generates
high-voltage current distributed via the distributor rotor and
high-tension leads to the spark plugs. The ignition timing is adjustable
by rotating the distributor housing.
Intake and Exhaust Systems: The intake system includes a dry-type
pleated paper air filter housed in a plastic or metal air cleaner
assembly. The exhaust manifold is constructed from cast iron, with a
single outlet flange connecting to the exhaust system. The manifold
design is tuned to optimize exhaust gas flow from the DOHC cylinder
head.
Engine Management: The EFI system uses a dedicated Engine Control Unit
(ECU) integrating fuel injection control and, in some variants, ignition
timing control. The ECU processes inputs from the airflow meter (or
manifold absolute pressure sensor), throttle position sensor, coolant
temperature sensor, intake air temperature sensor, and oxygen sensor
(closed-loop variants) to determine injection duration.
Emission Control: Emission control systems vary by market and model
year. Closed-loop variants include an oxygen sensor, three-way catalytic
converter, positive crankcase ventilation (PCV), and evaporative
emission control with charcoal canister.
Overall Length: 620 mm (24.4 in).
Overall Width: 620 mm (24.4 in).
Overall Height: 680 mm (26.8 in).
Dry Weight (without ancillaries): 135 kg (298 lb).
Dry Weight (fully dressed with manifolds, alternator, starter, and
flywheel): 155 kg (342 lb).
Engine Oil Capacity (with filter change): 5.0 liters (5.3 qt).
Engine Oil Capacity (without filter change): 4.5 liters (4.8 qt).
Engine Oil Specification: 10W-30 or 20W-50, API SF/SG or higher.
Oil Change Interval: 5,000 km (3,100 miles) or 6 months (severe duty).
Oil Change Interval: 10,000 km (6,200 miles) for normal duty.
Coolant Capacity: Approximately 6.0-7.0 liters (6.3-7.4 qt).
Coolant Specification: Ethylene glycol-based, phosphate-inhibited.
Coolant Change Interval: 40,000 km (25,000 miles) or 24 months.
Timing Chain: Inspect chain and tensioner every 150,000 km (93,000
miles).
Valve Clearance (cold, intake): 0.15 mm (0.0059 in).
Valve Clearance (cold, exhaust): 0.25 mm (0.0098 in).
Valve Clearance Adjustment Interval: Every 20,000 km (12,500 miles).
Spark Plug Type: NGK BPR6ES or equivalent.
Spark Plug Gap: 0.7-0.8 mm (0.028-0.031 in).
Spark Plug Replacement Interval: 20,000 km (12,500 miles).
Distributor Cap and Rotor Replacement Interval: 40,000 km (25,000
miles).
Drive Belt Tension: Deflection of 10-12 mm (0.39-0.47 in) under 10 kg
(22 lb) force.
Fuel Filter Replacement Interval: 30,000 km (18,750 miles).
Air Filter Replacement Interval: 20,000 km (12,500 miles).
Idle Speed (manual transmission): 800 ± 50 rpm.
Idle Speed (automatic transmission, in drive): 750 ± 50 rpm.
Cylinder Head Bolts (Stage 1): 40 Nm (30 lb-ft)
Cylinder Head Bolts (Stage 2): 70 Nm (52 lb-ft)
Main Bearing Cap Bolts: 78 Nm (58 lb-ft)
Connecting Rod Cap Bolts: 48 Nm (35 lb-ft)
Camshaft Sprocket Bolts: 55 Nm (41 lb-ft)
Camshaft Cap Bolts: 20 Nm (15 lb-ft)
Crankshaft Pulley Bolt: 150 Nm (111 lb-ft)
Flywheel Bolts: 70 Nm (52 lb-ft)
Intake Manifold Bolts: 23 Nm (17 lb-ft)
Exhaust Manifold Nuts: 25 Nm (18 lb-ft)
Spark Plugs: 25 Nm (18 lb-ft)
Oil Pan Bolts: 10 Nm (7 lb-ft)
Water Pump Bolts: 12 Nm (9 lb-ft)
Oil Filter (spin-on): 15 Nm (11 lb-ft)
Engine Mount Brackets: 45 Nm (33 lb-ft)
Isuzu 117 Coupe (Giugiaro Edition, 1978-1981): The G200W was installed
in high-end variants of the 117 Coupe during its final production years.
This application featured Italian styling by Giorgetto Giugiaro, with
the engine producing 135 PS in a front-engine, rear-wheel-drive
configuration. The intake manifold was arranged in the "out right and
forward" design.
Isuzu Piazza (JR120/JR130, 1981-1985): The early Piazza - exported as
the Isuzu Impulse - received the G200W as its performance engine option.
This application used an "over the top" intake manifold design crossing
above the engine. Power output was 99 kW at 6200 rpm and 167 Nm at 5000
rpm. The engine was paired with a 5-speed manual transmission driving
the rear wheels.
Isuzu Gemini ZZ (ZZ/R, ZZ/E - swap application): While the G180W
(1.8-liter DOHC) was the standard engine for the Gemini ZZ, the G200W is
a popular performance upgrade due to matching engine mounts and
bellhousing patterns within the G-series family. Enthusiasts swap the
2.0-liter DOHC engine into Gemini chassis for increased displacement and
power output.
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