Isuzu G200Z Specifications
| Engine Model: Isuzu G200Z |
| Engine Type: 4-stroke in-line 4-cylinder 8-valve SOHC liquid-cooled gasoline |
| Total Displacement: 119 cu.in (1.95 L) |
| Rated Engine Power: 79-118 Hp (58-88 kW) at 4800-5800 rpm |
| Fuel System Type: Carburetor |
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The Isuzu G200Z is a 2.0-liter inline-four
cylinder naturally aspirated petrol engine produced by Isuzu throughout
the 1980s and into the early 1990s. This engine belongs to the Isuzu
G-family and features a Single Overhead Camshaft (SOHC) design with two
valves per cylinder, distinguishing it from the performance-oriented
twin-cam G200W variant.
The G200Z served as a versatile workhorse powerplant for Isuzu, powering
a wide range of vehicles including pickup trucks such as the Isuzu P'up
and KB, SUVs including the early Isuzu Trooper and Bighorn, and
commercial vans such as the Isuzu Fargo. The robust cast iron
construction combined with a timing chain drive system provided high
durability suitable for commercial applications.
The G200Z represents a practical engineering approach focused on
reliability and serviceability rather than high performance. With a
displacement of 1,949 cc derived from an 87.0 mm bore and 82.0 mm
stroke, the engine produces a bore/stroke ratio of 1.06:1, a slightly
oversquare configuration favoring responsiveness. The compression ratio
stands at 8.8:1, permitting operation on lower-octane fuels without
knock. The engine employs a timing chain rather than a belt, providing
extended service life and eliminating the risk of catastrophic valve
damage from belt failure.
This remains critical as the G200Z is an interference design where
valve-to-piston contact occurs if timing components fail. The cross-flow
aluminum cylinder head with a cast iron block creates a durable
composite structure. Power output varies by application and tuning,
ranging from 58 kW (79 hp) in commercial versions to 88 kW (118 hp) in
passenger car configurations. Torque delivery peaks at a relatively low
3,000-4,000 rpm, matching the engine's utilitarian character.
Engine Type: 4-stroke, inline, naturally aspirated, petrol
Engine Code: G200Z
Configuration: Vertical inline, liquid-cooled, 4-cylinder
Displacement: 1,949 cc (119.0 cu.in)
Bore: 87.0 mm (3.425 in)
Stroke: 82.0 mm (3.228 in)
Bore/Stroke Ratio: 1.06:1 (slightly oversquare)
Compression Ratio: 8.8:1
Valvetrain: SOHC, 8 valves (2 per cylinder), timing chain drive
Firing Order: 1-3-4-2
Power (Commercial/pickup): 58-64 kW (79-86 hp) at 4,600-4,800 rpm
Power (Passenger car): 88 kW (118 hp) at 5,800 rpm
Torque Output: Ranges 146-162 Nm (108-119 lb-ft):
Peak torque achieved at 3,000-4,000 rpm depending on tuning
Ignition Timing: 6° BTDC at 800-900 rpm (vacuum line disconnected)
Spark Plug Gap: 0.7-0.8 mm (0.028-0.031 in)
Idle Speed: 800-900 rpm
The cylinder block is constructed from cast iron, providing structural
rigidity and wear resistance suited for commercial vehicle duty cycles.
The crankshaft is supported by five main bearings, reducing flex and
extending bearing life under sustained loads. The block incorporates a
timing chain housing at the front, with the camshaft drive chain running
directly from the crankshaft sprocket to the camshaft sprocket.
A hydraulic chain tensioner, which relies on engine oil pressure,
maintains proper chain tension during operation. The cylinder bores are
machined directly into the block without replaceable liners. The
crankcase design includes a full-depth skirt for added rigidity. Engine
mounting points are provisioned for longitudinal installation in
rear-wheel drive and four-wheel drive chassis configurations.
The cylinder head is manufactured from cast aluminum alloy utilizing a
cross-flow design with the intake manifold on one side and exhaust
manifold on the other. The SOHC arrangement employs a single camshaft
operating eight valves through rocker arms. Hydraulic lash adjusters are
not used; manual valve clearance adjustment is required.
The combustion chambers are of a wedge design with spark plugs
positioned between the valves. The intake ports are sized for naturally
aspirated operation. The exhaust manifold mounting flange accommodates a
single outlet. The aluminum head requires careful thermal management as
overheating can cause warping. Valve Clearances (engine hot): Intake:
0.15 mm (0.006 in). Exhaust: 0.25 mm (0.010 in).
The fuel system employs a downdraft carburetor as standard equipment,
consistent with the engine's 1980s design era. The carburetor includes
an automatic choke for cold start enrichment. A mechanical fuel pump,
mounted on the cylinder block and actuated by an eccentric lobe on the
camshaft, draws fuel from the tank and supplies the carburetor float
chamber.
A fuel filter is positioned between the fuel pump and carburetor. The
intake manifold is cast aluminum with integrated water jacket heating
passages to improve fuel vaporization during warm-up. The mechanical
fuel pump design permits engine operation without electrical power once
started, a feature suited for commercial and off-road applications.
The lubrication system is a pressurized, full-flow filtered system with
a gear-type oil pump. The oil pump, mounted on the front of the
crankshaft, draws oil from the sump through a screened pickup tube. Oil
passes through a full-flow spin-on filter mounted on the cylinder block.
Pressurized oil routes to the five main bearings, connecting rod
bearings, camshaft bearings, and rocker arm assembly. The hydraulic
timing chain tensioner receives oil pressure through a dedicated passage
in the cylinder block. A pressure relief valve maintains system pressure
within specification.
Oil Pressure at Operating Speed: 345-414 kPa (50-60 psi)
Oil Pressure at Idle: 69-138 kPa (10-20 psi)
Oil Capacity (with filter): 4.0-4.5 L (4.2-4.8 qt)
Recommended Oil: SAE 10W-30 or 10W-40, API SG or higher
The cooling system is pressurized and liquid-cooled, utilizing a
belt-driven centrifugal water pump. Coolant circulates from the radiator
bottom tank through the water pump, into the cylinder block water
jacket, upward through the cylinder head, and back to the radiator top
tank.
A wax-type thermostat in the coolant outlet housing maintains operating
temperature. A belt-driven fan mounted to the water pump pulley draws
air through the radiator core. The aluminum cylinder head expands at a
different rate than the cast iron block, requiring proper warm-up
procedures and coolant maintenance to prevent head gasket failure.
Coolant Capacity (engine only): 5.0-6.0 L (5.3-6.3 qt)
Thermostat Opening Temperature: 82-88°C (180-190°F)
Coolant Type: Ethylene glycol-based with corrosion inhibitors
Ignition System: Electronic distributor-type ignition with vacuum and
centrifugal advance mechanisms. The distributor housing incorporates a
breaker points assembly on earlier models or electronic trigger on later
versions. A single ignition coil supplies high voltage to the
distributor rotor.
Electrical System: 12-volt with negative ground (industry standard for
this era).
Starting System: Electric starter with solenoid engagement, mounted to
the transmission bellhousing.
Charging System: Belt-driven alternator with internal or external
voltage regulator depending on model year.
Intake System: Single carburetor with dry-type paper element air
cleaner.
Exhaust System: Cast iron exhaust manifold with single outlet pipe.
Overall Length: 650 mm (25.6 in)
Overall Width: 600 mm (23.6 in)
Overall Height: 700 mm (27.6 in)
Dry Weight: 135-150 kg (298-331 lb) with standard equipment
Engine Oil Capacity (with filter): 4.0-4.5 L (4.2-4.8 qt).
Engine Oil Type: SAE 10W-30 or 10W-40, API SG or higher.
Coolant Capacity: Varies by configuration; engine-only 5.0-6.0 L
(5.3-6.3 qt).
Coolant Type: Ethylene glycol-based anti-freeze with corrosion
inhibitors.
Oil Change Interval: 3,000-5,000 miles (4,800-8,000 km) or 6 months.
Valve Clearance Check Interval: 15,000 miles (24,000 km).
Valve Clearance (hot, intake): 0.15 mm (0.006 in).
Valve Clearance (hot, exhaust): 0.25 mm (0.010 in).
Spark Plug Gap: 0.7-0.8 mm (0.028-0.031 in).
Ignition Timing: 6° BTDC at 800-900 rpm with vacuum line disconnected.
Timing Chain Inspection: Regular oil changes essential for hydraulic
tensioner.
Cylinder Head Bolts, Step 1: 29 Nm (21 lb-ft).
Cylinder Head Bolts, Step 2: 69 Nm (51 lb-ft).
Cylinder Head Bolts, Step 3: 98 Nm (72 lb-ft) final.
Connecting Rod Cap Nuts: 37-43 Nm (27-32 lb-ft).
Main Bearing Cap Bolts: 70-80 Nm (52-59 lb-ft).
Flywheel Bolts: 50-60 Nm (37-44 lb-ft).
Crankshaft Pulley Bolt: 120-140 Nm (89-103 lb-ft).
Camshaft Sprocket Bolt: 50-60 Nm (37-44 lb-ft).
Rocker Arm Shaft Bracket Bolts: 18-22 Nm (13-16 lb-ft).
Intake Manifold Nuts/Bolts: 18-22 Nm (13-16 lb-ft).
Exhaust Manifold Nuts: 18-22 Nm (13-16 lb-ft).
Spark Plugs: 15-20 Nm (11-15 lb-ft).
Oil Pan Drain Plug: 35-40 Nm (26-30 lb-ft).
The Isuzu G200Z engine was installed in the following vehicles,
primarily during the 1980s.
Isuzu Trooper / Bighorn (UBS13): Early models 1981-1985.
Isuzu P'up / LUV / KB (KB28, KB48): Pickup trucks 1985-1988, 79 hp (58
kW).
Isuzu Piazza / Impulse (1983-1987): 88 kW (118 hp) at 5,800 rpm.
Isuzu 117 Coupe (PA96): Final generation 1978-1981.
Isuzu Fargo (WFR): Van application.
Holden Jackaroo: Australian market version of early Trooper.
Isuzu Faster: Select export markets.
Isuzu Rodeo (early configurations): Select markets.
Hindustan Ambassador / Contessa: Later 2.0 L petrol versions produced in
India.
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