Subaru EA82 Specifications
| Engine Model: Subaru EA82 |
| Engine Type: 4-cycle 4-cylinder SOHC 8-valve liquid-cooled gasoline |
| Total Displacement: 108.7 cu.in (1.78 L) |
| Rated Engine Power: 84-135 Hp (63-101 kW) at 5600 rpm |
| Fuel System Type: Carburetor or Electronic fuel injection |
____________________________________________________________________________________
The Subaru EA82 is a 1.8-liter, liquid-cooled,
horizontally opposed four-cylinder (flat-four) engine produced from 1984 through
1994, serving as the successor to the EA81 and the primary powerplant for
Subaru’s “Old Generation” models before the introduction of the EJ series. The
EA82 represented a significant technological advancement within the EA family,
being the first Subaru engine to incorporate belt-driven single overhead
camshafts (SOHC) - one per cylinder bank - a configuration enabled by the
flat-four architecture.
The engine features aluminum cylinder blocks and aluminum cylinder heads, a
material selection that reduces overall mass while maintaining the inherent
balance advantages of the opposed-piston layout. The EA82 was offered with
multiple induction systems across its production life, including carburetion,
single-point fuel injection (SPFI), and multi-point fuel injection (MPFI), with
turbocharged variants available in certain markets.
The engine’s flat configuration results in a low center of gravity, contributing
to the handling characteristics that became a Subaru hallmark. Deployed across
the Leone, L-Series, Loyale, XT, and RX Turbo models, the EA82 accumulated a
reputation for durability despite known vulnerabilities related to head gasket
sealing, cylinder head cracking under overheating conditions, and hydraulic lash
adjuster noise.
The EA82 is a 4-stroke, horizontally opposed 4-cylinder, water-cooled gasoline
engine utilizing a single overhead camshaft (SOHC) per cylinder bank with two
valves per cylinder, totaling 8 valves. Total displacement is 1.781 Liters
(1,781 cc / 108.7 cu.in), derived from a bore of 92.0 mm (3.622 in) and a short
stroke of 67.0 mm (2.638 in). The oversquare bore-to-stroke ratio favors
higher-RPM power production while maintaining the compact width characteristic
of flat engines. The compression ratio varies by induction method and emissions
calibration, with naturally aspirated versions ranging from 9.0:1 to 9.5:1 and
turbocharged variants utilizing lower ratios between 7.7:1 and 8.0:1.
Power output varies significantly by configuration: naturally aspirated
carbureted versions produce 84-90 HP (63-67 kW) at 5,200-5,600 RPM; SPFI
versions produce 90-95 HP (67-71 kW); MPFI naturally aspirated versions produce
97-100 HP (72-75 kW); turbocharged MPFI versions produce 110-115 HP (82-86 kW)
in early variants and up to 135 HP (101 kW) in later intercooled configurations.
Torque output ranges from 138-149 Nm (102-110 lb-ft) at 3,200 RPM for naturally
aspirated engines to 172-196 Nm (127-145 lb-ft) for turbocharged variants. The
firing order is 1-3-2-4, with cylinder numbering following Subaru convention:
left bank (driver side) cylinders 1 and 3; right bank cylinders 2 and 4.
The cylinder block is constructed from aluminum alloy
using a horizontally opposed configuration with the cylinders arranged at 180
degrees. This flat layout results in a low overall height, a low center of
gravity, and inherent primary and secondary balance without the need for balance
shafts. The open-deck design incorporates cast-iron cylinder liners of the wet
type, with a finished bore diameter of 92.0 mm (3.622 in).
The crankshaft is forged from steel and is supported by five main bearings. The
connecting rods are forged steel with a full-floating wrist pin design. Pistons
are cast aluminum with the piston crown configuration varying by production era:
early engines (1984-1986) utilize flat-top pistons with open-chamber cylinder
heads; late engines (1987-1994) incorporate dished pistons matched to swirl-port
cylinder heads for improved emissions and combustion efficiency.
The crankcase is split horizontally at the crankshaft centerline, with the upper
crankcase integrated into the cylinder block casting and the lower crankcase
forming the oil pan mounting surface. Piston cooling is achieved through oil
splash rather than dedicated oil squirters.
Each cylinder head is manufactured from aluminum alloy
with a single overhead camshaft (SOHC) per bank operating two valves per
cylinder - one intake and one exhaust - through rocker arms. The camshafts are
driven by separate rubber timing belts from the crankshaft, with one belt routed
to each cylinder head. Valve diameters measure 40.0 mm (1.575 in) for intake and
34.0 mm (1.339 in) for exhaust.
The valvetrain utilizes hydraulic lash adjusters (HLAs) on most variants,
eliminating manual valve clearance adjustments; early carbureted versions may
employ mechanical adjusters requiring periodic maintenance. A known issue with
the hydraulic lash adjusters is the accumulation of air or contaminants,
resulting in a characteristic ticking noise often referred to as the “Ticking of
Death” (TOD). This condition is frequently caused by a failing oil pump drive
seal that allows air ingress into the lubrication system.
The cylinder head combustion chamber design evolved during production: early
open-chamber heads paired with flat-top pistons; late swirl-port heads with
dished pistons feature a raised quench area that promotes charge motion for
improved combustion stability and emissions performance. The cylinder heads are
susceptible to cracking between the intake and exhaust valves, particularly on
engines subjected to overheating events.
The EA82 was produced with three distinct fuel system
configurations across its production life. Carbureted versions utilize a
two-barrel downdraft carburetor manufactured by Hitachi, incorporating an
automatic choke, accelerator pump, and a variety of emission control devices.
Single-point fuel injection (SPFI) versions, introduced in 1987, employ a
throttle-body injection system with a single injector mounted above the throttle
plate, managed by a Subaru engine control unit.
Multi-point fuel injection (MPFI) versions, reserved for higher-output and
turbocharged applications, utilize four injectors mounted in the intake manifold
runners, each positioned to direct fuel toward the intake valves. The MPFI
system includes a fuel rail, a fuel pressure regulator with vacuum reference,
and an in-tank electric fuel pump.
Turbocharged MPFI variants incorporate an
air-to-air intercooler mounted above the engine, a knock sensor, and a
boost pressure control system with an internal wastegate. The intake
manifold is a two-piece aluminum casting with runners tuned to enhance
torque characteristics specific to each induction configuration.
The lubrication system is a full-flow, pressurized
design utilizing a gear-type oil pump mounted to the front of the crankshaft
within the timing cover. The oil pump draws oil from a steel oil pan through a
screened pickup tube and delivers it through a full-flow spin-on oil filter.
Total oil capacity ranges from 3.8 to 4.5 Liters (4.0-4.8 qt) depending on the
oil pan configuration and the presence of an oil cooler on turbocharged
variants.
A water-cooled oil cooler is integrated on turbocharged engines to stabilize oil
temperature under sustained high-load operation. The lubrication circuit
supplies oil to the crankshaft main bearings, connecting rod bearings, camshaft
bearings, hydraulic lash adjusters, and turbocharger bearing housing (where
equipped).
A critical component in the lubrication system is the oil pump drive seal;
failure of this seal allows air ingress, causing aeration of the oil and
resultant hydraulic lash adjuster noise and reduced oil pressure. Oil pressure
at operating temperature ranges from 1.5-3.5 bar (22-51 psi) across the normal
engine speed range. The recommended oil viscosity is 10W-40 or 20W-50 for older
engines, with a preference for formulations containing adequate zinc-based
anti-wear additives to protect the flat-tappet valvetrain on early variants.
The cooling system is a water-cooled, pressurized
design utilizing a belt-driven centrifugal water pump mounted to the front of
the engine block. Coolant circulates through the aluminum block and cylinder
heads, with a cross-flow aluminum radiator employed in all applications. The
thermostat is a wax-pellet unit with an opening temperature of 82°C (180°F) for
most applications. Total coolant capacity ranges from 6.0-7.5 Liters (6.3-7.9
qt) depending on vehicle platform and heater core configuration.
The cooling fan is an electric unit or a viscous clutch-driven fan depending on
the model and market. The flat engine configuration presents unique cooling
challenges, as the cylinder heads are positioned laterally, requiring careful
management of coolant flow to ensure uniform temperature distribution across
both banks. Head gasket failure is a known vulnerability, often manifesting as a
rear coolant leak that may be difficult to detect as coolant can migrate into
the oil pan or exhaust system without external visible leakage.
Timing System: The EA82 employs two separate rubber
timing belts, each driving one cylinder head camshaft from the crankshaft. Each
belt incorporates an automatic spring-loaded tensioner that maintains correct
belt tension. The engine is an interference design: failure of either timing
belt results in piston-to-valve contact, causing bent valves and requiring
cylinder head removal for repair. The timing belt replacement interval is
critical to engine longevity.
Ignition System: The ignition system varies by induction method. Carbureted and
SPFI versions utilize a distributor with mechanical and vacuum advance, driven
by the right camshaft. MPFI and turbocharged versions employ a distributor with
an integrated crank angle sensor that provides engine position data to the
engine control unit. The ignition coil is a single unit with high-tension leads
routed to the distributor. Spark plug gap is set at 1.0-1.1 mm (0.039-0.043 in)
for naturally aspirated engines and 0.8-0.9 mm (0.031-0.035 in) for turbocharged
variants.
Crankcase Ventilation: A closed positive crankcase ventilation (PCV) system
routes blow-by gases from the crankcase to the intake manifold through a PCV
valve. The system incorporates an oil separator within the crankcase to prevent
liquid oil from entering the intake tract.
Length measured from the front accessory drive face to
the transmission mounting flange is 670 mm (26.4 in). Width across the cylinder
heads and intake manifold assembly is 900 mm (35.4 in). Height from the oil pan
bottom surface to the top of the intake manifold is 500 mm (19.7 in).
The dry weight of the fully dressed engine -
including the intake manifold, exhaust manifolds, fuel system, ignition
system, and accessory drives - ranges from 82 to 100 kg (180-220 lb)
depending on the induction system and the presence of a turbocharger.
The timing belts are critical service items with a
mandatory replacement interval of 80,000 km (50,000 miles) under normal driving
conditions, with reduced intervals for severe-duty operation. The belts should
be replaced as a set with the tensioners. Engine oil and filter changes are
recommended at 5,000-7,500 km (3,000-4,500 miles) under normal driving
conditions.
Hydraulic lash adjusters (where equipped) do not require manual adjustment;
persistent ticking noise may indicate a failing oil pump drive seal, which
should be addressed to prevent oil pressure loss and further engine damage.
Valve clearance inspection and adjustment are required at 30,000 km (18,000
mile) intervals on engines with mechanical adjusters. Spark plug replacement is
recommended at 20,000 km (12,000 miles) for standard plugs. The fuel filter
should be replaced at 30,000 km (18,000 mile) intervals.
Coolant replacement is specified at 24 months or 40,000 km (25,000 miles). The
water pump should be inspected at each timing belt replacement and replaced
proactively due to the labor involved in accessing the component. Compression
pressure should be consistent across all four cylinders, with a standard value
of 1.2-1.4 MPa (174-203 psi) and a minimum service limit of 1.0 MPa (145 psi)
with maximum variation between cylinders of 0.1 MPa (15 psi).
Cylinder Head Bolts (Cold), Step 1: 30 Nm (22 lb-ft).
Cylinder Head Bolts (Cold), Step 2: 50 Nm (37 lb-ft).
Main Bearing Cap Bolts: 55-60 Nm (41-44 lb-ft).
Connecting Rod Cap Bolts: 45-50 Nm (33-37 lb-ft).
Crankshaft Damper Pulley Bolt: 150-170 Nm (111-125 lb-ft).
Camshaft Sprocket Bolts: 45-50 Nm (33-37 lb-ft).
Rocker Arm Shaft Bolts: 20-25 Nm (15-18 lb-ft).
Valve Cover Bolts: 5-7 Nm (44-62 lb-in).
Intake Manifold Bolts: 20-25 Nm (15-18 lb-ft).
Exhaust Manifold Nuts: 25-30 Nm (18-22 lb-ft).
Oil Pan Bolts: 8-10 Nm (71-89 lb-in).
Water Pump Bolts: 20-25 Nm (15-18 lb-ft).
Flywheel / Drive Plate Bolts: 60-70 Nm (44-52 lb-ft).
Timing Belt Tensioner Bolts: 20-25 Nm (15-18 lb-ft).
Engine Mount Bracket Bolts: 45-50 Nm (33-37 lb-ft).
The Subaru EA82 engine was deployed across a wide range
of Subaru models during its ten-year production run, serving as the primary
gasoline powerplant in international markets.
Subaru Leone / L-Series / GL / DL / Loyale: The EA82 powered the
third-generation Leone platform, marketed as the L-Series, GL, DL, and later as
the Loyale in North America. The engine was offered in carbureted, SPFI, and
MPFI configurations across sedan, coupe, wagon, and three-door body styles.
Subaru XT / Alcyone / Vortex: The wedge-shaped sports coupe received the EA82 in
both naturally aspirated and turbocharged MPFI configurations, with the
turbocharged version producing up to 135 HP (101 kW) in later intercooled
variants.
Subaru RX Turbo: The performance-oriented three-door coupe utilized the
turbocharged MPFI EA82, featuring a water-cooled turbocharger and, in later
variants, an air-to-air intercooler. The RX Turbo was offered with a five-speed
manual transmission and full-time four-wheel-drive.
Subaru Omega: The Japanese Domestic Market sedan and coupe variants utilized the
EA82 across their production run, with induction configurations tailored to
market-specific emissions and performance requirements.
Subaru Brat / Brumby (Late Models): The light utility vehicle received the EA82
in select markets as an upgrade from the EA81, though production continued with
the EA81 in most applications.
____________________________________________________________________________________
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Industrial Engines Technical Specifications |
| Outboard Engines Technical Specifications |
