Honda D16A6 Specifications
| Engine Model: Honda D16A6 |
| Engine Type: 4-cycle inline 4-cylinder SOHC 16-valve liquid-cooled gasoline |
| Total Displacement: 97 cu.in (1.59 L) |
| Rated Engine Power: 108-113 Hp (81-84 kW) at 6000 rpm |
| Fuel System Type: Multi-point electronic fuel-injection (PGM-FI) |
____________________________________________________________________________________
The Honda D16A6 is a 1.6-liter inline
four-cylinder gasoline engine developed during the late 1980s as part of
the Honda D-series architecture and was widely used in the Honda Civic
and CRX models. Designed to deliver a balance of strong mid-range
response, moderate fuel economy, and high mechanical reliability, the
D16A6 became a well-regarded engine among enthusiasts and daily drivers
alike.
It features an aluminum SOHC cylinder head,
cast-iron block, multi-point fuel injection, and a robust rotating
assembly that allows smooth operation up to its factory redline. The
D16A6 earned a reputation for being durable, tunable, and simple to
service while providing consistent performance characteristics typical
of Honda’s engineering philosophy of the period.
The Honda D16A6 is a four-stroke, inline four-cylinder engine displacing
1,590 cc (97.0 cubic inches). Bore is 75.0 mm (2.95 inches), and stroke
is 90.0 mm (3.54 inches), producing an undersquare configuration that
promotes torque production in the mid-range. Factory compression ratio
is approximately 9.5:1.
Power output is typically 108 horsepower (81
kW, 106–108 bhp) at around 6,000 rpm. Peak torque is about 136 Nm (100
lb-ft) delivered near 4,800 rpm. Idle speed is calibrated at 700 ± 50
rpm. Redline is generally around 6,800 rpm, with ECU-imposed fuel cutoff
slightly above that threshold.
The firing order is 1-3-4-2. The cast-iron block provides long-term
durability, while the aluminum SOHC cylinder head enhances heat
dissipation and reduces weight. The valvetrain consists of a single
overhead camshaft operating four valves per cylinder through rocker
arms. Valve lash is manually adjustable.
The crankshaft is supported by five main bearings for stability at high
rpm. Pistons are cast aluminum alloy with fully floating wrist pins, and
connecting rods are forged steel. The engine uses a toothed rubber
timing belt to drive the camshaft and water pump. Replacement intervals
fall between 90,000 and 100,000 km (55,000–62,000 miles).
Fuel delivery is handled by Honda’s PGM-FI multi-point fuel injection
system. Fuel is supplied by an electric in-tank pump to the rail at a
regulated pressure of approximately 36–42 psi (250–290 kPa).
Solenoid-operated injectors meter fuel based on ECU calculations.
The ECU receives input from the throttle position sensor, manifold
absolute pressure sensor, intake-air temperature sensor, coolant
temperature sensor, oxygen sensor, and crank-angle sensor in the
distributor. These parameters allow the ECU to maintain efficient
combustion during idle, acceleration, and cruising. Recommended fuel is
unleaded gasoline of at least 87 AKI (91 RON).
The lubrication system is a full-pressure wet-sump type with a
crankshaft-driven trochoid oil pump. Oil is drawn through a pickup
screen and routed through a full-flow spin-on filter before reaching the
main oil gallery.
Oil capacity with filter is approximately 3.7 to 3.9 liters (3.9 to 4.1
US quarts). Recommended viscosity is SAE 5W-30 or 10W-30 meeting API SJ
or higher. Normal oil pressure is expected to be at least 10 psi at idle
and between 50 and 70 psi at cruising rpm. The PCV system provides
crankcase ventilation and emissions control.
Cooling is provided by a closed-loop liquid cooling system. A
belt-driven centrifugal water pump circulates coolant through the block,
head, radiator, and heater core. Thermostat begins opening at about 82°C
(180°F) and is fully open near 95°C (203°F). System capacity is roughly
5.5 liters (5.8 US quarts).
Radiator cap pressure is typically rated at 13–16 psi (90–110 kPa). A
50/50 mixture of ethylene glycol and distilled water is recommended.
Coolant replacement is required every 40,000 km (25,000 miles) or two
years.
| Intake and Exhaust Systems |
The induction system includes an air cleaner with a replaceable paper
filter, intake resonator, and aluminum intake manifold. The throttle
body is cable-controlled and houses base idle components.
The exhaust system is equipped with a cast-steel exhaust manifold
feeding a catalytic converter positioned close to the engine to reduce
emissions during cold start. Oxygen sensor feedback allows for
closed-loop operation. Downstream piping includes a resonator and
muffler tuned for noise reduction.
| Ignition and Electrical System |
The D16A6 ignition system uses an electronic distributor containing a
built-in ignition coil, igniter module, and sensors for cam and crank
reference. Ignition timing is ECU-controlled and takes engine load,
speed, and knock feedback into account. The system employs conventional
spark plug wires to deliver high voltage.
Recommended spark plugs are NGK or Denso equivalents with a gap of 1.0
millimeter (0.039 inch). Standard copper plugs typically require
replacement at 20,000–30,000 km (12,000–18,000 miles), while platinum
variants may last up to 60,000 km (37,000 miles).
The electrical system operates at 12 volts. The alternator typically
provides 70–80 amperes. The starter motor uses a reduction-gear design
drawing from a 12-volt battery rated around 40–60 amp-hours. Engine
grounding ensures correct sensor operation and ECU stability.
Sensors include MAP, TPS, IAT, ECT, O2 sensor, and distributor-based
crank/cam reference triggers. Wiring looms are insulated against heat
and vibration.
Dimensions of the D16A6 engine assembly include: length 600 to 630 mm
(23.6 to 24.8 inches), width 550 to 600 mm (21.7 to 23.6 inches), and
height approximately 650 to 700 mm (25.6 to 27.6 inches). Dry weight
generally ranges from 115 to 135 kg (254 to 298 lbs), depending on
accessories and emissions equipment.
Routine maintenance for the D16A6 includes:
Oil and filter every 10,000 km (6,000 miles).
Air filter every 20,000 km (12,000 miles).
Spark plug replacement every 20,000–30,000 km (standard) or up to 60,000
km (platinum).
Fuel filter replacement every 40,000 km (25,000 miles).
Valve clearance checks every 40,000 to 50,000 km.
Timing belt replacement every 90,000 to 100,000 km (55,000 to 62,000
miles).
Coolant replacement every 40,000 km or two years.
Compression pressure for a healthy engine is typically between 180 and
200 psi (1,240 to 1,380 kPa), with a maximum allowable variation of 10
percent across cylinders.
Cylinder head bolts: 70 to 75 Nm (51 to 55 lb-ft).
Main bearing cap bolts: 50 to 60 Nm (38 to 43 lb-ft).
Connecting rod bolts: 35 to 40 Nm (28 to 33 lb-ft).
Camshaft bearing cap bolts: 11 to 13 Nm (9 to 10 lb-ft).
Flywheel bolts: 85 to 95 Nm (63 to 70 lb-ft).
Crankshaft pulley bolt: 130 to 140 Nm (96 to 103 lb-ft).
Intake manifold bolts: 20 to 22 Nm (16 to 18 lb-ft).
Exhaust manifold nuts: 28 to 30 Nm (21 to 24 lb-ft).
Spark plugs: 18 Nm (13 lb-ft).
Oil drain plug: 35 Nm (26 lb-ft).
The Honda D16A6 engine was installed primarily in late-1980s and
early-1990s Honda Civic and CRX models. These include hatchbacks,
sedans, and compact coupes designed for efficient commuting and sporting
driving characteristics. The engine is widely appreciated in the
automotive enthusiast community for its durability, ease of
modification, and compatibility with other Honda components. It remains
a popular platform for restoration and light performance upgrades.
____________________________________________________________________________________
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Industrial Engines Technical Specifications |
| Outboard Engines Technical Specifications |
