Honda A20A3 & A20A4

Honda A20A4The Honda A20A3/A20A4 is a 2.0 l (1,955 cc, 119.3 cu-in) straight-4, four-stroke cycle gasoline engine from Honda A20A-family. The Honda A20A3 and A20A4 motors was produced from 1984 through 1989.

Both engines have SOHC (single overhead camshaft) design with 12 valves (3 per cylinder). The engines used a cast-iron cylinder block with a five bearing supported system and aluminum cylinder head. The engines are equipped with Honda PGM-FI fuel injection system.

Basically, this is the same motor but the A20A4 gives a higher power output because of not having emissions components and offered for Europen market.

An 82.7 mm (3.26 in) cylinder bore and 91.0 mm (3.58 in) piston stroke give the motor a total of 1,955 cc of displacement. Compression ratio ratings are various: 8.8:1, 8.9:1, 9.4:1.

The engines produced:

  • 1984-1987: 99 PS (73 KW; 98 HP) at 5,500 rpm of horsepower and 138 Nm (14.1 kg·m; 101.8 ft·lb) at 4,500 rpm of torque
  • 1988-1989: 121 PS (89 KW; 120 HP) at 5,500 rpm of horsepower and 165 Nm (16.8 kg·m; 121.8 ft·lb) at 4,500 rpm of torque

The breakdown of the engine code is as follows:

  • A – Engine Family
  • 20 – 2.0 Liter Displacement
  • A3, A4 – Engine version

General information

Engine Specifications
Engine codeA20A3 / A20A4
LayoutFour stroke, Inline-4 (Straight-4)
Fuel typeGasoline
Displacement2.0 L, 1,955 cm3 (119.3 cu in)
Fuel systemElectronic fuel injection system
Power adderNone
Max. horsepower 99 PS (73 KW; 98 HP) at 5,500 rpm
121 PS (89 KW; 120 HP) at 5,500 rpm
Max. torque 138 Nm (14.1 kg·m; 101.8 ft·lb) at 4,500 rpm
165 Nm (16.8 kg·m; 121.8 ft·lb) at 4,500 rpm
Firing order1-3-4-2
Dimensions (L x H x W):
Weight123 kg (271.2 lbs)

Cylinder block

Cylinder block
Cylinder block alloyCast iron
Compression ratio:8.8:1, 8.9:1, 9.4:1
Cylinder bore:82.7 mm (3.26 in)
Piston stroke:91.0 mm (3.58 in)
Number of piston rings (compression / oil):2 / 1
Number of main bearings:5
Cylinder inner diameter (standard):82.70-82.71 mm (3.2559-3.2563) in)
Piston skirt diameter (standard):82.67-82.68 mm (3.2547-3.2551 in)
Piston ring end gap:Top0.20-0.35 mm (0.008-0.014 in)
Second0.25-0.37 mm (0.010-0.015 in)
Oil0.20-0.70 mm (0.008-0.020 in)
Crankshaft journal diameter:49.970-49.994 mm (1.9673-1.9683 in)
Crankpin diameter:44.976-45.000 mm (1.7707-1.7717 in)
Crankshaft center distance:45.5 mm (1.7913 in)

Main bearing beam bolts tightening procedure and torque specs:

  • 68 Nm; 6.8 kg·m; 49 ft·lb in two-three stages

After securing bearing cap bolts, make sure crankshaft turns smoothly by hand.

Connecting rod bearing nut

  • 32 Nm; 3.2 kg·m; 23 ft·lb

Flywheel (M/T) or Drive plate (A/T) fixing bolts

  • Flywheel (M/T): 105 Nm; 10.5 kg·m; 76 ft·lb
  • Drive plate (A/T): 75 Nm; 7.5 kg·m; 54 ft·lb

Cylinder head

The cylinder head is made of aluminum alloy. The valve system has a pivot type rocker arm that is activated directly by the cam mechanism. The camshaft is driven with a double timing chain from the crankshaft. The engines use three valves per cylinder (two intake valves and single exhaust valve) and the dual type valve springs for exhaust valves.

Cylinder head
Valve Arrangement:SOHC, chain drive
Valves:12 (3 valves per cylinder)
Cylinder head height:90 mm (3.54 in)
Valve stem diameter:INTAKE6.58-6.59 mm (0.2591-0.2594 in)
EXHAUST6.94-6.95 mm (0.2732-0.2736 in)
Valve spring free length:INTAKE49.2 mm (1.94 in)
EXHAUST Outer: 39.8 mm (1.57 in)
Inner: 49.8 mm (1.96 in)
Cam lobe height:INTAKE A: 38.853 mm (1.5296 in)
B: 38.604 mm (1.5198 in)
EXHAUST38.796 mm (1.5274 in)

Head tightening procedure and torque specs:

  • Step 1: 30 Nm; 3.0 kg·m; 22 ft·lb
  • Step 2: 68 Nm; 7.0 kg·m; 49 ft·lb

Camshaft sprocket bolt

  • 38 Nm; 3.8 kg·m; 27 ft·lb

Maintenance data

Valve clearance
Intake valve0.12-0.17 mm (0.005-0.007 in)
Exhaust valve0.25-0.30 mm (0.010-0.012 in)
Compression pressure
Standard12.5 kg/cm2 (178 psi) / 300 rpm
Minimun10.5 kg/cm2 (149 psi) / 300 rpm
Differential limit between cylinders2.0 kg/cm2 (28 psi) / 300 rpm
Oil system
Oil consumption , L/1000 km (qt. per miles)up to 0.5 (1 qt. per 1200 miles)
Recommended engine oil10W-30
Oil type APISF or SG
Engine oil capacity (Refill capacity) With oil filter: 3.5 l (3.7 US qt., 3.1 Imp. qt.)
Without oil filter: 3.0 l (3.2 US qt., 2.6 Imp. qt.)
Oil change interval, km (miles)12,000 (7,500)
Oil pressure3.8-4.6 kg/cm2 (54-65 psi) at 3,000 rpm
Ignition system
Spark plug BPR-6ES-11 (NGK), W20EPR-U11 (DENSO)
Spark plug gap1.0-1.1 mm (0.039-0.043 in)
Spark plug tightening torque18 Nm; 1.8 kg·m; 13 ft·lb

Vehicle applications

ModelYears Produced
Honda Prelude1984-1987
Honda Accord1986-1989
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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  1. I think you have the wrong horsepower rating (98 HP) for the 1984 – 1987 engine. You may have used the horsepower of the engine with a carburetor. I have seen a power of 110 HP for the fuel injected engine (A20A3) before 1988. I believe the intake and exhaust manifold were changed in 1988 to add 10 HP.

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