The Honda B20A engine series, known as the B20A and B21A was an inline four-cylinder engine family from
Honda
is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan.
Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
introduced in 1985 in the
second-generation Honda Prelude. Also available in the contemporary
third-generation Honda Accord in the
Japanese domestic market
Japanese domestic market (JDM) refers to Japan's home market for vehicles and vehicle parts.
There is a common misconception that any Japanese branded car is JDM; however, this is not true. Only a vehicle made in Japan specifically to be sold i ...
, along with the Accord-derived Vigor, the B20A was Honda's second line of multivalve DOHC inline four-cylinder engines behind the "ZC" twin-cam variant of the ordinarily SOHC D-series, focused towards performance and displacing 2.0 to 2.1 litres.
The
third-generation Prelude was exclusively powered by the B20A engine family and production of the B20A engine family ended with the conclusion of the production of the third-generation Prelude in 1991.
History
The B20A would be succeeded by the
Honda B engine
The B-series are a family of inline four-cylinder DOHC automotive engines introduced by Honda in 1988. Sold concurrently with the D-series which were primarily SOHC engines designed for more economical applications, the B-series were a performan ...
family. Although sharing similar nomenclature and some design elements, the earlier B20A substantially differs from the later B-series in architecture enough to be considered two different engine families and is also not to be confused with the B20B, a 2.0 liter DOHC engine introduced alongside the
Honda CR-V
The Honda CR-V (also sold as the Honda Breeze in China since 2019) is a compact crossover SUV manufactured by the Japanese automaker Honda since 1995. The early model was built using the same platform as the Civic.
Honda began producing the CR ...
in 1994.
There were two versions of the B20A:
* The first generation of B20A engines was available in the 86–87 Prelude 2.0SI in Japan and in Europe, the 86–89
Honda Vigor
The is a premium sedan that was derived from the Honda Accord. It was sold in Japan through the ''Honda Verno'' dealer network from 1981 until 1995, and sold in North America from June 1991 (model year 1992) until 1994 as the Acura Vigor. Early ...
and Accord. It leaned towards the front of the car just like the A20A engine found in the same cars. This B20A produces and torque in Japan. In Europe this is called B20A1, producing and 127 lb.ft (172 Nm).
** There was also a similar engine named B18A for the 86–89 Accords. It was a de-stroked B20A powered by two sidedraft Keihin carbs.
* The second generation of B20A was found in the 88–91 Prelude. The 88–91 Prelude B20A and B21A blocks are cast so they lie at an 18-degree angle leaning towards the firewall. This was done to please the exterior specifications for the 1988–1991 3rd Generation Prelude due to its ultra-low hoodline which Honda dubs the "engineless design" and also for handling reasons; placing the engine at an angle gives it a lower center of gravity (similar to straight 6 designs in older BMW's).
The B20A, B20A3, and B20A5 engines consisted of closed-deck aluminum blocks with thicker-than-average iron
sleeves
A sleeve ( ang, slīef, a word allied to '' slip'', cf. Dutch ) is the part of a garment that covers the arm, or through which the arm passes or slips.
The sleeve is a characteristic of fashion seen in almost every country and time period, ac ...
whereas the B21A1 had
FRM (fiber reinforced metal) cylinder liners.
The B21A1 was basically a re-worked B20A5 with an increase in bore to . The external block dimensions had to stay identical (although there was increased external strengthening and webbing on the B21) to the B20A5 block so Honda called upon
Saffil to create a thin but strong cylinder liner using
FRM (fiber reinforced metal) which consisted of a carbon fiber matrix, aluminum alloy, and aluminum oxide to make a very strong cylinder
sleeve
A sleeve ( ang, slīef, a word allied to ''slip'', cf. Dutch ) is the part of a garment that covers the arm, or through which the arm passes or slips.
The sleeve is a characteristic of fashion seen in almost every country and time period, acro ...
. The sleeve is so strong, in fact, that it wears out the piston rings, causing low compression numbers, severe smoking, and high oil usage. It is possible in many situations to merely replace the worn rings in order to revive the motor's former output. Many machine shops will not attempt to re-hone or re-bore the FRM sleeves, as this type of sleeve will de-laminate during machining operations.
B20A, B20A1
(16-Valve, 4 Cylinder, DOHC, PGM-FI)
* "Honda" logo in center of valve cover – Filler cap on left side of cover.
* Found in:
** Serial numbers 1000001~, 1500001~ and 1550001~
*** 1985–1987.03
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
Non-U.S.
*** 1985.06–1987.04
Honda Accord
The , also known as the in Japan and China for certain generations, is a series of cars manufactured by Honda since 1976, best known for its four-door sedan variant, which has been one of the best-selling cars in the United States since 1989. ...
Non-U.S.
*** 1985.06–1987.04
Honda Vigor
The is a premium sedan that was derived from the Honda Accord. It was sold in Japan through the ''Honda Verno'' dealer network from 1981 until 1995, and sold in North America from June 1991 (model year 1992) until 1994 as the Acura Vigor. Early ...
Non-U.S.
** Serial numbers 1600001~ and 1640001~
*** 1987.05–1989.08
Honda Accord
The , also known as the in Japan and China for certain generations, is a series of cars manufactured by Honda since 1976, best known for its four-door sedan variant, which has been one of the best-selling cars in the United States since 1989. ...
Non-U.S.
*** 1987.05–1989.08
Honda Vigor
The is a premium sedan that was derived from the Honda Accord. It was sold in Japan through the ''Honda Verno'' dealer network from 1981 until 1995, and sold in North America from June 1991 (model year 1992) until 1994 as the Acura Vigor. Early ...
Non-U.S.
* Displacement: 1958 cc
** bore:
** stroke:
* Compression: 9.4:1
* Power:
** (JDM GOLD TOP B20A 1985.06–1987.04) at 6300 rpm & 137 lb.ft (186 N·m) at 5000 rpm (!JIS Gross data), using PH3 ECU
** (JDM BLACKTOP B20A 1987.05–1989.08) at 6200 rpm & 127 lb.ft (173 N·m) at 4000 rpm (!JIS Net data with new dual stage intake manifold), using PH3 ECU
** (EDM, B20A1 Gold Top) at 6000 rpm & 127 lb.ft (172 N·m) at 4000 rpm, using PJ5 (602,603,752), PJ7, PH3 ECU w vac. advance
* Transmission: B2K5(86–87), F2K5(88–89)
The B20A installed in 1988–1991 Preludes have the following specifications:
(16-Valve, 4 Cylinder, DOHC, PGM-FI)
* Found in:
** 1988–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
Non-U.S.
* Power: at 6000 rpm
* Torque: 128tq at 4500 rpm
* Compression ratio: 9.4:1
B20A2
(16-Valve, 4 Cylinder, DOHC, PGM-FI)
* Found in:
** 1987–1989
Honda Accord (CA5), Europe
* Power: at 6000 rpm
B20A3
(12-valve, SOHC, dual side-draft carburetors)
* Found in:
** 1988–1990
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
''2.0 S''
* Power: at 5800 rpm (MT) with catalytic converter, at 5800 rpm without catalytic converter
* Torque: at 4000 rpm
* It was PGM-CARB microprocessor controlled (pk-1)
B20A4
(12-Valve, SOHC, dual side-draft carburetors)
* Found in: 1988–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
Non-U.S.
* Fuel system: 2 carburetors
* Displacement (cm3): 1958
* Bore x Stroke (mm): 81 x 95
* Compression ration: 9.2:1
* Maximum power: 114 hp at 5800 rpm
* Maximum torque: 116 ft lb at 4500 rpm
* Catalytic converter: no
* ECU: no
B20A5
(16-valve, DOHC, PGM-FI)
* Found in:
** 1988–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
''2.0Si''
* Power: at 6200 rpm
* Torque: at 4000 rpm
* Engine cc: 1958.14
* Cylinder cc: 489.535
* Deck cc: 13.885
* Head cc: 47.3
* Compression Ratio: 9.0:1
B20A6
(16-Valve, DOHC, PGM-FI)
* Found in:
** 1988–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
Non-U.S. and Australian Domestic Market
at 6000 rpm
174 Nm at 4500 rpm
KY model is one of them
B20A7
(16-Valve, DOHC, PGM-FI)
* Found in:
** 1988–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
Non-U.S. UK, France, Holland, Norway, South Africa, New Zealand
* Power at 6000 rpm
* Torque 132tq (180 Nm) at 5500rpm
* Compression ratio 10.5:1
* Bore 81 mm
* Stroke 95 mm
* Engine capacity 1958 cm3 or 119.5 cu-in
B20A8
(16-Valve, DOHC, PGM-FI)
* Found in:
** 1988–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
Non-U.S. Russian, Swedish Domestic Market
** 1988–1989
Honda Accord
The , also known as the in Japan and China for certain generations, is a series of cars manufactured by Honda since 1976, best known for its four-door sedan variant, which has been one of the best-selling cars in the United States since 1989. ...
Non-U.S.
* Power at 6000 rpm
B20A9
(16-Valve, 4Cylinder, DOHC, PGM-FI)
* Found in:
** 1990–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
Non-U.S. Finland, Germany, Norway, Netherlands, Russia, Argentina
* Power at 6000 rpm
* Torque 129tq (175 Nm) at 4500 rpm
* Cylinder cc: 489.535
* Deck cc: 13.885
* Head cc: 47.3
* Compression ratio 9,3:1
File:B20a9stamp.jpg, B20A9 engine code stamp
----
B21A
(16-valve, DOHC, PGM-FI)
* Found in:
** 1990–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
''Si States''
* Very rare, it was only produced for the "Si States" models in Japan
* Power:
* Torque: 186 N·m (137 lb·ft)
* Compression Ratio: 9.4:1
[look at ]
engine using a pk-3 honda ECU
File:B21a.jpg, B21a
File:B21Astamp.jpg, B21A engine code stamp
----
B21A1
(16-valve, DOHC, PGM-FI)
* Found in:
** 1990–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
SI USDM
** 1990–1991
Honda Prelude
The Honda Prelude is a car produced by Japanese car manufacturer Honda from 1978 until 2001. The two-door coupe was loosely derived from the Honda Accord, and spanned five generations. The Prelude was used by Honda to introduce the Japanese Honda r ...
SR Canadian Market
* Power: at 5800 rpm
* Torque: at 5000 rpm
* Engine cc: 2056.03
* Bore 83 mm
* Stroke 95 mm
* Cylinder cc: 514.0075
* Deck cc: 10.191
* Head cc: 51.0
* Compression Ratio: 9.4:1
File:B21a1front.JPG, Block casting – FRONT
File:B21a1rear.JPG, Block casting – REAR
See also
*
List of Honda engines
This is a list of internal combustion engines models manufactured by the Honda Motor Company.
Automotive
Inline 2-cylinder
* EH:1977–1988 Acty:1985–1988 Today
Inline 3-cylinder
* E07A-series
** 00–06 ECA1 (hybrid)
** 88–98 ...
Everything Prelude! Pictures, write-ups, product reviews...PreludePower.com3Geez.com
Sources
3rd Generation Honda Prelude Engine Stats
{{Honda
B20A
1985 introductions
Straight-four engines