Honda B20A engine

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Partially unrelated to the Honda B-series engines are the B20A and B21A. By some, these are not considered to be part of the B-series group of engines because they are not compatible with most of the other B-series parts and all of the other B series chassis.

There were 2 versions of the B20A

• The first generation of B20A engines was available in the 86-87 Prelude 2.0SI in Japan and Europe, the 86-89 Honda Vigor and Accord . It leaned towards the front of the car just like the A20A engine found in the same cars. This B20A produces 160 hp (119 kW) and 140 lb·ft (190 N·m) torque in Japan. In Europe this called B20A1, produces 137 hp (102 kW) and 172 Nm.

• • There was also a similar engine named B18A for the 86-89 Accords. It was a destroked B20A powered by 2 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 lay 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 due to 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 where as the B21A1 had FRM (fiber reinforced metal) cylinder liners.

The B21A1 was basically a re-worked B20A5 with an increase in bore to 83 mm (3.3 in). 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 called FRM (fiber reinforced metal) which basically consisted of a carbon fiber matrix, aluminum alloy, and aluminum oxide to make a very strong cylinder sleeve. But, the 2.1L engine is notorious for burning oil. A lot of B21A1 engines burn oil and have low cylinder compression numbers. The original 2.0L (USDM B20A5 and JDM B20A) engine did not suffer the same problem. Good news though, you can usually replace the piston rings without any honing to the sleeves and go another + 100,000 miles (160,000 km) without any sleeve wear^{[citation needed]}.

[edit] 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~
    • 1985-1986 Honda Prelude Non-U.S.
    • 1985-1986 Honda Accord Non-U.S.
    • 1985-1986 Honda Vigor Non-U.S.
  • Serial numbers 1600001~ and 1640001~
    • 1987-1989 Honda Prelude jdm only -non u.s. b-20a5
    • 1987-1989 Honda Vigor Non-U.S.
• Displacement: 1958 cc
  • bore: 81 mm (3.2 in)
  • stroke: 95 mm (3.7 in)
• Compression: 9.4:1; 9.5:1
• Power:
  • (JDM GOLD TOP B20A 1986-1987) 160 hp (119 kW) @ 6300 rpm & 186 N·m @ 4000 rpm, using PH3 ECU
  • (JDM BLACKTOP B20A 1988-1989) 145 hp (108 kW) @ 6300 rpm & 186 N·m @ 4000 rpm, using PH3 ECU
  • (EDM, B20A1 Gold Top) 137 hp (102 kW) @ 6000 rpm & 172 N·m @ 4000 rpm, using PJ5(602,603,752),PJ7,PH3 ECU w vac. advance
• Transmission: B2K5, F2K5

[edit] B20A2

(16-Valve, 4 Cylinder, DOHC, PGM-FI)

• Found in:
  • 1987-1989 Honda Accord Non-U.S.
• Power: 142 hp (106 kW) @ 6200 rpm

[edit] B20A3

(12-valve, SOHC, dual side-draft carburetors)

• Found in:
  • 1988-1990 Honda Prelude 2.0 S
• Power: 104 hp (78 kW) @ 5800 rpm (MT)With cata, 115 hp (86 kW) @ 5800 rpm without cata
• Torque: 111 lb·ft (150 N·m) @ 4000 rpm
• It was PGM-CARB microprocesor controlled (pk-1)

[edit] B20A4

(12-Valve, SOHC, dual side-draft carburetors)

• Found in:
  • 1988-1991 Honda Prelude Non-U.S.

[edit] B20A5

(16-valve, DOHC, PGM-FI)

• Found in:
  • 1988-1991 Honda Prelude 2.0Si
• Power: 135 hp (101 kW) @ 6200 rpm (USDM)

145 hp (108 kW) @ 6200 rpm (JDM)

• Torque: 127 lb·ft (172 N·m) @ 4000 rpm
• Engine cc: 1958.14
• Cylinder cc: 489.535
• Deck cc: 13.885
• Head cc: 47.3
• Compression Ratio: 9.0:1

[edit] B20A6

(16-Valve, DOHC, PGM-FI)

• Found in:
  • 1988-1991 Honda Prelude Non-U.S. New Zealand, and Australian Domestic Market

142 hp (106 kW)@6000 rpm 174 nm@4500 rpm KY model is one of them

[edit] B20A7

(16-Valve, DOHC, PGM-FI)

• Found in:
  • 1988-1991 Honda Prelude Non-U.S. UK, France, Holland, Norway, South Africa
• Power 150 hp (112 kW)@6000 rpm
  • Torque 180 Nm@5500 rpm
    • Compression ratio 10.5:1

[edit] B20A8

(16-Valve, DOHC, PGM-FI)

• Found in:
  • 1988-1991 Honda Prelude Non-U.S. Russian, Swedish Domestic Market
  • 1988-1989 Honda Accord Non-U.S.
• Power 133 hp (99 kW)

[edit] B20A9

(16-Valve, DOHC, PGM-FI)

• Found in:
  • 1990-1991 Honda Prelude Non-U.S. Finland, German, Norway, Netherlands, Russia, Argentina
• Power 140 hp (104 kW)@6000 rpm
  • Torque 175 Nm@4500 rpm
    • Compression ratio 10.5:1

B20a9 engine code stamp

[edit] B21A

(16-valve, DOHC, PGM-FI)

• Found in:
  • 1990-1991 Honda Prelude Si States
• Very rare, it was only produced for the "Si States" models in Japan
• Power: 145 hp (108 kW)
• Torque: 186 N·m (137 lbf·ft)
• Compression Ratio: 10.5:1^{[citation needed]}

engine using a pk-3 honda ECU

B21a	B21a engine code stamp

[edit] B21A1

(16-valve, DOHC, PGM-FI)

• Found in:
  • 1990-1991 Honda Prelude SI USDM
  • 1990-1991 Honda Prelude SR Canadian Market
• Power: 140 hp (104 kW) @5800 rpm
• Torque: 135 lb·ft (183 N·m) @5000 rpm
• Engine cc: 2056.03
• Cylinder cc: 514.0075
• Deck cc: 10.191
• Head cc: 51.0
• Compression Ratio: 9.4:1

Block casting - FRONT

Block casting - REAR

[edit] See also

• List of Honda engines
• 3Geez.com

[edit] Sources

• Honda Prelude JDM Engines
• 3rd Generation Honda Prelude Engine Stats