The Honda B20A series is a line of four-cylinder inline engines produced by Honda. The B20A was first introduced in 1985 as a displacement upgrade for the Honda Prelude and was later used in the Honda Accord and Honda Vigor.
The engine featured a 2.0-liter displacement and was available in both naturally aspirated and forced induction versions. The B20A engine was known for its reliability and longevity and was produced until 1991.
The Honda B20A: A Review Of Its Technical Specifications
There are two engines in the B-series that are not closely related to those in the Honda B-series, the B20A and B21A. Due to the fact they are incompatible with most other B-series parts and chassis, these are not considered to be a part of the B-series group.
There Were 2 Versions Of The B20A
In Japan and Europe, the first generation of B20A engines was available in the 1986-87 Honda Prelude 2.0SI as well as the 1986-89 Honda Vigor and Accord. It leans toward the front, as with the A20A engine in the same vehicles.
This B20A delivers 160 PS (118 kW) and 140 lb-ft (190 N⋅m) torque in Japan. This engine is known as the B20A1 in Europe, and it produces 137 horsepower (102 kW) and 127 lb. ft (172 Nm).
B18A engines were available for the 86-89 Honda Accords as well. Keihin carbs powered two side draft Keihin engines de-stroked B20A.
In the Prelude of the years 88–91, B20A was found in its second generation. Prelude blocks B20A and B21A are cast at an angle of 18 degrees, facing toward the firewall.
Due to the ultra-low hood line, which Honda refers to as its “engineless design,” and for handling reasons, this was done to meet the exterior specifications of the 1988–1991 3rd Generation Prelude.
As the engine is at an angle, it has a lower center of gravity (similar to the straight 6-engine design used by older BMWs). Aluminum blocks were used for the B20A, B20A3, and B20A5 engines. Unlike the aluminum blocks, the B21A1 cylinder liners of the B21A1 were made of fiber-reinforced metal (FRM).
B21A1
Based on the B20A5, the B21A1 was essentially a reworked B20A5 with a bore increase of 83 mm (3.3 in). It was necessary to maintain the external block dimensions of the B21 (although it has been strengthened externally and webbing has been added) to those of the B20A5.
A carbon fiber matrix, aluminum alloy, and aluminum oxide were combined in a fiber-reinforced metal (FRM) to produce a very strong cylinder sleeve. Honda called on Saffil to provide it.
Sleeves of this strength wear out piston rings, causing low compression numbers, high oil usage, and severe smoking.
For example, replacing worn rings can usually revive a motor’s former output in many cases. As this sleeve type will delaminate during machining, many machine shops do not attempt to re-hone or rebore these sleeves.
Final Words
The first Japanese vehicles with the B20A engine are the 1986–1987 Honda Prelude 2.0Si and the 1986–1989 Honda Vigor or Accord.
From 1987-1991, the B20A was used in various forms in the Honda Prelude, but its underlying principles were quite different than those of the B16/B17/B18.
A Honda B-Series engine’s reliability and ability to produce high horsepower relative to its displacement have made it one of the most sought-after engines in the world.
As well as being readily available, they can also be found at reasonable prices. As well as being transplantable into various Honda chassis, including the Honda Civic, the B-Series engine has a number of other benefits.
The question is: how does one determine whether or not the FRM has full integrity prior to buying a Prelude with a B20A motor?
To determine whether or not the FRM has full integrity prior to buying a Prelude with a B20A motor, you can perform a visual inspection of the engine block and look for any signs of cracks or damage.
Additionally, you can perform a compression test to check the engine’s overall health and ensure that it is running smoothly. If you are still unsure, it is recommended that you take the vehicle to a trusted mechanic for a more thorough inspection. I hope this helps.