Honda B20A engine
| Honda B20A engine | |
|---|---|
| Overview | |
| Manufacturer | Honda |
| Production | 1985–1991 |
| Combustion chamber | |
| Configuration | DOHC inline four |
| Chronology | |
| Successor | Honda B engine |
The Honda B20A engine series, known as the B20A and B21A was an inline four-cylinder engine family from Honda introduced in 1985 in the second-generation Honda Prelude. Also available in the contemporary third-generation Honda Accord in the Japanese domestic market, along with the Accord-derived Vigor, the B20A was Honda's first line of multivalve DOHC inline four-cylinder engines, 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.
It would be succeeded by the Honda B engine. 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 must not be confused with other B-series engines and the B20B, a 2.0 liter DOHC engine introduced alongside the Honda CR-V in 1994.
There were two versions of the B20A:
The B20A, B20A3, and B20A5 engines consisted of closed-deck aluminum blocks with thicker-than-average iron sleeves whereas 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. 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.
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