B-series block crank & head combos

B16, B18, B20
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B-series block crank & head combos

By teal_dx
- Fri Nov 10, 2006 5:10 pm #477 Crank Rod R/S Ratio Displ. Deck Delta
(* denotes interference with head)
B17A B17A 1.6200 1.804 8.930
B17A B20B 1.6830 3.800
B17A B20A 1.7537 1.950*
B17A B20B 1.6830 3.800
B16A B20A 1.8539 1.707 0.250
B18C B20A 1.6370 1.933 4.850*
B18C B20B 1.5711 0.900
B18C B18C 1.5814 0.000
B21A B21A 1.4916 2.106 2.150*
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By chnzgoofball
- Tue Jan 23, 2007 8:05 pm #1647 b21a?? is that still out of a crv??
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By teal_dx
- Tue Jan 23, 2007 8:46 pm #1649 It is in some of the 4th gen Ludes I believe.

edit: I did some research:

The B20A, B20A3, and B20A5 engines consisted of closed-deck aluminum blocks with thicker-than-average iron sleeves where as the B21A1 had some special material.

The B21A1 was basically a re-worked B20A5 with an increase in bore to 83 mm. The external block dimensions had to stay identical 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. These sleeves are so strong that they often do not lose their factory cross-hatching marks after 200,000 miles! A lot of B21A1 engines burn oil and have low cylinder compression numbers because the FRM material is so strong that it tears up piston rings. Good news though, you can usually replace the piston rings without any honing to the sleeves and go another 100,000+ miles without any sleeve wear.

B21A

(16-valve, DOHC, PGM-FI)

* Found in:
o 1990-1991 Honda Prelude Si States
* Very rare, it was only produced for the "Si States" models in Japan
* Power: 185

B21A1

(16-valve, DOHC, PGM-FI)

* Found in:
o 1990-1991 Honda Prelude Si
* Power: 140 hp @5800 rpm
* Torque: 135 lb.ft @5000 rpm
* Engine cc: 2056.03
* Cylinder cc: 514.0075
* Deck cc: 10.191
* Head cc: 51.0
* Compression Ratio: 9.4:1

Torque (lb.ft. @ rpm): 135@5000


I wanna see somebody boost the hell out of a B21A... wonder how much those sleeves can take :twisted:
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By chnzgoofball
- Tue Jan 23, 2007 9:50 pm #1650
I wanna see somebody boost the hell out of a B21A... wonder how much those sleeves can take


oo ok thanks for the info man... but yeah i wanna see that too hahaha
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By asianrob
- Wed Jan 24, 2007 3:13 am #1667 the B series motor out of the prelude wont be able to use the B series parts out of integra/civic.... they mount different and what not,....Just about everyt thing for civic/integra wont work on there except for a few miscellaneous parts of an LS integra...
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