A USDM only production engine, the K20A3 and similar cylinder head configurations were developed for a performance, yet economical mindset. Although VTEC, it is only featured on the intake camshaft. The K20A3 is found in the 01-03 Civic Si while the K24A1 is in the 01-03 CR-V. The K24A4 is the most popular of them all due to the fact that was used to service the 03-up Accord as well as the 02-03 Element. Because of it's tall deck height (9.114"), the trend will be to take these blocks and use the K20A/K20Z head found in the 06-up Civic, 01-06 RSX-S for more rpm potential and added tuning ability. However there will be plenty of tuners wanting to stay true and run the original K20A3 head.
|Stage||Description||Cam #||Adv. Dur.||Dur @ .050||Lift (in)||Lift (mm)||Kit #|
|Forced Induction/NA Street Specification|
Short duration profile builds cylinder pressure by reducing overlap, high lift for more air intake. Requires kit BC0050.
|Normally Aspirated Specification|
Hot street/strip or road race specification. Use with CAI, H, E, ECU, A/F mods. Excellent street manners. Requires kit BC0050.
|USDM K20A3 (Base RSX/Civic)||Stock||270°/276°||181°/173°||.372"/.383"||9.45/9.73|
|USDM K24A (Accord/CR-V)||Stock||270°/276°||181°/173°||.372"/.383"||9.45/9.73|
Rocker Ratio: 1.75:1 mid, 1.7:1 sec, 1.7:1 pri
No valve timing events due to variable intake cam.
VALVE SPRING/RETAINER KIT
Designed for high rpm, BC valve springs are wound from only the highest grade, super clean, chrome silicone alloy and feature proprietary processing procedures for consistent pressures. BC retainers and spring seats are CNC machined from 6AL4V titanium to exacting tolerances. Use steel retainer for high mileage applications.
|Kit #||Spring #||Retainer #||Seat #||Description|
|BC0050||BC1050||BC2050||No Seat||Single spring, titanium retainer|
|BC0040||BC1040||BC2010||BC2904||Dual spring, titanium retainer/seat|
|BC0040S||BC1040||BC2011||BC2904||Dual spring, steel retainer/seat|
BC1050 Seat: 1.567" @ 78 lbs / Open: 1.100" @ 206 lbs / Coil Bind: 0.972" (no machine work required)
BC1040 Seat: 1.580" @ 84 lbs / Open: 1.100" @ 250 lbs / Coil Bind: 1.030" (no machine work required)
STAINLESS STEEL VALVES
BC valves are made from premium stainless steel, fully machined and swirl polished for ultimate air flow. Dished head for added weight savings and increased valve control at high rpm. Standard and oversize head.
|Part #||Description #|
|BC3040||35.0mm Intake (standard head diameter)|
|BC3041||30.0mm Exhaust (standard head diameter)|
|BC3042||35.5mm Intake (+.5mm head diameter)|
|BC3043||30.5mm Exhaust (+.5mm head diameter)|
|BC3044||36.0mm Intake (+1mm head diameter)|
|BC3045||31.0mm Exhaust (+1mm head diameter)|
K20A3 2.35L/K24A 2.60L STROKER KIT
|Kit #||Crank #||Rod #||Piston #||Bearing #||Desc.|
|BC0044||BC5048||BC6058||BC7048||BC4020||92mm w/LW rods|
|BC0045||BC5048||BC6048||BC7048||BC4020||92mm w/heavy duty rods|
|BC0048||BC5049||BC6059||BC7049||BC4020||102mm w/LW rod|
|BC0049||BC5049||BC6049||BC7049||BC4020||102mm w/heavy duty rods|
The BC stroker kit for the Honda/Acura K Series engine platform incorporates the wider B16A bearing (.935" width) that offers more surface area than the .740" width bearing found in the OEM K Series crank and rod combination. The added surface area increases bearing life, especially at extended rpm. Note: This kit requires custom rods (BE bore and BE width).
K20A3 86mm Bore x 86mm Stroke - 8.350" Block Height
K24A 87mm Bore x 99mm Stroke - 9.114" Block Height