Brian Crower

Honda K20A/K20Z

The newest engine in the Honda tuning community. The "K Series" is Honda's mass produced version of the roller rocker valve train assembly found in the S2000. Less friction, more rpm potential, faster action cam profiles...this engine has untapped potential. First introduced in the JDM Integra Type-R in 2001, this engine put out a respectable 220HP @ 8000 rpm straight from the factory (DC5). The K20A also sees service in the JDM Civic Type-R, using the same compression and cam profiles. The first USDM production model was the K20A2 found in the 02-04 RSX-S. Other engines featuring the same head configuration include the K24A2 (TSX) that features a 9.114" deck height, the K20Z1 in the 05-06 RSX-S that includes various JDM Type-R add-ons like cams, throttle bodies, higher compression and Honda's answer to the tuning crowd, the K20Z3 found in the 2006-up Civic Si.

Stage	Description	Cam #	Adv. Dur.	Dur @ .050	Lift (in)	Lift (mm)	Kit #
	Forced Induction Specification Short duration profile builds cylinder pressure by reducing overlap, high lift for more air intake. Requires kit BC0040 or BC0040S.	BC0041	296°/300° 248°/248° 245°/245°	222°/224° 182°/182° 182°/182°	.520"/.497" .367"/.367" .325"/.325"	13.21/12.62 9.32/9.32 8.25/8.25	BC0040 or BC0040S
	Normally Aspirated Specification Hot street/strip or road race spec. Use with CAI, H, E, ECU, A/F mods. Excellent street manners and idle quality. Requires kit BC0040 or BC0040S.	BC0042-2	304°/300° 252°/252° 246°/246°	234°/228° 186°/186° 178°/178°	.525"/.472" .357"/.357" .313"/.313"	13.34/11.99 9.07/9.07 7.95/7.95	BC0040 or BC0040S
	Normally Aspirated Specification Intended for fully built engine. Extensive modifications, high compression pistons. Also works on K24 all motor. Requires kit BC0040 or BC0040S.	BC0043	314°/310° 256°/256° 250°/250°	244°/240° 190°/190° 184°/184°	.525"/.518" .369"/.369" .323"/.323"	13.34/13.15 9.37/9.37 8.20/8.20	BC0040 or BC0040S
	USDM K20A2 (RSX-S)	Stock	302°/305°	219°/215°	.483"/.431"	12.27/10.95
	USDM K24A2 (TSX)	Stock	310°/302°	210°/212°	.451"/.453"	11.45/11.50
	JDM K20A (DC5)	Stock	320°/318°	224°/219°	.483"/.424"	12.27/10.77

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 titanium retainers are CNC machined from 6AL4V round bar titanium to exacting tolerances. Use steel retainer for high mileage applications.

Kit #	Spring #	Retainer #	Seat #	Description
BC0040	BC1040	BC2010	BC2904	Dual spring, titanium retainer/seat
BC0040S	BC1040	BC2011	BC2904	Dual spring, steel retainer/seat
BC0040X	BC1040	BC2010	No Seat	Dual spring, titanium retainer
BC0040SX	BC1040	BC2011	No Seat	Dual spring, steel retainer

Spring Pressure:
BC1040 Seat: 1.590" @ 80 lbs / Open: 1.110" @ 250 lbs / Coil Bind: 1.030" (no machine work required)

If running 2006-up K20Z3 cylinder, you may need to purchase BC2940 keepers to accommodate the BC2010 or BC2011 retainers.

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)

K20A/K20Z 2.35L STROKER KIT
K24 BLOCK 2.6L

• BC 4340 billet steel crankshaft (102mm stroke K24 / 92mm stroke K20).
• BC 4340 Pro Series custom steel billet rods w/ARP2000 bolts (.935" BE width).
• CP aluminum forged pistons (any bore size, any compression ratio).
• 5100 Series carbon steel alloy wrist pins. 9310 pin upgrade available.
• Ductile iron plasma top rings, tapered second ring, low tension oil rings.
• High strength ACL Race Series bearings included.
• Fully system balanced and ready to install.

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 connecting rods (modified BE bore and BE width).

Stock Specifications:
K20A/Z 86mm Bore x 86mm Stroke - 8.350" Block Height
K24A 87mm Bore x 99mm Stroke - 9.114" Block Height

LEFT COLUMN