Brian Crower BC2904 Valve Spring Seats Set of 16 for Honda K20A2 K20Z3 F20C F22C

Vehicle Fitment

• 2002-2004 Acura RSX Type-S (DC5, K20A2 2.0L I4 VTEC)
• 2005-2006 Acura RSX Type-S (DC5, K20Z1 2.0L I4 VTEC)
• 2006-2011 Honda Civic Si (FG2/FA5, K20Z3 2.0L I4 i-VTEC)
• 2000-2003 Honda S2000 AP1 (F20C 2.0L I4 VTEC)
• 2004-2009 Honda S2000 AP2 (F22C 2.2L I4 VTEC)

Fitment Notes

• Designed for use with Brian Crower BC1040 series dual valve springs; compatible with OEM spring dimensions on K20A2, K20Z1, K20Z3, F20C, and F22C cylinder heads.
• 16 seats required per engine - sold as a full set of 16 to cover all intake and exhaust valves.
• Replaces OEM spring seat shims when upgrading to aftermarket valve springs; check installed height before final assembly.

Features

• CNC machined from hardened 4140 round bar chromoly steel for precise tolerances and long-term durability under high-RPM valve train loads.
• Acts as a shim beneath each valve spring to allow controlled spring rotation at extreme coil bind, preventing spring walk and retainer separation.
• Stepped design seats the BC1040 dual spring securely, maintaining consistent installed height across all 16 valve positions.
• Lightweight at 9.0 grams each, minimizing added reciprocating mass while providing a robust platform for high-lift camshaft applications.
• System-matched for use with Brian Crower BC1040/BC1040T spring kits and BC2010/BC2011 retainers for verified valvetrain compatibility.
• Supports net cam lifts up to 0.620" / 15.74mm when paired with BC high-lift spring kits.

Specifications

• Part Number: BC2904
• Application: Honda/Acura K20A2, K20Z1, K20Z3, F20C, F22C
• Material: 4140 Hardened Chromoly Steel
• Compatible Spring: BC1040 / BC1040T Dual Valve Spring Series
• Compatible Retainers: BC2010 (Titanium), BC2011 (Steel)
• Outer Diameter (O.D.): 1.102"
• Step 1 Diameter: 0.844"
• Step 2 Diameter: 0.613"
• Weight per Seat: 9.0 grams
• Installed Seat Pressure (BC1040): 1.590" @ 80 lbs
• Quantity: Set of 16

Included Components

• 16x 4140 Chromoly Steel Valve Spring Seats

Product Description

The Brian Crower BC2904 valve spring seats are a precision-machined valvetrain component designed for Honda and Acura engines using the K20A2, K20Z1, K20Z3, F20C, and F22C cylinder heads. Sitting between the cylinder head spring pocket and the base of the valve spring, these seats serve a critical role - they allow the spring to rotate freely at maximum coil bind, preventing the spring from expanding off the retainer under high-RPM conditions. CNC machined from hardened 4140 chromoly steel and weighing just 9.0 grams each, they add virtually no reciprocating mass while delivering the precision fit needed for a reliable high-performance valvetrain.

The BC2904 is system-matched for use with Brian Crower's BC1040 and BC1040T dual spring kits and pairs with BC2010 titanium or BC2011 steel retainers. Whether building a naturally aspirated high-revving K-series or preparing the valvetrain for forced induction duty, these seats provide the stable foundation required for consistent spring installed heights across all 16 valve positions. Each set includes all 16 seats needed for a complete full-head installation.