GSC Power Division Honda K-Series

Valves: Chrome polished intake and exhaust valves for K20/K24 in standard head sizes and +1mm oversize.

Valve Guides: Manganese bronze intake and exhaust guides for K20/K24, including stopper style and i-VTEC specific exhaust guides, plus intake and exhaust guides for the K20C1 (Civic Type R FK8/FL5).

Browse related GSC listings at /collections/gsc-honda-k-series.

Identify your engine code before ordering. K20A, K20Z and K24 naturally aspirated heads generally use the K20/K24 listings, while the direct-injection turbo K20C1 fitted to the Civic Type R FK8 and FL5 uses its own dedicated guides. Note the valve stem diameter (6mm on many K-Series applications) and whether your head has been previously machined, as this affects guide style and whether standard or +1mm oversize valve heads are appropriate. Where a listing specifies i-VTEC, stopper style or a particular internal diameter, match that description to the machining spec your engine builder has nominated.

Valves and valve guides are cylinder head components and require the head to be removed and disassembled. Guide replacement normally involves pressing out the old guides, fitting the new guides to the correct height and reaming or honing to the specified clearance, followed by seat cutting and lapping. Installation by a professional engine machinist or qualified workshop is strongly recommended, along with correct valve stem seals, spring seats and a full valve clearance check on reassembly.

Do these valves suit both K20 and K24? Listings marked K20/K24 cover both families; check the stated head diameter and your engine code.

Are K20C1 parts the same as K20A parts? No. The K20C1 in the Civic Type R FK8/FL5 uses its own guide listings.

Do I need new valve guides when fitting oversize valves? Not always, but guide condition should be assessed by your machinist during the head rebuild.