Reinforced valve spring kit Honda K20A K20Z K24 F20C F22C

The Honda K20A, K20Z, K24, F20C and F22C engines

The K20A is the 2.0-litre i-VTEC four-cylinder of the Civic Type-R (EP3, FD2), Integra and RSX (DC5); the F20C is the 2.0-litre VTEC of the S2000 (AP1). Both have sixteen valves, hence 16 springs, operated by rocker arms with adjusting screws.

On the K20A2, Honda fits springs 14761-PCX-003 on the inlet and 14762-PCX-003 on the exhaust, retainer 14765-PRB-A01, spring seat 14775-PCX-000 and valve locks 14781-PRB-A01; the F20C1 shares these springs and the spring seat, with retainer 14765-PCX-000 and valve locks 14781-PR7-A01.

SUPERTECH and FERREA reinforced valve spring kits

The spring closes the valve once the cam releases it, then keeps it on the profile. At the top of the rev range, once inertia overcomes the spring force, the valve leaves the cam, ricochets off its seat and sometimes ends up striking the piston.

The SUPERTECH kits range from 334 to 445 N seat pressure and from 956 to 1223 N at 12 mm lift, with titanium or steel retainers. The FERREA kits quote 423 to 712 N at 40.0 mm, with titanium retainers 40% lighter according to FERREA.

Valve spring kit technical specification

Valve spring kit fitting details

The SUPERTECH kits combine springs, retainers (RET-K20A2/T2 titanium, RET-HBK-ST steel on the -ST versions, RET-H55BE-T1 on the BE conical kits) and SEAT-H1020DS or SEAT-HKBE spring seats; SPRK-H1021S keeps the original spring seat. Each FERREA kit contains 16 double springs, 16 titanium retainers, 16 spring seats and 16 K10034 valve locks; the original spring seat is not refitted.

Installed height is, with the valve closed, the gap measured between the bearing surfaces of the two parts, spring seat and retainer. The SUPERTECH kits are quoted between 37.8 and 40.4 mm, the FERREA kits at 40.0 mm. Any reworking of the seats enlarges this dimension, and the real pressure then drops by the rate for each added millimetre: check all 16 valves.

Technical guide

Our brands

	Founded in California, SUPERTECH brings over three decades of experience to racing valvetrain parts. The company selects a refined chrome-silicon-vanadium wire for its springs and submits every lot to radiographic, ultrasonic and laser inspection before it leaves the workshop.
	Argentine engine builder Horacio Ferrea set up FERREA Racing Components, which bears his name, on Florida soil in 1978. Its springs, retainers, valves and guides, all produced in-house, are found in drag racing, NASCAR and long-distance endurance events.

How to choose

Being stronger, the spring stops the valve from letting go of its profile as revs increase: it allows bolder camshafts, a later rev limit or boost, free of valve float. The offer on this page covers 334 to 712 N seat pressure. One safeguard remains: your camshafts must never exceed the stated max lift, from 15.0 to 18.3 mm with SUPERTECH, 15.0 or 18.4 mm with FERREA depending on the kit.

When reinforced springs become necessary

• Camshafts with a livelier profile than stock
• Cut-off pushed back on K20A or F20C
• Turbo or supercharger fitted
• Head redone for competition use
• Valve float seen on the dyno or sagging original springs

Compatible vehicles

OEM part number (valve spring): inlet 14761-PCX-003 (or 14761-PRB-A02), exhaust 14762-PCX-003 (or 14762-PRB-A02).

Related products

While the head is open, have the valves and guides checked too: our inlet and exhaust valves suited to these two engines are listed just below.