Reinforced valve spring kit Honda K20C1

Honda engine covered

This kit equips the 2.0 litre 16-valve turbo K20C1 engine of the Honda Civic Type R, from the FK2 generation to the FL5.

The single springs in the kit take the place of the standard ones and arrive with their retainers, lower spring seats and collets. With FERREA, both kits also bring lower spring seats and collets.

SUPERTECH and FERREA reinforced valve spring kits

With the lobe behind it, the spring alone must bring the valve home before the next lift. As revs climb, inertia pushes back: lacking load, the valve parts from the cam, seats late and may meet the piston. a fault named valve float.

The SUPERTECH kit holds 16 single springs: 343 N on the seat at 40.6 mm installed height, 783 N at 10 mm lift. The FERREA kits KT4033 and KT4038 also hold 16 single springs; the KT4038 has titanium upper retainers, 40 % lighter than steel according to FERREA, and a roller rocker.

Valve spring kit technical specification

Valve spring kit fitting details

The SUPERTECH kit contains 16 single springs, 16 upper retainers, 16 lower spring seats and 32 collets. The FERREA kit KT4033 contains 16 single springs S10165, 16 tool steel upper retainers E20056, 16 lower spring seats (SL1151 inlet, SL1152 exhaust) and 16 collets K10116. The KT4038 contains 16 single springs S10166, 16 titanium upper retainers E11142, 16 lower spring seats (SL1153 inlet, SL1154 exhaust), 16 collets K10116 and one RR1006 roller rocker.

Measured with the valve at rest, installed height is the gap running from the lower spring seat beneath the coil up to the retainer crowning it. The 343 N is exact at 40.6 mm only. A wider gap, for instance after a valve seat is recut or a head is skimmed, takes load off in proportion to the rate; the table below recalls the reference value.

Technical guide

Our brands

	SUPERTECH is a Californian specialist in valvetrain parts for competition, with three decades and more behind it. Its springs are drawn from steel wire containing chrome, silicon and vanadium, and each lot is then inspected by ultrasound, radiography and laser, one lot at a time.
	FERREA works out of Florida, where it was founded in 1978. Its design office draws valves, springs, retainers, tappets and roller rockers, all machined in the firm's own workshops, for racing as readily as for tuned road cars, with spring kits supplied complete.

How to choose

Firmer springs let the valve follow the cam at speeds stock parts forbid: a higher limiter, livelier camshafts or more boost no longer bring bounce. The SUPERTECH kit gives 343 N on the seat at 40.6 mm; beyond 13.8 mm of net lift it is out of range, so keep the camshaft below that. The two FERREA kits also use single springs and differ by upper retainer: tool steel for the KT4033, titanium for the KT4038, supplied with a roller rocker.

When reinforced springs become necessary

• Cam profile lifting more than standard
• Limiter raised well beyond stock
• More turbo pressure, or a larger turbo
• Head prepared for circuit or hill-climb use
• Tired factory springs, or bounce high in the revs

Compatible vehicles

Related products

Head on the bench? Before fitting these springs, have the valves and guides examined, so the engine is stripped only once. Parts offered for this engine: