Reinforced valve spring kit Honda Acura K24Z3 K24Z7

€1,383.36 (tax incl.)

Kit of 16 reinforced valve springs for the Honda and Acura 2.4 K24Z3 and K24Z7 engines.

Brand: FERREA
Engines: K24Z3 and K24Z7 (Accord, Civic, CR-V, Acura TSX and ILX)
Springs: dual
Contents: springs, titanium upper retainers, lower spring seats, collets

The Honda and Acura engines covered

This kit fits the 2.4 litre, 16-valve i-VTEC four-cylinder of the K series, in its K24Z3 form (Accord VIII and IX, Acura TSX) and its K24Z7 form (Civic IX, CR-V III and IV, Acura ILX), built from 2007 to about 2016.

FERREA plans for the original spring, upper retainer, lower spring seat and collets to be replaced by the parts of its kit. The original lower spring seat is set aside.

FERREA reinforced valve spring kit

Once the peak of the lobe is cleared, the spring pulls the valve down against its seat. At high revs the valve gets hard to hold: it bounces, lifts off the cam and may hit the piston: valve float.

Each kit holds 16 dual springs, each made of two nested coils: 467 N on the seat at 39.0 mm, then 1001 N for 10.0 mm of lift.

Valve spring kit technical specification

Part number	Brand	Springs	Outer / inner Ø	Seat pressure	Open pressure	Rate	Max lift	Kit contents
KT4005	FERREA	Dual	Outer 31.0 / 23.1 mm Inner 23.1 / 17.4 mm	467 N at 39.0 mm	1001 N at 10.0 mm	53.4 N/mm	15.0 mm	16 springs, 16 titanium upper retainers, 16 lower spring seats, 16 collets
KT4054	FERREA	Dual	Outer 31.0 / 23.1 mm Inner 23.1 / 17.4 mm	467 N at 39.0 mm	1001 N at 10.0 mm	53.4 N/mm	15.0 mm	16 springs, 16 upper retainers, 16 lower spring seats, 16 collets

Valve spring kit fitting details

Part	Honda original (K24Z3)	Reinforced spring kit
Spring	14761-R44-A01 (inlet), 14762-R44-A01 (exhaust)	Kit specific: S10164 (dual)
Retainer	14765-R40-A00	Kit specific: E11141 (titanium) or E20062
Spring seat	14775-PCX-000	Kit specific: SL1149
Collets	14781-RGM-A01	Kit specific: K10034

The FERREA KT4005 kit includes 16 S10164 dual springs, 16 E11141 titanium upper retainers, 16 SL1149 lower spring seats and 16 K10034 collets. The original lower spring seat is not refitted. The KT4054 kit is identical, with E20062 upper retainers in place of the E11141.

Installed height is read with the valve shut, between the two retainers, from the lower bearing face to the upper bearing face of the spring. The 467 N figure is quoted at 39.0 mm; fitted higher, the spring loses its rate at every millimetre gained in height (previous table). Kit lift does not exceed 15.0 mm, the point at which the coils almost touch.

	FERREA
Installed height	39.0 mm
Seat pressure at this height	467 N

Technical guide

Our brands

FERREA was born in Florida in 1978, set up by Argentine engine builders living in the United States. Tappets, retainers, springs and valves all come out of its own workshops, and they equip NASCAR cars as well as dragsters and circuit single-seaters.

How to choose

Stiffening the springs allows more revs, a more incisive cam profile or stronger boost, without the valves floating. Each kit offers 467 N on the seat and 1001 N at 10.0 mm lift. Before buying, read off the lift of your camshaft: it must stay under 15.0 mm, the limit of the kit. A few minutes of measuring avoid an unsuitable purchase. The right setting is the tightest fit: too low and the valve floats, too high and the valvetrain wears faster.

Criterion	Key point
Choosing the pressure	Three figures fix the load required: camshaft lift, the target rev ceiling and any boost. When one rises, the load must follow, without crossing the lift limit of the kit. Here, 467 N on the seat at 39.0 mm. A load above the need achieves nothing and wears the cams and followers.
Single or double spring	The dual spring pairs two concentric coils that share the effort and calm vibration better than a single spring. Each kit also comes with collets, lower seats and upper retainers, titanium in the KT4005. The titanium upper retainers, which FERREA rates 40% lighter than steel, reduce the mass the spring has to follow.

When reinforced springs become necessary

Camshaft with lift above the standard one
Rev ceiling raised well above factory
Higher turbo or supercharger pressure
Head prepared for track, hill climb or rally use
Worn factory springs, valves that float

Compatible vehicles

Model	Engine code	Power	Years
Accord VIII 2.4 (CP)	K24Z3	193 hp	2007-2012
Accord VIII Coupé 2.4 (CS)	K24Z3	193 hp	2007-2012
Accord VIII 2.4 i (CU2)	K24Z3	201 hp	2008-2015
Accord VIII Break 2.4 i (CW2)	K24Z3	201 hp	2008-2015
Accord IX Coupé 2.4	K24Z3	188 hp	2012-
Civic IX 2.4 (FB6)	K24Z7	204 hp	2011-2016
Civic IX Coupé 2.4	K24Z7	204 hp	2012-
Civic IX Coupé 2.4	K24Z7	188 hp	2014-
Civic IX Coupé 2.4	K24Z7	206 hp	2014-2015
CR-V III 2.4 4WD	K24Z7	188 hp	2011-2012
CR-V IV 2.4 (RM3, RM1)	K24Z7	188 hp	2012-2016
Acura TSX 2.4	K24Z3		2009-2014
Acura ILX 2.4	K24Z7		2013-2015

OEM part number (valve spring): 14761-R44-A01 (inlet), 14762-R44-A01 (exhaust)

Important: this kit is for the K24Z3 and K24Z7 engines. The K24A, K24Z1, K24Z2, K24Z6, K24Z9 and the K24W7 of the Acura TLX are not covered. One kit of 16 fits a complete engine.