Reinforced valve spring kit Mitsubishi 4G63T

€848.66 (tax incl.)

Reinforced valve spring kits for the Mitsubishi 4G63T engine.

Brands: FERREA, SUPERTECH
Engines: 4G63T (Eclipse, Talon, Lancer Evolution VIII)
Springs: double
Contents: springs, titanium upper retainers, lower spring seats, depending on the kit

SPRK-M1005D

Brand - Type of Springs: SUPERTECH - SPRINGS DOUBLE 80 LBS

On order, 15 to 30 days lead time

The Mitsubishi 4G63 turbo engines covered

These five kits are aimed at the 4G63T, the 2.0 litre, 16-valve turbo four-cylinder of the first two generations of Eclipse and Eagle Talon, then of the Lancer Evolution VIII. The KT4012 belongs to the Eclipse range, the KT4013 to the Evolution VIII; the three SUPERTECH kits are for the same engine.

In the FERREA kits the brand specifies its own lower spring seat: the original one is set aside. The factory spring, upper retainer and collets also give way to the kit parts, with a titanium upper retainer. The SUPERTECH kits replace the spring, the upper retainer and the lower spring seat; the original collets stay in place.

FERREA and SUPERTECH reinforced valve spring kit

The spring has to reseat the valve as soon as the lobe moves on. At high rpm it loses control: the valve leaves the cam, lands late and can strike the piston, known as valve float.

The KT4012 supplies 16 double springs: 356 N on the seat at 34.0 mm, 801 N at 10.0 mm of lift. The firmer KT4013 gives 423 N at 30.6 mm and 1001 N at 10.0 mm. The three SUPERTECH kits, all with double springs, give 356 N at 39.6 mm (SPRK-M1005D), 445 N at 39.0 mm (SPRK-M1007D-2) and 489 N at 38.1 mm (SPRK-M1007D-3).

Valve spring kit technical specification

Part number	Brand	Springs	Outer / inner Ø	Seat pressure	Open pressure	Rate	Max lift	Kit contents
KT4012	FERREA	Double	Outer 29.5 / 22.8 mm Inner 22.8 / 17.1 mm	356 N at 34.0 mm	801 N at 10.0 mm	44.5 N/mm	13.5 mm	16 springs, 16 titanium upper retainers, 16 lower spring seats, 16 collets
KT4013	FERREA	Double	Outer 30.5 / 22.9 mm Inner 22.9 / 17.5 mm	423 N at 30.6 mm	1001 N at 10.0 mm	57.3 N/mm	12.5 mm	16 springs, 16 titanium upper retainers, 16 lower spring seats, 16 collets
SPRK-M1005D	SUPERTECH	Double 80 lbs	Outer 28.1 / 20.0 mm Inner 20.0 / 15.2 mm	356 N at 39.6 mm	890 N at 11.5 mm	46.7 N/mm	16.0 mm	springs, titanium upper retainers, lower spring seats, valve stem seals
SPRK-M1007D-2	SUPERTECH	Double 100 lbs	Outer 28.1 / 20.0 mm Inner 20.0 / 15.2 mm	445 N at 39.0 mm	1081 N at 11.5 mm	55.6 N/mm	14.3 mm	springs, titanium upper retainers, lower spring seats, valve stem seals
SPRK-M1007D-3	SUPERTECH	Double 110 lbs	Outer 28.1 / 20.0 mm Inner 20.0 / 15.2 mm	489 N at 38.1 mm	1125 N at 11.5 mm	55.6 N/mm	13.4 mm	springs, titanium upper retainers, lower spring seats, valve stem seals

Valve spring kit fitting details

Part	Mitsubishi original	Reinforced spring kit
Spring		Kit specific: S10036 (KT4012) or S10084 (KT4013), double; SPR-M1005D (SPRK-M1005D) or SPR-M1007D (SPRK-M1007D-2 and SPRK-M1007D-3), double
Retainer		Kit specific: E11005 (KT4012) or E11052 (KT4013), titanium; RET-M65/T1 (SPRK-M1005D) or RET-M65/TSTD (SPRK-M1007D-2 and SPRK-M1007D-3), titanium
Spring seat		Kit specific: SL1009 (KT4012) or SL1041 (KT4013), original seat discarded; SEAT-M1007D (SPRK-M1005D and SPRK-M1007D-2) or SEAT-M1007D/FP (SPRK-M1007D-3)
Collets		Kit specific: K10035 (FERREA kits); original kept (SUPERTECH kits)

Each FERREA kit contains 16 double springs, 16 titanium upper retainers, 16 lower spring seats and 16 K10035 collets. The KT4012 receives parts S10036, E11005 and SL1009; the KT4013 receives S10084, E11052 and SL1041. In the FERREA kits the original lower spring seat is not reused. Each SUPERTECH kit contains double springs, titanium upper retainers, lower spring seats and VS-H6.6E valve stem seals: SPR-M1005D, RET-M65/T1 and SEAT-M1007D for the SPRK-M1005D; SPR-M1007D, RET-M65/TSTD and SEAT-M1007D for the SPRK-M1007D-2; SPR-M1007D, RET-M65/TSTD and SEAT-M1007D/FP for the SPRK-M1007D-3.

Installed height is measured with the valve closed, between the lower and upper bearing faces of the spring. The quoted loads hold at the heights given in the table above; each millimetre gained costs the load one spring rate (see above). Maximum lifts appear in the specification table. Measure the height on every valve before fitting.

	FERREA	SUPERTECH
Installed height	34.0 mm (KT4012) 30.6 mm (KT4013)	39.6 mm (SPRK-M1005D) 39.0 mm (SPRK-M1007D-2) 38.1 mm (SPRK-M1007D-3)
Seat pressure at this height	356 N (KT4012) 423 N (KT4013)	356 N 445 N 489 N

Technical guide

Our brands

	FERREA has been based in Florida since 1978. Founded by engine builders of Argentine origin, the company builds racing valves, springs, retainers and tappets: stock cars, dragsters, circuit single-seaters. Its special-alloy springs are proven in competition.
	SUPERTECH is a Californian firm that has designed valvetrain parts for competition for thirty years. Every batch of springs is inspected: X-ray, ultrasound and laser measurement. The range also covers valves, guides and retainers, fitted on the road as well as on the track.

How to choose

A firmer spring holds the valve against the cam at an engine speed the original cannot manage: you can aim for a more aggressive camshaft, a bigger turbo or higher boost without seeing the valve float. The five kits differ by seat load: 356 N for the KT4012, 423 N for the KT4013, then 356 N, 445 N and 489 N for the three SUPERTECH kits. Set your camshaft lift against the maximum lift of the chosen kit, from 12.5 mm to 16.0 mm depending on the kit: it must stay below. The right load beats the maximum load, since excess wears cams and tappets.

Criterion	Key point
Choosing the pressure	To choose between the five kits, begin with the lift of the camshaft, the rpm aimed for and the boost level. Spring rates run from 44.5 to 57.3 N/mm: the higher it is, the faster the load builds with lift. At SUPERTECH, 80 lbs equals 356 N, 100 lbs 445 N and 110 lbs 489 N. A load beyond the need tires cams and tappets.
Single or double spring	Every kit uses a double spring: a pair of nested coils split the load and absorb vibration better than one lone coil. FERREA states its titanium upper retainers are 40% lighter than steel, so the spring has less mass to follow.

When reinforced springs become necessary

Camshaft lifting above stock
Maximum engine speed pushed clearly higher
Bigger turbo or increased boost pressure
Head rebuilt for track or rally
Worn factory springs, valve float near the rev limit

Compatible vehicles

Model	Engine code	Years
Eclipse I (D2_A) 2.0 Turbo, 2.0 Turbo 4WD	4G63T	1989-1995
Eclipse II (D3_A) 2.0 Turbo, 2.0 Turbo 4WD	4G63T	1994-1999
Eagle Talon 2.0 TSi Turbo, Turbo AWD	4G63T	1989-1998
Lancer Evolution VIII (CT9A)	4G63T	2003-2007

Important: these kits are for the turbo 4G63 of the Eclipse, Eagle Talon and Lancer Evolution VIII. The other Evolutions and the naturally aspirated versions are not covered on this page. One FERREA kit of 16 fits a complete engine.