Reinforced valve spring kit Mitsubishi 6G72

€1,393.73 (tax incl.)

Reinforced valve spring kit for the Mitsubishi 6G72 3.0 V6 24V engine.

Brand: SUPERTECH
Engines: 6G72
Springs: double
Contents: springs, titanium upper retainers, lower spring seats

Mitsubishi engines covered

This kit is for the 6G72, Mitsubishi's 3.0 litre V6 with a single overhead camshaft per bank and 24 valves, found under the bonnet of the early-2000s Eclipse and of the Montero, known in Europe as the Pajero.

The twin-cam 6G72 of the 3000 GT and the GTO, like the 12-valve 6G72 versions, is not covered here: their springs belong to other kits.

SUPERTECH reinforced valve spring kit

The spring keeps the valve shut on its seat and calls it back behind the cam. At high revs a fast-moving valve leaves the cam if the spring lacks reserve: it bounces on closing and threatens the piston. More firmness removes that float.

At 41.36 mm installed the kit gives 334 N at the seat and 792 N at 10 mm lift, net lift 16.6 mm.

Valve spring kit technical specification

Part number	Brand	Springs	Outer / inner Ø	Seat pressure	Open pressure	Rate	Max lift	Kit contents
SPRK-M2521-T1	SUPERTECH	Double	Outer 26.4 / 19.3 mm Inner 19.3 / 14.5 mm	334 N at 41.36 mm	792 N at 10 mm	44.5 N/mm	16.6 mm	Springs, titanium upper retainers, lower spring seats

Valve spring kit fitting details

Part	Mitsubishi original	Reinforced spring kit
Spring		Kit specific: SPR-M2521/T1
Retainer		Kit specific: RET-M2521/T1 (titanium)
Spring seat		Kit specific: SEAT-TS-SUB4 (to be machined to 26.90 mm diameter)
Collets		Original kept

The SUPERTECH kit comprises the M2521/T1 double springs, the RET-M2521/T1 titanium upper retainers and the SEAT-TS-SUB4 lower spring seats. The manufacturer asks for the diameter of this lower seat to be reduced to 26.90 mm; the original collets stay in place.

Valve shut, installed height is read from the bearing face of the lower seat up to the upper retainer locked by the collets: 41.36 mm for this kit. With a rate of 44.5 N/mm, one millimetre more or less takes away or adds as many newtons of seat load. The kit reference is repeated right alongside, together with the matching loads.

	SUPERTECH
Installed height	41.36 mm
Seat pressure at this height	334 N

Technical guide

Our brands

SUPERTECH is a Californian brand born in racing. It designs spring, retainer and valve ranges for tuned engines of all kinds. Its wire of alloyed steel (chrome, silicon, vanadium) is coiled, then put through ultrasound and radiography before each batch ships.

How to choose

The bigger the seat load, the longer the valve stays in step with the cam when revs rise: the red line moves back, a livelier camshaft becomes possible and boost can be considered on a 6G72. This double spring nests two springs one inside the other; they share the work and smother their own vibrations. Its maximum net lift is 16.6 mm, and the camshaft must stay well clear of it, so keep a comfortable margin below that limit. A load above the need wears the lobes faster: better to aim accurately and stick to the engine's real use.

Criterion	Key point
Choosing the pressure	Expressed in lbs, the number measures the seat load: 75 lbs make 334 N, and 792 N is reached at 10 mm of lift. Measure your camshaft lift and note the target revs before choosing; excess load brings nothing and needlessly strains lobes and rockers.
Single or double spring	Two concentric springs share the work in this kit. The upper retainer is titanium, lighter than a steel part; the kit's lower seat is included, to be machined to 26.90 mm in diameter.

When reinforced springs become necessary

Cam with higher lift than the original
Maximum revs pushed beyond the factory setting
Boost added to the 6G72
Heads rebuilt for competition
Worn springs or valve float noticed at high revs

Compatible vehicles

Model	Engine code	Power	Years
Montero (Pajero) 3.0 V6 24V	6G72		1995-2003
Eclipse 3.0 V6 24V	6G72		2000-2005

Important: this kit is for the 6G72 with a single camshaft per bank and 24 valves. The twin-cam 6G72 of the 3000 GT and the GTO, like the 12-valve 6G72 versions, is not covered on this page.