Reinforced valve spring kit Hyundai Kia G4FJ

The Hyundai and Kia G4FJ engine

The G4FJ is the 1.6 litre turbocharged, direct-injection, 16-valve four-cylinder found across the Hyundai and Kia ranges: Veloster, i30, Tucson, Kona, Elantra, Ceed, Cerato, Sportage, Optima, Soul and their Chinese cousins, from 2012 to today.

The kit replaces the standard spring and its lower seat; the original upper retainer is kept with the first kit, while the second brings its own.

SUPERTECH reinforced valve spring kit

As the cam lets the valve go, the spring has to press it back onto its seat without lingering. As revs climb, inertia holds the valve back: too little load lets it bounce, close late and come near the piston. That is valve float.

Both kits give 334 N on the seat at 33.5 mm, then 765 N at 10.0 mm of lift, for a maximum lift of 11.3 mm.

Valve spring kit technical specification

Valve spring kit fitting details

The SPRK-MC56BE-G4FJ pairs the SPR-MC56BE conical spring with the original upper retainer, the SS-C202 lower spring seat and KPR-5.5A-LG collets; the SPRK-MC56BE-G4FJ-2 swaps the original upper retainer for the RET-MC56-HY.

For installed height, valve closed, take the distance between the spring's two bearing points: the seat under the spring and the retainer above it. The 334 N is only guaranteed at 33.5 mm. The longer that dimension gets, after a head skim for instance, the lower the load falls, by the rate for every millimetre. Measure every valve before fitting.

Technical guide

Our brands

SUPERTECH designs competition valvetrain parts in California and has more than thirty years behind it. Before shipping, each production run of springs is checked by X-ray, ultrasound and laser. Its range also covers valves, guides and retainers, from road cars to the track.

How to choose

More load keeps the valve following the cam when engine speed exceeds what the stock spring follows: raised limiter, more aggressive camshaft, higher boost. Both kits offer 334 N on the seat at 33.5 mm and 765 N at 10.0 mm of lift. Reason from the real need: a spring that is too firm tires cams and tappets. The 765 N figure at 10.0 mm of lift tells you what the spring pushes back with at full opening, when the valve is under the most strain.

When reinforced springs become necessary

• Camshaft sharper than the stock one
• Rev limiter raised by the tuner
• Larger turbo or higher boost pressure
• Head reworked for track or competition use
• Tired springs, valves floating before the limiter

Compatible vehicles

Related products

Head open? Have valves, guides and seats checked at the same time: one teardown is enough and closing stays crisp with new springs. Check the seals too.