FERREA exhaust valve stem seals Mitsubishi Hyundai 4B11-T G4KF

Mitsubishi and Hyundai engines concerned

For the 5.5 mm stem exhaust valves of the Mitsubishi 4B11-T, a 2.0 litre 16-valve turbo four-cylinder, this set takes the place of the factory seals. It also suits the Hyundai G4KF. These engines are found in the Lancer Evolution X, the Lancer Ralliart and the Genesis Coupe 2.0 T.

On the exhaust side, the head has 8 valves, two per cylinder. On each guide, Mitsubishi fits an original seal that spreads oil over the stem, number MN183952, the same as on the inlet.

FERREA exhaust valve stem seals

On an exhaust valve, the seal endures the heat of the gases leaving the cylinder. When it hardens, settles or splits, oil is no longer stopped: it seeps along the stem, is consumed with the gases and leaves blue smoke, higher consumption and deposits on valves and ports. It must nevertheless let a very fine film of oil through so that stem and guide do not wear.

This FERREA seal is made of Viton (FKM), a compound rated for high temperatures, paired with a spring that tightens the lip on the 5.5 mm stem to retain oil when the turbo engine is used to the full. The brand intends these seals for tuned and race engines. With these 8 seals the entire exhaust of the 4B11-T or G4KF is covered; on the inlet side, FERREA offers a Viton seal too, sold separately.

Stem seal technical specifications

Stem seal installation

Technical guide

The brand offered

FERREA manufactures its whole valvetrain itself in Florida and Argentina, valves and stem seals alike, in-house. Its parts are made for competition and high-output engines, and the spring fitted to each Viton seal keeps it tight even at very high revs.

Inlet or exhaust?

The exhaust VS1024, rated for high temperatures, and the inlet VS1025 are both made of Viton (FKM), each fitted with a lip spring for a 5.5 mm stem. FERREA still assigns each one to a side of the 4B11-T, and they are not mixed at assembly. Each side takes 8 seals.

When valve stem seals must be replaced

• Increased oil use, blue smoke
• Valves out, head brought back to new
• Valve guides changed
• Uprated springs or valves fitted

Vehicle compatibility

OEM part number (Mitsubishi stem seal): MN183952

Remember the inlet valve stem seals

The 8 exhaust seals of the 4B11-T or G4KF are changed with the 8 inlet seals. For these engines FERREA offers the VS1025 set: