SUPERTECH inlet and exhaust valve stem seals MINI Cooper S W11B16A set of 8

MINI engines concerned

This set of 8 targets the supercharged 1.6 16-valve W11B16A four-cylinder, 6 mm stem, found in the R50 / R53 generation MINI Cooper S (Cooper S, Works, S Works, John Cooper Works) and the R52 convertible (Cooper S, John Cooper Works), between 163 and 218 hp, from 2002 to 2008.

On the W11, 8 valves serve the inlet and 8 the exhaust, and SUPERTECH fits all of them with the same integral seal. This set of 8 fills one row; two are needed for the whole head. Seated on the guide, the seal regulates the oil sliding down the stem.

SUPERTECH inlet and exhaust valve stem seals

Force-fed by its supercharger, the W11 runs hot around its seals: each must give the 6 mm stem just the oil it needs and return any excess upward into the head. Over time and heat the lip sets hard and no longer grips: oil is added between services, a blue haze escapes at start-up or when moving off after a long idle, and valves and plugs both foul.

At SUPERTECH, the VSI-M6E is an integral seal made of Viton (FKM) and dimensioned for an 11 mm guide and a 6 mm stem. The 8 pieces of the set equip one row of your choice, inlet or exhaust, since the same part serves both sides of the W11B16A.

Stem seal technical specifications

Stem seal installation

Technical guide

The brand offered

From San Jose, California, its home for 30 years and more, SUPERTECH turns out competition valves plus springs, guides and stem seals. Lots are screened by ultrasound, radiography and laser gauge, then respected tuners trial it on the dyno and at the track.

Inlet or exhaust?

For the W11B16A, SUPERTECH sticks to one part number: the VSI-M6E integral seal, in Viton (FKM), sits on the 8 inlet and on the 8 exhaust valves alike, with a 6 mm stem and an 11 mm guide. SUPERTECH puts this Viton's rating at 204 °C (400 °F) continuous, an asset on the exhaust of a supercharged engine. An engine needs 2 sets of 8.

When valve stem seals must be replaced

• Oil dropping and the W11 smoking blue at a cold start
• W11B16A head off for a rebuild
• Valve guides being changed
• New uprated springs or SUPERTECH valves

Vehicle compatibility

MINI

OEM part number (MINI stem seals): 11 34 0 029 571 (complete set)

Remember the W11B16A uprated valves

With the W11 head removed, check its 16 valves as well. SUPERTECH also makes uprated inlet valves for this very engine: