SUPERTECH exhaust valve stem seals Audi S2 RS2 S4 S6 2.2 20V

Audi engines concerned

This set goes on the exhaust side of the Audi 2.2 20V turbo five-cylinder, whose valves have a 7 mm stem: RR of the Quattro 20V, 3B of the 200 20V Turbo quattro and early S2 Coupé, ABY of the later S2 Coupé and 80 S2, ADU of the RS2 Avant and AAN of the 100 S4 and A6 S6, from 1989 to 1997.

The head holds 10 exhaust valves, two per cylinder. Each carries an original seal on the guide that regulates the stem lubricating oil; Audi lists it as 027 109 675, 20 per engine, the intake taking the same seal.

SUPERTECH exhaust valve stem seals

In the hottest part of the engine, the exhaust stem seal takes the heat of the valve it surrounds. Once hardened or cracked, it lets oil slip along the stem towards the chamber, where it gets consumed: the level falls, blue smoke shows and carbon covers valve heads and port. A slight oil flow is still essential, without it stem and guide get damaged.

On the exhaust, SUPERTECH uses Viton (FKM) for its seals, a compound built for high heat and chosen to age more slowly under the warmth of these valves: the brand states this material makes them withstand higher temperatures, with 204 °C (400 °F) continuous. They find their place on a 9.8 mm outside guide, around a 7 mm stem. The 10 pieces dress the whole exhaust; on the intake, polyacrylate (ACM) seals form a separate set.

Stem seal technical specifications

Stem seal installation

Technical guide

The brand offered

Anchored in San Jose, in Northern California, SUPERTECH has produced racing valvetrain components for over 30 years. New designs are computed by finite elements, then put to the test by renowned builders on track, in rallying and at the drag strip.

Why two different materials?

Seals on both sides are the same size; heat is the difference, being far stronger on the exhaust side. SUPERTECH therefore gives the exhaust to the more resistant Viton (FKM) VS-VW7-E and the intake to polyacrylate (ACM) VS-VW7-I. The five-cylinder needs 10 of each.

When valve stem seals must be replaced

• Falling oil, blue exhaust smoke
• Valves removed, head being redone
• Valve guides replaced
• Uprated valves or springs to fit

Vehicle compatibility

Audi

OEM part number (Audi exhaust stem seal): 027 109 675

Remember the inlet valve stem seals

Replace the intake seals during this job too, since they sit in this same head. SUPERTECH supplies intake seals for the engine: