9mm Valve Adjusting Screw (Tappet) - 1900cc Waterboxer, 1600cc (CT Engine Code)

This replacement valve adjusting screw (tappet) is designed for use on VW Type 25 / T3 buses fitted with 1900cc Waterboxer engines and 1600cc CT or CZ aircooled engines, as well as selected late Beetle and Brazil Kombi applications. Featuring the correct M9 x 1.0mm thread, this adjuster is used in the rocker arm to set and maintain correct valve clearance.

The valve adjusting screw sits at the end of the rocker arm and contacts the valve stem. During adjustment, it allows precise setting of valve clearance, ensuring correct valve timing, quiet operation, and proper sealing of the valves. Accurate valve adjustment is essential for engine performance, longevity, and fuel efficiency—particularly on engines with hydraulic or mixed valvetrain configurations.

Manufactured as a direct replacement, this adjusting screw is ideal for replacing worn, damaged, or rounded originals. Over time, adjusting screws can suffer from pitting, mushrooming, or thread wear, leading to inaccurate valve settings and increased valvetrain noise. Renewing them during servicing or engine rebuilds helps restore smooth and reliable operation.

Fitting Notes

• Thread size: M9 x 1.0mm

• Sold individually

• 8 required per engine

• Always inspect rocker arms and valve tips during installation

• Lubricate threads and contact face before fitting

Engine Compatibility

Aircooled engines:

• CT – 1600

• CZ – 1600

• Beetle 1200 / 1300 / 1302 / 1303 (late models)

• Brazil Kombi 1.6 AR (Carb & EFI)

Waterboxer engines (1.9L):

• DF, DH, EY, GW, DG, SP

Vehicle Applications

• Volkswagen Beetle – 1978–1979

• VW Type 25 / T3 Bus – 1983–1992

• Brazil Kombi – 1997–2005