SUPERTECH inlet valve stem seals BMW M50TU M52 M54

BMW engines concerned

These seals fit the 6 mm stem inlet valves of the BMW 24-valve inline six-cylinder petrol engines: the M50 in its VANOS versions (M50B20TU and M50B25TU, from September 1992), the M52 in 2.0, 2.5 and 2.8 litre form, the M52TU, the M54 in 2.2, 2.5 and 3.0 litre form, as well as the S50B32 and S54B32 M3 engines and the North American S50B30US and S52B32US versions.

These engines have 12 inlet valves per cylinder head, two per cylinder. The original seal caps the guide and wipes oil along the stem; BMW supplies it in seal set 11 34 9 064 457 for the M50 VANOS, M52, M52TU, M54, S50B32, S54B32, S50B30US and S52B32US.

SUPERTECH inlet valve stem seals

The stem seal lets through just enough oil to lubricate the valve stem in its guide, and no more: without that oil, the stem and guide wear. Once worn or hardened by heat, the seal lets oil run down into the combustion chamber: oil consumption, blue smoke on start-up or after a long idle, deposits on the valves and spark plugs.

SUPERTECH inlet seals are moulded from a high quality rubber compound, a polyacrylate (ACM), and fit an 8.8 mm outside diameter guide for a 6 mm stem. The set of 12 covers every inlet valve of one cylinder head; the hotter exhaust side takes seals in a dedicated high-temperature compound, sold separately.

Stem seal technical specifications

Stem seal installation

Technical guide

The brand offered

SUPERTECH, born in San Jose in Silicon Valley, has been designing racing valvetrain parts for more than 30 years, from valves to stem seals. Its production is checked by ultrasonic testing, X-ray and laser measurement, then developed with leading engine builders.

Inlet or exhaust?

Both seals have the same dimensions but not the same material: the inlet takes the VS-VBM6-I polyacrylate (ACM) seal, the exhaust the VS-VBM6-E Viton (FKM) seal, designed for the higher temperature of the exhaust valves. Polyacrylate withstands up to 177 °C (350 °F); Viton, 204 °C (400 °F) continuous according to SUPERTECH. These BMW six-cylinders need 12 of each.

When valve stem seals must be replaced

• Oil consumption, blue smoke on start-up or after a long idle
• Valve removal or cylinder head rebuild
• Valve guide replacement
• Fitting reinforced valves or springs

Vehicle compatibility

BMW

OEM part number (BMW stem seal set): 11 34 9 064 457 (M50 VANOS, M52, M52TU, M54, S50B32, S54B32, S50B30US, S52B32US)

Remember the exhaust valve stem seals

Inlet valve stem seals are replaced together with the exhaust valve stem seals. We offer the SUPERTECH seals for these engines: