Exhaust valve guides SUPERTECH BMW MINI B46 B48

Applicable BMW and MINI engines

This set fits the exhaust side of the 2.0 turbo 16-valve four-cylinders from BMW and MINI, B46 and B48 families: B46A20A, B46A20B, B48A20A, B48A20B, B48A20E, B48A20F, B48A20H, B48A20P and B48A20S.

Each cylinder head has 8 exhaust valves, so 8 guides. On these engines the original BMW exhaust valve 11 34 8 621 264 has a 28.5 mm head and a 6 mm stem.

SUPERTECH exhaust valve guides

On the exhaust side, the guide holds the valve square to its seat, drains towards the head the heat the stem takes from the burnt gases and supports the stem seal. Growing clearance tips the valve, which then rests badly on its seat, and oil creeps along the stem: higher consumption, blue smoke and lower compression. Fitting a new guide restores precise support for the stem and steady closing of the valve.

The 8 guides of this SUPERTECH set, 47 mm long with a 10.045 mm outside diameter, are bored for the 6 mm stem of the exhaust valves and cover the whole exhaust side of a head. They are readily fitted with reinforced valves.

Valve guide technical specifications

Valve guide installation

Technical guide

On the exhaust side, here are the reinforced valves with a 6 mm stem offered for these engines:

Our brand

A Californian company, SUPERTECH has served racing for over thirty years; its guides and stem seals for the B46 and B48 come in sets of 8, one set per head.

When valve guides must be replaced

• Oil escaping along the exhaust valve stems
• Reinforced valves planned for an already worn head
• Racing engine to be rebuilt
• Valvetrain to be refurbished as a whole

Vehicle compatibility

Remember the inlet guides and valve stem seals

New guides call for new stem seals: the head is already stripped down, so it is sensible to take advantage of it.