CATCAMS mechanical tappets BMW M50 M50TU E36 E34

The BMW engines concerned

This kit fits the 24-valve cylinder head of the BMW M50 inline six, in 2.0 and 2.5 litre form, across both generations: the M50 without VANOS, up to September 1992, and the M50TU with intake VANOS, from then on. These engines powered the BMW 3 Series E36 (320i, 325i) and 5 Series E34 (520i, 525i).

As standard, each valve is operated by a 35 mm diameter hydraulic tappet. Both generations take the same CATCAMS CC005 tappet; only the lash cap changes with the valve stem diameter, 7 mm without VANOS and 6 mm with VANOS.

CATCAMS CC005 mechanical tappets

The tappet, or bucket, is the part the cam lobe slides on. It transmits the camshaft's motion to the valve stem. The original hydraulic tappet contains a piston fed by engine oil. The CATCAMS mechanical tappet is a solid bucket, without a piston, that presses on a lash cap fitted on the valve stem.

Tappet manufacturer INA (Schaeffler) points out that direct actuation by mechanical bucket tappets stands out for its high rigidity and very small moving masses, which ensure excellent performance at high engine speeds. The low tappet mass also reduces the load required from the valve springs, and therefore friction losses.

For the M50 without VANOS and for the M50TU, CATCAMS offers camshafts designed for this conversion, which it calls « solid lifter conversion ». The kit contains the 24 CC005 tappets for one cylinder head, 35 mm in diameter. The lash caps are sold separately, in thicknesses from 1.00 to 6.00 mm in 0.05 mm steps.

Tappet technical specifications

Tappet installation

For each generation, CATCAMS publishes the following complete setup with its CC005 tappets:

Technical guide

The correct lash caps are essential: TS102 for 7 mm stems, TS101 for 6 mm stems.

The brand offered

CATCAMS is a Belgian manufacturer specialising in engine valve trains. It designs its own cam profiles and grinds its camshafts on CNC grinding machines, and completes its range with tappets, lash caps, springs and retainers. Its camshafts have raced in the BTCC and at the 24 Hours of Le Mans.

What the conversion requires

• A camshaft designed for mechanical tappets
• 24 TS102 (M50 without VANOS) or TS101 (M50TU) lash caps, in the appropriate thicknesses

Vehicle compatibility

OEM part numbers (hydraulic tappet): 11 32 1 734 341 (M50 without VANOS); 11 32 1 739 299 (M50TU with VANOS)