REMOVAL & INSTALLATION
The M20 and M30 single overhead camshaft engines use rocker arms that are removed in the process of removing the rockershafts. To remove the rockershafts, it is impossible not to remove the rocker arms. See rockershaft/arm removal in this section.
The double overhead camshaft engines use a direct valve actuation through a bucket and shim as on the S14 and S38 engines or a hydraulic lash adjuster as one the M42 and M50 engines.
The bucket and shim lifters on the S14 and S38 engines are removed after the camshafts have been removed. Mark their locations and lift them from their bores. The lifters must be replaced in the original positions. Measure the lifter bore with an inside micrometer and the outside diameter of the lifter with an outside micrometer. The difference should be 0.0010-0.0026 inch (0.025-0.066mm).
The hydraulic lifters in the M42 and M50 engines are kept in the bearing plates for most operations. They can be held in place using bmw tool 11 3 250 or equivalent. Check the lifters for scoring and wear.