During the 1970s, BMW produced a prototype V8 engine for the E23 7 Series, however this engine did not reach production. Development of the M60 began in 1984.
Design
The M60 engine has double overhead camshafts with four valves per cylinder. The camshaft is driven by a dual-row timing chain with a self-adjusting tensioner. Valves had hydraulic lash adjustment to reduce maintenance. The ignition and fuel injection systems are controlled by the Bosch Motronic 3.3 system, and the ignition system is a coil-on-plug design with knock sensors. To reduce weight, the engine uses aluminum for both the engine block and cylinder head, magnesium valve covers and a plastic intake manifold. The M60 was BMW's first car engine to use a "split conrod" design, where sintered connecting rods are made as a single piece and then fractured in order to ensure increased rigidity and an exact fit. The dry weight of the engine is between and.
Versions
M60B30
The M60B30 has a bore of and a stroke of, for a displacement of. Compression ratio is 10.5:1, giving an output of at 5800 rpm and at 4500 rpm. Applications:
The M60B40 has a bore of and a stroke of, for a total displacement of. Compression ratio is 10.0:1, giving at 5800 rpm and at 4500 rpm. It had a forged crankshaft. Applications:
produced a high compression version of the M60B40 for the BMW Alpina B10 4.0 and the B11 4.0 and in some B8 4.0 models produced for the Japanese market. The M60 engine produced in the B10 4.0. The engine's displacement was later enlarged to for use in the B8 4.6 and B10 4.6. The power output is in the B10 4.6 and in the B8 4.6.
The M60 uses Nikasil- an alloy containing aluminium, nickel and silicon alloy- to line the cylinders bores. In fuels with high sulfur content, the sulfur damages the Nikasil bore lining, causing the engine to lose compression. In the U.S. and U.K., sulfur rich fuel is being phased out. BMW replaced engines under warranty and Nikasil was eventually replaced by Alusil. Nikasil engines are unlikely to be a problem today, as cars with affected engines are off the road or have received replacement engines.
