The M60 was BMW's powerful V-8 engine for over a
decade. The M60 was used in BMW models
like the E34
5 Series Sedan, the
Series and the E31
Work commenced on the BMW M60 in 1984 and the first V-8 was released
at the beginning of 1992. The engine was available in two versions, a 3-liter and the more recent
4-liter. The 3-liter V-8 develops 160kW at 5800 rpm and 288 Nm at 4500
rpm. The 4-liter engine has substantially more power with 210 kW at 5800
rpm and 400 Nm at 3900 rpm. The four camshafts are chain-driven and
operate 32 valves. The 4-liter engine uses a 10:1 compression ratio and a
common feature is the
manifold -- which flows very well -- and made of plastic.
Since 1997, the BMW M60 V-8s produce 3.5 and 4.4-liters
thanks to a larger bore and longer stroke. They share a compression ratio
of 10:1. Power stayed the same as the 4.0 with 210 kW at a slightly lower
rpm of 5700, but torque was lifted slightly to 420 Nm, still at 3900 rpm.
The 3.5 (like the 535i and 735i and iL) makes 180 kW at 5800 and 345Nm at
3800 revs. The 4.4-liter 540i/740i engine pushes a V12 equivalent 210kW at
5400 rpm and 440 Nm of torque at 3600rpm. Four valve technology,
cylinder-specific knock control and a direct fire DME engine management
system are used in both engines.
By using an aluminum cylinder block
with Nikasil plating of the bore surfaces and a reinforced-plastic inlet
manifold, it was possible to keep the engine weight very low at around 210
kg. The power-to-weight ratio for the 4.0-liter v-8 was 0.73 kg/bhp,
around 30% better than its cast-iron predecessor.
The design of the 4-valve cylinder head
used for the V-8 largely corresponded to the versions used on the four and
six-cylinder engines. A duplex chain from the crankshaft drove the two
inlet camshafts, from which the exhaust camshafts were driven by secondary
duplex chains. The camshafts were equipped with counterbalancing masses to
compensate for the free inertia forces of the valves.
For the first time, BMW installed a
"broken" connecting rod made of sintered material. By using sintering in
comparison to the more usual forging it was possible to manufacture a
connecting rod to very tight weight tolerances without machining. The
two-part nature of the connecting rod big end, which is needed for
assembly around the bearing on the crankshaft, was created by first making
the part as a single piece and then physically breaking the big-end cap
away. The raw, irregularly-broken structure permitted absolutely exact
repositioning on assembly.
The engine had electronic knock
detection, which facilitated a basic design that could be planned for the
use of a high compression ratio for low fuel consumption. As on the
smaller engines, static high-voltage ignition was used.