BMW M47

BMW M47 built into a BMW E87

The BMW M47 and Rover Group M47R are diesel straight-4 engines. Variants were manufactured by BMW from 1998 to 2007. BMW gradually adopted high-pressure common rail fuel injection systems over the lifetime of the M47. All BMW engines of this period came with thermostats that gradually deform, which causes them to trigger engine cooling at increasingly lower temperatures and worsening fuel economy.

M47D20

The original M47 diesel engine featured non-common-rail direct fuel injection and a 1951 cc block. First seen in 1998, the M47D20 produced 100 kW (136 hp) and 280 N·m (207 lb·ft) in its original 320d/520d guise, and 85 kW (114 hp) with 265 N·m (195 lb·ft) in the 318d variant. All M47 engines have one Swirl and one Tangential intake port per cylinder, which can each improve performance under different conditions. These features are not to be confused with Swirl Flaps^[1] , which were introduced in the M47TUD20.

Applications:

• 85 kW (114 hp) and 265 N·m (195 lb·ft)
  • 2001-2003 E46 318d
• 100 kW (136 hp) and 280 N·m (207 lb·ft)
  • 1999-2001 E46 320d
  • 2000-2003 E39 520d

M47R

Rover Group (UK) and Steyr (Austria), both subsidiaries of BMW, collaborated on re-engineering the M47D20 to create a transverse configuration for use in the Rover 75 front wheel drive saloon, as well as their all wheel drive Land Rover Freelander. The same engine was later deployed by MG Rover in the Rover 75 Tourer and MG ZT. The general configuration of an M47R ("M47 Rail") differs to the original design by the introduction of common-rail technology, a transverse orientation, different turbochargers, and more sophisticated temperature management systems. However, the core 1951 cc heads of the M47R and M47D20 are the same. Combining a common-rail system with a relatively small engine capacity created engine temperature problems. More hardware was added to help control temperatures which also helped to escalate weight, fuel consumption, and manufacturing costs. The BMW Steyr plant manufactured and supplied M47R engines with the same power output as the M47D20 from 1999 to 2006.

Applications:

• 1999-2004 Rover 75 CDT
• 1999-2005 Rover 75 CDTi
• 2001-2006 Land Rover Freelander
• 2001-2004 MG ZT CDT
• 2001-2005 MG ZT CDTi

M47TUD20

The all wheel drive BMW X3 and rear wheel drive BMW 320d models, built approximately between September 2001 and December 2004, were fitted with the M47TU ("M47 Technical Update"). The exact production week is not known, and was probably later than Production Week 33 in 2001 (e.g. one cannot rely on a UK 51 plate registered BMW 320d to have the M47TU).

The engine capacity was expanded to 1995 cc, and it retained the common-rail injector system that had proven popular in the smaller M47R and larger M57 engines. These changes empowered BMW to increase torque and improve fuel consumption, especially at lower revs. However, these modifications added 50 kg to overall weight and emissions raised accordingly. In the UK, the new characteristics of the M47TU were sufficient to lift the BMW 320d into the next highest insurance bracket, and the next highest band for Vehicle Excise Duty (Road Tax).

The M47TU was fitted with twin balancer shafts to counteract the secondary balances inherent in an in-line four-cylinder engine. The M47TU was regarded as so good that BMW made it available in the 320Cd Coupé.

Although an extremely well accomplished piece of engineering, the M47TUD20 introduced new common failure points. Chief among these was a new 'swirl flap' mechanism embedded in the inlet manifold. This consisted of a number of butterfly valves within each individual inlet tract, which are secured to an actuating rod via two small screws. It has become clear that over time these screws can come loose via vibration etc. When this happens they can end up being drawn into the respective cylinder, causing significant damage to piston, cylinder head and valves. If unlucky further damage can be caused to the turbo if the screw then makes its way through the exhaust valve into the manifold and subsequently into the turbo. These failures have occurred in such quantity that a number of specialist BMW magazines have featured articles on the problem including information on how to remove the swirl flaps ^[2] .^[3] For those who wish to perform some preventive maintenance on the M47TUD20 engine, there are companies who supply and/or fit blanking plugs to allow the removal of these swirl flaps altogether. BMW adressed the problem by introducing stronger swirl flaps and larger diameter spindles - made from plastic - in 2006.

Applications:

• 85 kW (114 hp) and 280 N·m (207 lb·ft)
  • 2003-2005 E46 318d
• 110 kW (148 hp) and 330 N·m (243 lb·ft)
  • 2001-2005 E46 320d
  • E83 X3 2.0d (up to end of 2006)

M47TU2D20

The engine was updated again in 2004 as the M47TU2D20. Still at 1995 cc, it produced more power across the range.

Applications:

• 90 kW (121 hp) and 280 N·m (207 lb·ft)
  • E87 118d
  • E90/E91 318d
• 120 kW (161 hp) and 340 N·m (251 lb·ft)
  • E60/E61 520d
  • E87 120d
  • E90/E91 320d
  • E83 X3 2.0d (end of 2006 onwards)

See also

• List of BMW engines

References

External links

• BMW diesel engine "SWIRL FLAPS" all you ever ever need to know about Swirl flaps!

• Total BMW magazine may 2009