BMW M21D24

BMW M21D24The BMW M21D24 is a 2.4 L (2,443 cc, 149.1 cu·in) straight-six four-stroke naturally aspirated or turbocharged liquid-cooled internal combustion diesel engine, manufactured by BMW Motoren GmbH Steyr since 1983 to 1992. The engine was manufactured on Steyr Plant (Upper Austria).

Cylinder bore and piston stroke are 80.0 mm (3.15 in) and 81.0 mm (3.19 in), respectively. Compression ratio rating is 22.0:1.

Naturally aspirated version of the M21D24 engine produced 85.7 PS (63 kW; 85.0 HP) at 4,600 rpm of maximum horsepower and 152 N·m (15.5 kg·m, 112 ft·lb) at 2,500 rpm of maximum torque. Turbocharged version with mechanically controlled fuel pump produced 115.6 PS (85 kW; 114.0 HP) at 4,800 rpm of horsepower and 210 N·m (21.4 kg·m, 154.8 ft·lb) at 2,400 rpm of peak torque. Engine version with electronically controlled fuel pump (after 1987) produced 220 N·m (22.4 kg·m, 162.4 ft·lb) at 2,400 rpm of peak torque

The BMW M21D24 features:

  • Cast-iron cylinder block
  • Aluminum cylinder head with belt-driven single overhead camshaft (SOHC)
  • Based on the BMW M20 engine, but has reinforced connecting rods, cylinder heads, pistons, valves and a crankshaft
  • 2 valves per cylinder (12 in total)
  • Swirl chamber injection
  • Mechanical fuel pump (before 1987) or electronically controlled fuel pump (after 1985)
  • Garrett T03 turbocharger (without an intercooler)
  • “Instant start” glowplug system for faster engine startup
  • Liquid-cooled cooling system
  • Electric starter (12V, 2.2 kW)

General information

Engine Specifications
Engine modelM21D24
Engine type4-stroke, SOHC, straight-six
Fuel typeDiesel
Displacement2.4 L, 2,443 cm3, (149.1 cu·in)
Max. horsepower Naturally aspirated version (after 1985):
85.7 PS (63 kW; 84.5 HP) at 4,600 rpm
Turbocharged version:
115.6 PS (85 kW; 114.0 HP) at 4,800 rpm
Max. torque Naturally aspirated version (after 1985):
152 N·m (15.5 kg·m, 112 ft·lb) at 2,500 rpm
Turbocharged version:
210 N·m (21.4 kg·m, 154.8 ft·lb) at 2,400 rpm
220 N·m (22.4 kg·m, 162.4 ft·lb) at 2,400 rpm
Cooling systemLiquid-cooled
Power adderGarrett T03 turbocharger (without an intercooler)
Fuel system Mechanically controlled fuel pump
Electronically controlled fuel pump (BoschEDC management system)
Starting systemElectric starter (12V, 2.2 kW)
Firing order:1-5-3-6-2-4
Dimensions (L x W X H)
Dry weight

Cylinder Block and Head

Cylinder block
Cylinder block alloy:Cast-iron
Compression ratio:22.0:1
Cylinder bore:80.0 mm (3.15 in)
Piston stroke:81.0 mm (3.19 in)
Cylinder internal diameter (standard):80.000-80.010 mm (3.1496-3.15 in)
Piston skirt outer diameter (standard):79.965 mm (3.1482 in)
Number of piston rings (compression / oil):2/1
Side clearance (Second):0.050-0.080 mm (0.002-0.0031 in)
Side clearance (Oil):0.030-0.060 mm (0.0012-0.0024 in)
Ring end gap (Top):0.200-0.400 mm (0.0079-0.0157 in)
Ring end gap (Second):0.200-0.400 mm (0.0079-0.0157 in)
Ring end gap (Oil):0.250-0.500 mm (0.0098-0.0197 in)
Number of main bearings:7
Crankshaft main journal diameter:60.000 mm (2.3622 in)
Crankpin journal diameter:44.975-44.991 mm (1.7707-1.7713 in)
Crankshaft center distance:40.5 mm (1.595 in)
Cylinder head
Cylinder head alloy:Aluminium
Valve arrangement:SOHC, belt driven
Valves:2,(12 valves in total)
Head height:148.000 mm (5.8268 in)
Valve head diameter (INTAKE):35.000 mm (1.378 in)
Valve head diameter (EXHAUST):31.000 mm (1.2205 in)
Valve steam diameter (INTAKE):7.000 mm (0.2756 in)
Valve steam diameter (EXHAUST):7.000 mm (0.2756 in)

Service Data

Cylinder compression:20.4 kgf/cm2 (2.0 MPa, 290 psi)
Valve clearance
Intake valve clearance (HOT):0.35 mm (0.0138 in)
Exhaust valve clearance (HOT):0.35 mm (0.0138 in)
Oil system
Oil type:Semi-synthetic
Recommended oil:SAE 5W-30, 10W-30
Oil capacity:5.8 L (6.13 US. qt, 5.1 Imp. qt.)
Oil pressure: 0.5 bar (0.51 kg/cm3; 7.25 psi) at Idle speed
5.0 bar (5.1 kg/cm3; 72.5psi) at Rated speed
Glow plug
Glow plug:Bosch 0 205 201 008, Champion CH159, Lucas/CAV HDS218


1. BMW TIS (Technical Information System)

Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

ATTENTION! Dear visitors, this is an informational database of technical specifications, we are not a parts supplier or a marketplace.

We try to use official documentation and verify the published data, but errors may occur. In addition, specifications of machinery and equipment may vary depending on markets and modifications. We do not recommend the use of this data for spare parts or repairs. Use official service manuals or parts catalogs for your product.

Be the first to comment

Leave a Reply

Your email address will not be published.