Basic engine information
Identifying your engine.
M10 and S14 have the engine number located on the transmission mating surface, on the
left side, just above the starter motor. There is also an engine code in the same
place
M20 has both numbers located below the oil pump drive shaft access point, left side of
the engine just behind the power steering pump.
M42 has the engine number and code located on the left rear of the block at the oil pan
mounting surface.
In all cases, the engine number consists of two groups of 4 numbers. e.g. 1234
5678 and the engine code consists of 5 digits.
The first number of the first group is the engine ID. 0 or 1 = M10 or M42, 2 or 3 =
M20, 6 = S14
Next 3 numbers represent a unique serial number
First number of the second group is the plant code. 0 - 4 for Munich , 5 - 9 for Steyr
The last 3 numbers of the second group are the production day (Julian date).
The engine number for new or remanufactured consists of 2 groups of 4 numbers like the
production versions, but the meaning is different.
The first 4 numbers are a sequential serial number
Next is code A for remanufactured, or N for new engine.
Next two are month, last digit is the last digit of the year.
The first two digits of an engine code give the engine capacity in liters, e.g. 27 =
2.7 Liter. Next number is amount of cylinders, next letter is E for injection, V for
carburetor, T for turbocharged, S for sequential fuel injection or K for Catalyst. Final
letter is either an internal BMW code, or a country code.
Engine codes are as follows :
Engine
|
M10B18
|
S14B23
|
M42B18
|
M20B25
|
M20B27 (pre 88)
|
M20B27 (from 88)
|
Cylinders
|
4 |
4 |
4 |
6 |
6 |
6 |
Stroke
|
|
84mm (3.307") |
81mm |
75mm |
81mm |
81mm |
Bore
|
|
93.4mm (3.677") |
84mm |
84mm |
84mm |
84mm |
Displacement
|
|
2302 cc |
1796 cc |
2494 cc |
2693 cc |
2693 cc |
Compression ratio
|
|
10.5:1 |
10:1 |
8.8:1 |
9.0:1 |
8.5:1 |
Combustion chamber volume
|
|
43.0 ± 0.5 cc |
|
40.2 ± 1 cc |
|
|
Compression pressure
|
|
14 bar |
10 - 11 bar |
10 - 11 bar |
|
|
Camshaft duration
|
|
248° |
240° |
|
|
|
Intake valve diameter
|
|
37mm |
33mm |
42mm |
|
|
Exhaust valve diameter
|
|
32mm |
30.5mm |
36mm |
|
|
Valve clearance (cold)
|
|
0.28 - 0.33mm |
Non adjustable |
0.25mm |
|
|
Oil pressure at max rpm
|
|
4.0 - 5.0 bar |
4.0 bar |
4.0 - 5.0 bar |
|
|
Oil capacity
|
|
4.65 liter +0.3 for new filter |
4.5 liter + 0.36 for new filter |
4.75 liter +0.75 for new filter |
|
|
Thermostat
|
|
80° C |
88° C |
80° C |
|
|
Firing order
|
1-3-4-2 |
1-3-4-2 |
1-3-4-2 |
1-5-3-6-2-4 |
1-5-3-6-2-4 |
1-5-3-6-2-4 |
Spark plugs
|
|
Bosch X5DC |
|
Bosch W8LCR |
|
|
Plug gap
|
|
0.6 + 0.1mm |
0.9mm |
0.7 + 0.1mm |
|
|
Power
|
|
192hp/143kW @ 6750 rpm |
134hp/100kW @ 6000rpm |
168hp/123kW @ 5800 rpm |
121hp/90kW @ 4250 rpm |
127hp/95kW |
Torque
|
|
169 ft/lbs. / 230 Nm @ 4750 rpm |
127 ft/lbs. / 172 Nm @ 4600 rpm |
164 ft/lbs. / 222 Nm @ 4300 rpm |
170ft/lbs. / 230 Nm @ 3250 rpm |
171 ft/lbs. / 230 Nm |
Idle speed
|
|
880 ± 50 rpm |
850 ± 40 rpm |
760 ± 40 rpm |
|
|
Max engine speed
|
|
7240 ± 80 rpm |
6500 ± 40 rpm |
6400 ± 80 rpm |
|
|
Max sustained engine speed
|
|
6900 rpm |
|
|
|
|
Required fuel
|
87 AKI (91 RON) |
93 AKI |
90 AKI (96 RON) |
87 AKI (91 RON) |
|
87 AKI (91 RON) |
