The standard form of such an identification number (for petrol engines, as opposed to diesel engines) is as follows:
ABBCDE
Where:
A = Exhaust emission standard ahered to by the engine in question (in this case, they are European Community directives pertaining to emission limits). One of the following:
'C' = Catalytic Converter (EC 91/441/EEC)
'X' = EuroII (EC 91/441/EEC (stage 2))
'T' = OBDII
'U' = ?
'Y' = ?
'Z' = ?
'A' = ?
Where there is no letter, the engine adheres to EC directive ECE R 83 A.
BB = Engine capacity in cubic centimetres (cc). This is a two digit number - e.g. '20' means 2.0 litres, '35' means 3.5 litres.
C = Compression Ratio. One of the following:
'G' = less than or equal to 8.5:1
'L' = 8.5:1 to 9.0:1
'N' = 9.0:1 to 9.5:1
'S' = 9.5:1 to 10.0:1
'X' = 10.0:1 to 11.5:1
'Y' = more than or equal to 11.5:1
D = Mixture system. One of the following:
'E' = Multi-point fuel injection
'Z' = Central injection / TBI (Throttle Body Injected)
'V' = Carburettor
'L' = LPG (Liquified Petroleum Gas)
E = Specific vehicle version. This is often not used, and little information exists on the meaning of all the variants of this segment of the code. Some of them are:
'H' = High output / Supercharging or Turbo
'V' = Volume model
'R' = Raised Performance / Increased output
'T' = Turbo
'L' = Low End Torque
'D' = Deawoo / GMDAT
As an example, one of Vauxhall/Opel's recent engines, the X25XE (going through the identification in part order):
X - adheres to EC emission directive EC 91/441/EEC (stage 2)
25 - has a 2.5 litre capacity
X - has a compression ratio of 10.0:1 to 11.5:1
E - has multi-point fuel injection.
In addition to this, if one were to search out the engine number of the particular engine (as found stamped on the engine block, usually in front of the clutch housing), one would likely find an extended version of the code as described above, with further details in the form:
ABBCDEFFGGGGG
ABBCDE are as described above.
FF = Country of manufacture. One of the following:
'01' = Rüesselsheim
'02' = Bochum
'08' = Ellesmere Port
'14' = Kaiserslautern
'19' = Aspern
'20' = Hungary
'25' = Holden
'31' = Brazil
'0S' = Szentgotthard
GGGGG is the engine serial number.
(thank Piro for the find)
