How to decipher your engine block..

[rs4pro3]

I was browsing threw the factory TIS cd, and found this data. And found it pretty interesting.
From the Factory BMW implemented an 8 digit code to I.D. variose engine blocks. For the m20 engines this code is located on the intake side under the cover for the oil pump driveshaft.
Here is a shot of the code on my 86 325es block

My code is 24376031
The First number stands for the assembly line
0 or 1=M10, M42
2 or 3=M20, M21, M50
4 or 5=M30
6=S14, S38, M70
So since my first digit is 2 my block is an m20

The next 3 numbers is the serial number of the block so mine is serial # 437

The 5th number shows which factory the block was built in
0-4=Munich
5-9=Steyr(Austria)
So my block was made in the Steyr plant

The last 3 digits stand for the production day, so mine was produced on day 31

Now if the engine has been replaced by BMW or rebuilt or if the engine was replaced during production there will be a seperate code stamped up above the engine number, representing the build info like displacement etc...

[MA325is88]

Great find!

[Avus E30]

wow now thats some serious research. I guess this would be the most defenite way to know your engine. That is if you couldnt tell any other way.

[ldsbeaker]

How about on the passenger side where it says "2.7l eta" on the block ??

[YAN-3]

great info. were did you find this out?

[SpunkyE30nOk]

How about on the passenger side where it says "2.7l eta" on the block ??

i thought all m20 blocks had 2.5/2.7 on them since its the same block only the internals are different

[ZinRot325i]

That's what mine says. Same with the head.

2.5/2.7

Which is true, since it's a stroker. :-D

[blueapplesoda]

i know my head is a 731 head, but what does this on the block mean?



the x's are because i cant see it in the pic and i can't remember because im currently not at where my motors at.

[nefarious7907]

That cant be right
Mines 1-0-0-0-2-2-6

Its not an M10, its and M20b27
I doubt its the 000 engine ever made
2 it is possible that it was made in munich
26th thats possible my car's birhtday is 12 December, 1983

[T3HCH1LL5]

The engine is your heart, good write up

[Camper Van Someren]

Any idea why certain blocks would not have this stamped in? My car has a replacement engine installed before I got it and I want to know the manufacture date. Unfortunately there is no machined area there and no stamped number: