I'm sure others can come in & suggest things, but I'd pull a spark plug & measure the Stroke of the crank. Then you'll really know.

325 = 75mm / 2.95"

330 = 89.6mm / 3.53"



Good luck,
Rob43

 

The 323 had the M52 a cast iron block in 2000, the 325 in 2004 had the M54 with an aluminum block. The 330 also has the M54, so you still don't know which you have, 2.5L or 3.0L. Removing a spark plug and setting a long rod into the hole, then marking the distance from the highest point to the lowest point will tell you the stroke, which is a round about way of arriving at the displacement.

If Rob43 is right, then the difference in the 325 and the 330 is about 1/2 inch.

Set a straight edge and mark the rod when the piston is all of the way up or down. Then turn the crank by hand and mark the rod again at the other end of the stroke. Measure the distance between the marks. If the distance is 3 inches then you have the 325, if 3.5 inches then you have the 330.

 

The 323 had the M52 a cast iron block in 2000, the 325 in 2004 had the M54 with an aluminum block.

The E46 323i and 328i have M52TU engines, which have an aluminum block just like the M54.
The E36 BMWs were equipped with the M52 engine, but they were out of production by 2000.

 

Instead of removing a spark plug and measuring stroke, you could also measure throttle body diameter. The M54B30 out of a 330i will have an 80mm throttle body vs the 63mm of the other engines.

 

i just commented in a similar thread today about the same topic.

I came across a neat publication from BMW, titled "Introduction to BMW". I found it at the following site: http://www.kneb.net/bmw/Intro to BMW.pdf.

On pages 37-42 they explain naming conventions for BMW engines and also document where the powerplant identification plate is found on most BMW engines. By examining the powerplant stamp, you should be able to quickly determine which engine you have. Be warned, you may need a lift and a really good flashlight to see the engine stamp!

 

When I was trying to figure out if a bike I had was a specific model, either the steel or the aluminum version, I asked a similar question. The answer was too simple--use a magnet. The same might help you out to determine if your block is aluminum or cast iron.

 

Thanks guys. I'm new here and I really appreciate the help

 

Where is the serial number on the block? And I looked up some images from google. I think it is an M54 due to the placement of the oil fill cap.

 

http://forum.e46fanatics.com/showthread.php?t=729353&highlight=engine+block+serial+number

 

Purple fuel injectors on 3.0, at least in some.

DISA valves for 3.0's are taller, internally, than 2.5's. Not too much trouble to pull. You'll have to go to ECSTuning and look at their images to compare.