[itscinematic]

I have 2 S54 cam shafts. In theory, one should be for intake and one should be for exhaust. However, there is no label indicating which would be for which. The only difference I can find is that one has a two “2” on it and one has a three “3” on it. however, there is no BMW documentation or anything anywhere that would suggest that those numbers could indicate which is which.

 

[SloopJohnB]

I have 2 S54 cam shafts. In theory, one should be for intake and one should be for exhaust. However, there is no label indicating which would be for which. The only difference I can find is that one has a two “2” on it and one has a three “3” on it. however, there is no BMW documentation or anything anywhere that would suggest that those numbers could indicate which is which.

first thing check realoem. There should be a p/n on the camshaft somewhere.

01	Inlet camshaft		1	04/2003		11317833223	$952.40
02	Camshaft exhaust		1	04/2003		11317833225	$744.25

 

[Michal_]

Not sure about S54, but M54 camshafts have clear A (exhaust) and E (intake) marks at the end. See on the following picture:

 

[itscinematic]

They don't have any kind of part number that seems to match up with any BMW part number, and they don't have an A or an E, but they do have something that I'm surprised no one here has mentioned.

From this website "The intake camshaft impulse wheel has 6 lugs and the exhaust camshaft impulse wheel has 7 lugs (with gap)."

 

[SloopJohnB]

They don't have any kind of part number that seems to match up with any BMW part number, and they don't have an A or an E, but they do have something that I'm surprised no one here has mentioned.

From this website "The intake camshaft impulse wheel has 6 lugs and the exhaust camshaft impulse wheel has 7 lugs (with gap)."

Interesting...the realoem website also shows 6/7 lobe impulse wheels and different p/ns for the camshafts. I checked with ECS Tuning and the tech there says they don't know how to differentiate the two camshafts..puzzled him too. #3 cited website even stated
The camshafts are not interchangeable, therefore they should be marked before disassembly.
At this point only thing I could suggest would be a degree-wheel setup to measure lobe timing and compare with OEM valve timing specs (wherever you find them is yet another mystery). The lobe lifts are same at 12mm AFAIK so can't be used to differentiate cams.