Blue numbers on the head, anyone know what they are?

[6speedS54]

I saw some blue digits on the head when I was replacing my clutch, there is also a blue date on the valve cover. Anyone seen this and know what it is?

Thanks

[Estoril]

I did a search:


The blue numbers on a BMW S54 engine's cylinder head indicate the camshaft bearing shell thickness used during factory assembly
. These numbers correspond to specific color-coded bearing shells that determine the clearance for the camshafts.


How the numbers and colors are used

• Factory-determined clearance: At the factory, BMW measured the bearing journals on the camshafts and the corresponding bore in the cylinder head.
• Color-coded shells: Based on those measurements, technicians installed specific thickness bearing shells, each identified by a color and a corresponding number.
• Numbers on the head: The blue numbers on the cylinder head identify the combination of bearing shells required for each camshaft journal. These numbers allow for correct reassembly if the camshafts are ever removed.

Importance for engine work


If you are performing work on the cylinder head, particularly when replacing the camshafts or bearing caps, these markings are critical. You should reference the correct procedure in the official BMW workshop manual or a reliable source to ensure that you use the correct replacement bearing shells. Using the wrong shells could result in incorrect camshaft clearance, leading to premature wear or engine damage.

[Slideways]

Engine might have been replaced at some point. Those pens are sometimes used by resellers to mark a part that they pull from part-out. Can't think of anyone else who would mark the back of the cylinder head like that. Definitely not factory IMO.

[6speedS54]

Engine might have been replaced at some point. Those pens are sometimes used by resellers to mark a part that they pull from part-out. Can't think of anyone else who would mark the back of the cylinder head like that. Definitely not factory IMO.

anyway to find out what engine serial number came with the car?

[Slideways]

anyway to find out what engine serial number came with the car?

The serial number in on the block on the passenger side.

How many miles are on the car? 108,512 could indicate mileage of the engine when it was pulled.

[6speedS54]

The serial number in on the block on the passenger side.

How many miles are on the car? 108,512 could indicate mileage of the engine when it was pulled.

Currently, 124K or so. I meant any way to find out what engine serial number came with the VIN originally

[Slideways]

Currently, 124K or so. I meant any way to find out what engine serial number came with the VIN originally

Only BMW has that info. The white label on the back of the block does have a date code on the bottom right hand corner. Depending on what year your car is, that could tell you if the engine is original or not.

[George Hill]

Those aren't factory markings that I have ever seen.

[sapote]

I did a search:


The blue numbers on a BMW S54 engine's cylinder head indicate the camshaft bearing shell thickness used during factory assembly
. These numbers correspond to specific color-coded bearing shells that determine the clearance for the camshafts.


How the numbers and colors are used

• Factory-determined clearance: At the factory, BMW measured the bearing journals on the camshafts and the corresponding bore in the cylinder head.
• Color-coded shells: Based on those measurements, technicians installed specific thickness bearing shells, each identified by a color and a corresponding number.
• Numbers on the head: The blue numbers on the cylinder head identify the combination of bearing shells required for each camshaft journal. These numbers allow for correct reassembly if the camshafts are ever removed.

Importance for engine work


If you are performing work on the cylinder head, particularly when replacing the camshafts or bearing caps, these markings are critical. You should reference the correct procedure in the official BMW workshop manual or a reliable source to ensure that you use the correct replacement bearing shells. Using the wrong shells could result in incorrect camshaft clearance, leading to premature wear or engine damage.

Do BMW ever use cam bearing shells?

[BCEXP]

I've never seen numbers written on an S54 like that. Definitely not on the valve cover. Looks like a paint pen. Probably a used engine that was swapped in and those markings are ID markings from the parts warehouse.