[ProjektAutoScott]

This info has proven extremely useful to our customers, so I'd like to share it here. Seems like many repair shops and engine builders aren't super public about any of this.

This is based on hands-on experience with repairing, dismantling, and selling many N63 and S63 tu and non-tu engines. I am well aware of the various part numbers and what realOEM and other catalogs say and don't say. This is based on what is actually seen and tested.

Historically, BMW intends to sell complete engines. Part numbers are buried, fitment is incomplete or broken, changes and revisions aren't clear, and in a lot of cases the only thing you’ll find listed is a complete assembly (e.g. F85 X5 M when you need a new block, your only official option is to buy a complete engine).

Cylinder head castings aren’t sold separately. Blocks aren't sold bare or aren't sold at all. Replacement engines have completely unknown internals (usually a hodgepodge of whatever BMW is currently producing, or whatever is overstock)

I'm sure there are many "official" reasons for all of this. It might not just be a blatant money grab or a means of creating obscurity to preserve the cost and reputation of certain models meant to be unique...

Here is what we have learned over the years:

BLOCKS

Version 1 – Early 2011 and prior
Found in early N63 and S63 cars. These have the conjoined piston oil squirters: four total, one for every pair of cylinders. This block only supports the version 1 connecting rods, as pointed out below. The later style rod caps will collide with the oil squirters. There isn’t a simple fix for this.

Version 2a – Early 2011 and later
Found in N63, S63, N63TU, and F85 S63TU applications. These have individual piston oil squirters: eight total, one per cylinder. Otherwise the block is the same as Version 1. All interchangeable.

Version 2b – F10 M5/M6 only
Unique to S63TU engines in the F10 M5/M6. This version has an un-drilled oil galley and requires its own oil pump and upper pan. The block/pan/pump combo is specific to the F10 M5/M6. It still has eight individual squirters. A Version 2a block could possibly be used in a pinch if you machined and installed a blocking plug.

Despite what the S63/N63 engraving on the block says, there is nothing inherently special about any of these blocks. An F85 X5M block is the same casting you’d find in an E70 50i. The engine code engraved on the block identifies the long block assembly after assembly, not the bare block itself. The actual 7 digit part numbers for the blocks themselves are not publicly organized in any catalog. You'll see many factory S63 engines with a big old "N63" casting number on the back of the block. (e.g. N63, N63/4, N63/5, N63/12, etc.). This doesn't mean you got scammed on your engine.

CYLINDER HEADS

Version 1 – N63 non-TU
No Valvetronic.

Version 2 – S63 non-TU
No Valvetronic. Made from a higher-grade alloy. Has a different bolt pattern for the S63 exhaust manifold and an S63-specific exhaust cam.

Version 3 – N63TU and S63TU
Valvetronic. Same castings, same cams, same everything. S63TU heads don’t come with exhaust manifold studs installed. All versions interchange within the TU family. Only odd thing I’ve noticed on some TUs: the valvetronic intermediate lever rollers ride on machined support blocks. Some TU heads have single-bolt support blocks while other heads have double-bolt support blocks. I am guessing the double-bolt was an update made at some point. Either style is fine, and you can mix and match complete heads if you had to. I can’t find production dates to tie this to yet.

Non-TU valve covers swap between N63 and S63. TU valve covers swap between N63TU and S63TU.

CRANKSHAFTS

Version 1 – Early 2011 and prior
Found in early N63 and S63 engines. Typically stamped with alloy/heat-treat marks like “C38mod.”

Version 2 – Early 2011 and later
Found in N63, N63TU, S63, and S63TU. Stamped with something like “C38 N2.” This is allegedly a stronger crank. It appears again in later N63TU2 and S63TU2 engines as well, but we don't know a ton about those engines yet.

Physically, either crank will fit almost any N63/S63 engine. That doesn’t mean you should replace a Version 2 with a Version 1. The early cranks may be weaker or have a less robust heat treat, even though the dimensions are the same.

CONNECTING RODS

Version 1 – Early 2011 and prior
Found in early N63 and S63 engines. These use an angled split rod cap for bolt clearance around the early-style piston squirters.

Version 2 – Early 2011 and later
Found in N63, N63TU, S63, and S63TU engines. Straight split cap. The rod bolts need more clearance, which is why BMW switched to the individual oil squirters in the updated blocks. These use a different upper bearing shell (the locating tab is flipped) and different rod bolts.

Version 1 rods work in any block. Version 2 rods only work in the later-style blocks. Some claim Version 2 is stronger.

PISTONS

Each of the four engines uses its own piston design. Basically the same from SOP to EOP. All N63 engines share one piston, all N63TU share another, and the same goes for S63 and S63TU.

Wrist pin diameter is the same across everything, but the pins themselves are specific to each piston. BMW does not sell the pins separately as far as we can tell.

Real-World examples if you have time on your hands:

If your F85 X5M blows an engine, you can buy a cheap used N63TU and swap the pistons.
If your E70 X5 M scores a cylinder, buy a block from a 550i.
If your F10 M5 spins a bearing, you can use a crank from an old 750i.
If you’re shopping for an E70 X5 M or X5 50i, it’s worth finding one built after 03/2011 just for the later internals.

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As these cars get cheaper and cheaper, owners should know they have options besides buying a brand-new $35,000 long block for a 15-year-old vehicle with 120k miles.

In reality, BMW reused and evolved a ton of N63/S63 components over the years. Late non-TU engines have TU parts in them. Some pieces carry all the way forward into 2025-era engines.

Happy to hear from anyone who has handled a head, piston, rod, or block that contradicts any of this. Feel free to post photos or ask questions. I can also post photos of any differences you are interested in seeing.

[thedrinkwater]

This is great info!

Only note I have is that the early (pre-~3/2011) block is not notched for the post-~3/2011 connecting rods (you do mention this in the connecting rod section, but not in the block section).

I suppose if someone really wanted to, they could cut the notches in an early block to fit the post-3/2011 connecting rods.

Also interesting to know that the crankshaft changed after 3/2011.

I was surprised to see how many changes BMW made to the n63 in 2011.

[xVoidx]

Great info thanks. Also I cant seem to send a pm and I need one of the 90 degree turbo coolant line fitting you are offering for adding the gamma lines to my m5. Any help?

[ProjektAutoScott]

Originally Posted by thedrinkwater

This is great info!

Only note I have is that the early (pre-~3/2011) block is not notched for the post-~3/2011 connecting rods (you do mention this in the connecting rod section, but not in the block section).

I suppose if someone really wanted to, they could cut the notches in an early block to fit the post-3/2011 connecting rods.

Also interesting to know that the crankshaft changed after 3/2011.

I was surprised to see how many changes BMW made to the n63 in 2011.

That’s worth pointing out for sure.