Technical Updated N54 Crank Hub Info

[IQraceworks]

I thought this info might come in handy for anyone who’s wanting to install one of the “updated” style crank hubs. The new updated hub has a turned down nose section, and the gears have a smaller inner diameter in order to increase the surface area that seats against the friction discs. I took some measurements on the updated gears and friction discs, and they increased the clamping surface area around 50%. Also, the friction discs now have what appears to be a gritty diamond coating (not sure what it actually is, but it sure feels like the same material that’s on my diamond coated knife sharpening hone plates), instead of the old style friction discs which look like they just have these microscopic rings/grooves formed into them. The new style friction washers definitely feel more “grippy”.

Definitely not a 100% “never going to slip” solution like the pinned or splined crank hubs for $1K, but for under $200, I think this updated crank hub design from BMW is definitely an improvement.

 

[BillV]

I thought this info might come in handy for anyone who’s wanting to install one of the “updated” style crank hubs. The new updated hub has a turned down nose section, and the gears have a smaller inner diameter in order to increase the surface area that seats against the friction discs. I took some measurements on the updated gears and friction discs, and they increased the clamping surface area around 50%. Also, the friction discs now have what appears to be a gritty diamond coating (not sure what it actually is, but it sure feels like the same material that’s on my diamond coated knife sharpening hone plates), instead of the old style friction discs which look like they just have these microscopic rings/grooves formed into them. The new style friction washers definitely feel more “grippy”.

Definitely not a 100% “never going to slip” solution like the pinned or splined crank hubs for $1K, but for under $200, I think this updated crank hub design from BMW is definitely an improvement.



View attachment 91375 Just replaced mine. My hub bolt lost its tension enough that the friction washers weren’t doing anything. And ironically enough, I did see a code pop up, something about ‘crankshaft bolt torque’ and didn’t pay attention to it when I should have. Cams stopped spinning and now I think I’m looking at some bent intake valves.

 

[IQraceworks]

Wow...that's nuts. With the amount of torque that I had to put on that new crank hub bolt, I have no idea how that thing would ever come lose.

Are you going to just try to pull the head off and replace the bent valve(s)?

 

[BillV]

Wow...that's nuts. With the amount of torque that I had to put on that new crank hub bolt, I have no idea how that thing would ever come lose.

Are you going to just try to pull the head off and replace the bent valve(s)?

 

[BillV]

It’s 17 yrs old, 187k miles. I guess it’s worn out.
The new hub went in and yeah, that was some task. A long pipe helps tremendously.
Confirmed bent valves yesterday, took off intake and valves 1&2 weren’t closing. So head coming off is next. Removing the turbos is on deck for the weekend.

 

[IQraceworks]

It’s 17 yrs old, 187k miles. I guess it’s worn out.
The new hub went in and yeah, that was some task. A long pipe helps tremendously.
Confirmed bent valves yesterday, took off intake and valves 1&2 weren’t closing. So head coming off is next. Removing the turbos is on deck for the weekend.

Yeah, getting that bolt torqued down takes some force for sure! Hopefully it didn't cause any other damage, and you can get a new set of valves back in the head and you will be good to go.

 

[jakeg]

It’s 17 yrs old, 187k miles. I guess it’s worn out.
The new hub went in and yeah, that was some task. A long pipe helps tremendously.
Confirmed bent valves yesterday, took off intake and valves 1&2 weren’t closing. So head coming off is next. Removing the turbos is on deck for the weekend.

My 2009 motor with 198k miles failed immediately after I threw a single turbo on it. The new hub design adds more friction material, but still can cause a failure. That crank hub is the same crank hub on the s55, and I would still elect for a mechanically locked crank hub. I've had the Vargas spline lock crank hub and its given me zero problems since install. The cyl 4 rod exited the block this past week so I'm out of the modified n54 platform.

 

[KClemente]

Saw some off brand spline hubs on ebay here. No idea if the hardness of the splines are VTT V2 level but worth a look at least.

 

[jakeg]

Saw some off brand spline hubs on ebay here. No idea if the hardness of the splines are VTT V2 level but worth a look at least.

Interesting that these exist, although I wouldn't risk the motor for a 500$ savings haha

 

[BillV]

My 2009 motor with 198k miles failed immediately after I threw a single turbo on it. The new hub design adds more friction material, but still can cause a failure. That crank hub is the same crank hub on the s55, and I would still elect for a mechanically locked crank hub. I've had the Vargas spline lock crank hub and its given me zero problems since install. The cyl 4 rod exited the block this past week so I'm out of the modified n54 platform.

That sucks.
Damn Bummers.