Quote:
Originally Posted by Ilvez
Chris and Tom, do you have a clue why N54 engine has crank hub central bolt final torque requirements of 360 degrees and S55 270 degrees? The central bolt appears to be the same:
http://www.realoem.com/bmw/enUS/part...&q=11217614270
Why not torque S55 crank bolt could as well extra 90 degrees, giving some additional assurance on top of CBC + splined hub (or for whatever hub in question)?
As far as I have read technical docs, Gintani requires 325ft/lbs on their keyed setup, which would be interesting to compare to OEM torque requirements.
Anyway, the takeaway so far seems that there are no reports of VTT Spline Lock + CBC combos slipping even on very highly tuned and abused S55 engines, which is very good news. As long as clients are seriously advised only to use VTT spline lock together with CBC  |
You bring up an interesting point, will look into this further. Gintani provides their own replacement crank bolt on their kit.
Quote:
Originally Posted by cntzl
What's more interesting to me is that there are no cases of failure in the presence of CBC (with or without the spline lock hub). Kinda makes me think that CBC is the key component here, even more so than the spline lock hub. Is there still a chance of slipping with just the CBC? Probably but I'm still concerned about the case of failure with both spline lock hub and the CBC installed. In that case, splines will leave a permanent damage on the crank and you probably cannot just go ahead and simply install another hub (splined or keyed). Again, I have bought the whole kit but at this point I'm more inclined towards installing the CBC only.
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VTT released the SpineLock/CBC on Nov 18, A ~4 month window is simply too short to base any facts on.
Installing the CBC without the SplineLock hub doesn't really put you in any safer territory. It's been recommended multiple times to install both pieces to eliminate any variables, rather than looking at a SCH in hindsight and wishing you did if your M2C is a keeper in the long run.
In the end, it's purely your decision, just don't become a statistic.