Some of the failures have been with Phils own installations, not just those done by customers or other installers. I think that ensuring a correct fit of the spline adaptor to the relatively soft and not amazingly uniform crank splines is a problem. Not sure how this will be overcome but I expect Phil is onto it.
My installation was done by Phil some time ago and has been faultless in the 12,000 plus miles I have covered since, others have not been so fortunate. I have used the Centa rollers for all but the first 1500 miles as I find them a bit less harsh under hard acceleration than Phils inserts, this may have some bearing on the lack of problems I have had? I also had the retaining nut wire locked on assembly to ensure it couldn't move. I believe in belt and braces.....along with some "fence wire" for inaccessible nuts, although the nut coming loose is not the issue I am told. I am at a loss to understand how (on the failed modified Centa drives) the Centa body can be rotated by hand on the splines if the nut remains fully torqued and the adaptor is fully bottomed out against the crank flange, as has been reported. If the wire locking is broken, you 100% know the nut has moved.
I would still recommend Phils Centa mods, it's a much improved design but the spline adaptor is not just a "bolt it up" installation, maybe some very careful fitting and locking is required? I don't know what the answer is but I hope it is fixed soon as it is a concern if you are doing some miles.
