Quote:
Originally Posted by Billfitz
Here's an interesting fact that doesn't seem to have been pointed out before: The N20 and N55 use the same timing chain. They have since 2004. They use the same slide rail as well. They don't use the same guide rails and tensioner. The N20 guide rail has not been changed since 2011. While the chain was superseded in 2015 it was superseded on both the N20 and N55 It may be more durable than the previous version, but since the N55 has used the same chain all along as the N20 and the N55 hasn't had timing chain problems I doubt that the chain is the problem, at least not in and of itself. The only component that would seem to check off all the boxes, not used in both the N20 and N55 and superseded after 2015, is the tensioner. The new tensioner is known to be different than the old tensioner. Putting two and two together to get four IMO the tensioner was the problem all along.
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Very interesting observation Bill. It would be interesting to compare the spring force of the N54/55 tensioner(s?) to that of the N20 tensioners. And if the N20 1st gen tensioner is indeed the weak outlier, then it begs the question - why would they screw with a proven design like that?
But regardless - hoping this means that the N54/55 history has proven the chain can take a stiffer tensioner than what they first put in, and that I can look forward to another ~100k mi or more before the chain needs replacement again!
