Quote:
Originally Posted by 1love
It is truism up to a limit. You cannot simply discount real measurements that might indicate your process is out of control, or that there is a variable that wasn't adequately accounted for post-production.
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No, it is a truism, tolerance stacking and a resulting potential for that to be a consequential design/performance issue exist in every assembly in every device in every industry. Here there is absolutely no baseline about crankshaft rod journal standard deviations nor more importantly those vs. longevity. The latter would be significantly stronger evidence than the former. In this particular case the standard deviation of the rod journals is 1/10th of one thousandth of an inch. Is that small or large, small or large compared to what. Again, there is NO "yardstick". I'm sure there are some, but they have not been discussed here.
Quote:
Originally Posted by 1love
Anyway, I think at this point I want to see how the new design performs once released.
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Fully agree, the proof is always "in the pudding". However, it will take well more than 1 or 2 engines to constitute proof.
I'm highly amused by the recent (highly negative) updates on coated bearings. There was outright joy, enthusiasm and near worship for such a wonderful solution for this problem when they first became available. And although I've not seen the data, nor heard that there is much of it, it seems clear that this solution, just ain't a solution. And of course, yours truly held this opinion early that reduced clearances were a bad idea and that the vendors providing these parts/services (treated or coated bearings) provided not a single iota of data/proof that they had a solution (or even a minor improvement).