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      01-11-2014, 08:34 PM   #1885
catpat8000
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Quote:
Originally Posted by mawana View Post
The failure sample is thin, but,...

From a data perspective, the 2011 failures are pretty discouraging. They seem to be gravely contradicting the bearing clearance explanation. Even the oil which has remained a constant parameter isn't fully explaining the 2008 and 2011 failures. I guess I was expecting the trend set from 2009/10 to persist had either oil or clearance were problem areas. Yet we have a spike in 2011 then a similar trend for 12/13 to 09/10 ensues.
I wouldn't be so quick to draw the same conclusion (2011 being discouraging) for two reasons.

First, because most 2011 cars were built in 2010 and likely had the old bearings.

Second because the data sample, while a good start, is still too small. Imagine, as an exercise, that we had only one sample: a 2012 car. Would we be justified in saying that only 2012 model years had problems? Or that the bearing changes made things worse after 2011? Nope, in reality the data size is just too small. So you see how small data sets can be extremely vulnerable to noise swings.

What we all ought to keep doing is to funnel all reports of bad engines to SFP who can keep the canonical database and hopefully with more time, we will see more patterns as the data gets larger.

If you have an engine fault, send it to SFP!

Pat
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