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      01-11-2014, 09:13 PM   #1884
///mawana's Avatar

Drives: e90 M3
Join Date: Sep 2013
Location: Little Elm, TX

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Originally Posted by catpat8000 View Post
Guys, you need to be pretty careful on how you use this data. While I appreciate SFP working to get more data, let's examine what he has obtained.

The list of cars is at 30. Of those, 6 were supercharged. 4 of the engines had valve issues, not rod bearing issues. 7 (probably more - some FI cars weren't clearly identified) of the cars had tunes. 1 car had a failed oil pump.

So if we factor out extenuating circumstances, and we assume the best case for missing data, we are left with this:

17 cars failed:
- 6 2008 models
- 2 2009 models
- 1 2010 model
- 6 2011 models
- 2 2012 models

As many have pointed out, 2011 cars often had build dates in 2010. My own M3 has a build date of April 2010 and it is a 2011 model.

So assuming that there is some statistical significance in this smallish amount of data, it does not conflict with the notion that the new bearings reduced the odds of an engine failure.

Originally Posted by SenorFunkyPants View Post
I did the same with my latest Excel file and I got something a little different.
19 cars failed:
- 6 2008 models
- 1 2009 models
- 1 2010 model
- 7 2011 models
- 2 2012 models
- 2 2013 models

I'll keep on it and see what else I can find out....I still have to re-message some of the voters to help fill in the missing fields.
As you say the sample is very small which in itself is very encouraging.
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.

Considering these spikes and troughs I would venture to say if there were to be 2014 models we would witness elevated failures too for that production run. Speculation, I know, but it appears there is a pattern which suggests the problem isn't random but very systematic. Could be something systematically flawed in the M production/assembly line, I don't know, but whatever it is, it is rearing its ugly head every 4th year of production. Perhaps, failure patterns, if any, for the s54 and s85 could help shed some light.

That said, I would like to thank the technical guys who have selflessly partook in this thread, I have really learnt a lot.