We now have 30 responses with 15 noisy and 15 quiet
(Ignore the yellow highlight for 105Chris - it simply delineates between quiet and noisy)
Of the 15 noisy:
12 are 2013 or earlier, 2 x 2014 and a 2015 Brooklands
7 have the NVH, 8 do not (assuming hbatts does not.)
Pretty much all the noise is when the BB is hot and somewhere in a 45 – 65 mph speed range
7 are still noisy with heavy duty oil and 6 of the quiet have replacement oil.
Of the 15 quiet:
8 have NVH and 7 do not
8 are 2013 or earlier, 7 2014 or later
Some conclusions so far:
The BB noise appears to be less for current cars.
For those with a noise problem there is no clear advantage in NVH and/or heavy oil (although 2 reports of quiet running with a 140 oil)
The noisy BB is speed and temperature dependent which perhaps points to a resonance and thermal issue (a good post from RogG about the pre loading which makes sense).
See also a previous post from Bwitched about rebuilding his BB which could also point to a preload issue:
http://www.talkmorgan.com/ubbthreads.php/topics/281974/Re:_Bevel_box_rebuild#Post281974
I was sort of hoping this survey would point towards a simple single solution but I don’t think that’s been the case.
I’ll forward it to MMC as a follow-up to the M3W Focus group and, unless any of the respondents object, also copy to Garage 56 to see if it helps their investigations.
