BMW M3 Forum
BMW M3 Forum BMW M3 Gallery BMW M3 Reviews BMW M3 Social Groups BMW M3 Chat M3Forum Sponsors >>
Loading


Mobile M3forum
Go Back   BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X) > BMW M3 Discussions > E90 M3 (Sedan) | E92 M3 (Coupe) | E93 M3 (Convertible) (2008-2013)
Tire Rack Buy Winter Tires Now!
Not a member? Register Now!
Register Gallery All Albums Garage Search Today's Posts Mark Forums Read Calendar FAQ

E90 M3 (Sedan) | E92 M3 (Coupe) | E93 M3 (Convertible) (2008-2013) {Engine: S65 - Max Hp: 414 hp (420 hp Euro) at 8,300 rpm / 295 lb/ft at 3,900 rpm}


 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old Mon, Jan-02-2017, 09:16:34 PM   #23
PencilGeek
2008 M3 - Red
 
Join Date: May 2008
Posts: 846
Reputation: 0 PencilGeek is on a distinguished road

United States




Default Re: New m3 and rod bearings

Quote:
Originally Posted by Rez View Post
Assuming that majority of cars with original BMW bearing won't fail, almost all the bearings removed looked "bad". The question was asked because the original bearings are largely being judged by their appearance, excessive wear. It is not clear if any of the bearings that were replaced were distant to fail, it is mainly an assumption.
Many bearings that have been replaced have been deemed on the verge of imminent failure. Beatings that are wiped all 180 degrees down to copper are on the verge of imminent failure. There's been plenty of these seen.

Quote:
It is nice to look at the graphs and analysis that you provided but the ultimate proof is cars with BE bearings showing statistically less failure than original ones. I am also curious to see how they look compared with original ones after similar mileage of driving.
It will take a few years before anything like this will be available.

Quote:
Originally Posted by Rez View Post
Why would you think BMW did not do what you have done with all their resources and reputation on the line? Why would they spec the bearings so tight for it to fail on their super expensive engines?
I believe BMW bought into a bunch of politically correct engine designing philosophies. Tighter clearances are known to make the engine quieter, and known to get slightly better gas mileage. Given idiotic government meddling and micromanaging in the auto industry, if you were BMW and about to introduce a very low gas mileage, high strung, naturally aspirated V10/V8, you might be willing to do anything you can to mitigate the political backlash from the EU snobs and American EPA. But in the process of going this direction, BMW chose a clearance that is far under industry recommendations and best practices. Long established engine designs, and those recommended by Clevite themselves, are to use 0.001 inch clearance per rod-journal inch diameter. BMW chose roughtly 70% that value (0.00071). Some engines have been disassembled and measured at less than 60% that value. Most engine builders consider that dangerously too little clearance.

To your second question: why didn't BMW do what we did? I personally believe they would be slapped with a class action lawsuit the moment they changed the design to "fix" it. If they quietly changed the clearance to industry accepted best practices, everybody that doesn't have those bearings will now demand them. A class action lawsuit would be launched almost immediately IMO. It's probably cheaper for BMW to wait out the warranty claims, replace engines under good will, than to go through a class action lawsuit, lose, and issue a recall for 65000 engines. So it's pure business economics why BMW wouldn't do it IMO.
__________________
Jump to top PencilGeek is offline   Reply With Quote
 

Bookmarks

Tags
rod bearings

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT. The time now is 10:04:29 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
M3Forum.com and M3forum.net is in no way sponsored, endorsed or affiliated by or with BMW NA / BMW AG or any of it's subsidiaries or vendors.
BMW and M3 (E90 M3 | E92 M3 | E93 M3 | E46 M3 | E36 M3 | E30 M3) are registered trademarks of BMW AG.
M3Forum Terms of Service
Copyright ©1999-2017 M3Forum.com
Discussing New m3 and rod bearings in the E90 M3 (Sedan) | E92 M3 (Coupe) | E93 M3 (Convertible) (2008-2013) Forum - {Engine: S65 - Max Hp: 414 hp (420 hp Euro) at 8,300 rpm / 295 lb/ft at 3,900 rpm} at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)