TrAcK TRaP wrote If not failed it doesn't count. They pull RB's at 40K miles they say they were going to fail soon and pretty bad wear on them. They say same thing for 60K , 80K , 100K, 120K miles vehicle. People comment on OP's car he just got and right away replace your RB's ASAP. If he wasn't a forum member guess what he would do? Yep leave it alone.. I am not against replacing them don't get me wrong. Even its a %1 or less chance. I have 2 friends who is not a forum member they both have high milage E92's and they don't even know what RB is.They enjoy their car so much and drive pretty hard. I just hate the fact that whoever get an E9X and become a forum member we right away tell them to replace the damn RB's.. Some owners use crazy oils like 0w40 in summer and drive pretty hard some owners brings the RPM about 6-7K when car is cold so these are the stupid mistakes. At the end its owners choice and they can do whatever they wanna do. Ones again I am not against to RB replacement but %90 of forum members will think and say OP's car will have RB failure very soon. If car had 120K miles same thing right? Here is another 50K miles which is another 5-6 years because most owner like to keep them in garage on winter and baby them thats not me. I got an E9X M thats because its NA high revving master piece engine and I am not scared to drive it. No plan for supercharging no plan for RB's or TA (if not failed)..
I would agree with you but there are a couple items that cause me to lean towards the side of caution.
1) The data presented on this Wiki shows that there is a very real risk of having a bearing tolerance that will cause failure.
2) The flow data supplied by BE during testing clearly
shows (does not prove) that bearings with proper clearance have much better flow at high RPM. Better flow equals better cooling and also ensures the hydrodynamic bearing is operating properly. This post nails the fundamental point.
3) The evidence posted on this forum
shows that most bearing pulled from S65 engines are in poor condition for their mileage (mine were actually in very good shape (attached) for an S65 at 19K Miles but they still showed the beginnings of wear which is bad for such a young engine).
4) The cost of replacing an S65 is, at minimum, an order of magnitude more than the parts required to change the bearings with BE hardware and shells. Even including reasonable labor, an engine swap is still significantly more expensive than changing the bearings. Also, if you have to pay to have your bearings changed, then you will probably have to pay to have your engine swapped. (I have the tools to swap bearings - I do not have the tools, knowledge or shop space to swap an S65).
As for the comparison to throttle actuators and bearings: TAs do not have a cost effective preventative maintenance activity. Therefore, they are a run to fail then replace asset. Rod bearings do have a cost effective preventative maintenance activity. Unfortunately, oil analysis has not shown to be reliable in properly identifying when to change the bearings while guaranteeing zero failure risk. In that case, sooner is better than later, and certainly better than after-boom.
Every person on this forum has access to a lot of
data. Every member can also make their own choices based on the
data. Clevite, King, ACL and others all have design guides that show recommended clearance specifications. These can be compared against the
data provided as well as the BMW specified tolerances.
OP - sorry for the thread jack. I hope your swap goes well and that you have many happy years with your new car.
Enjoy your M.
Cheers,