Interesting FCP Euro statement on BMW 0w-20

[kschachn]

Yep, if anything, it improved BMW reliability. We’ve gone from S65 eating rod bearings with 10W-60 to coated bearings and 0W-30 in S58 (0W-20 / 12 in B58 TU2) with more power and fewer issues.

It's not easy trying to correct a gross design error with an oil.

 

[chris719]

It's not easy trying to correct a gross design error with an oil.

Yep. It feels like the pressure to move to such thin oils has finally made BMW properly consider the bearing design.

I do wonder though, let’s say you do have one of these flawed engines. What is the best band-aid? It’s clear that a high HTHS oil alone isn’t solving it because Castrol TWS is pretty stout in that regard. One would have to assume the rod bearings aren’t operating in the hydrodynamic regime all the time. The question would be, what’s the best additive package for this bearing wear? It doesn’t appear to be from cavitation, just accelerated normal wear. The overall answer is that it’s probably impossible to fix this with any oil, but you would think some are better than others.

 

[BMWTurboDzl]

Yep. It feels like the pressure to move to such thin oils has finally made BMW properly consider the bearing design.

I do wonder though, let’s say you do have one of these flawed engines. What is the best band-aid? It’s clear that a high HTHS oil alone isn’t solving it because Castrol TWS is pretty stout in that regard. One would have to assume the rod bearings aren’t operating in the hydrodynamic regime all the time. The question would be, what’s the best additive package for this bearing wear? It doesn’t appear to be from cavitation, just accelerated normal wear. The overall answer is that it’s probably impossible to fix this with any oil, but you would think some are better than others.

Scuttlebutt is that there simply was not enough clearance on the stock bearings and things get weird when you go over 100 hp/liter of displacement. Solution is to use bearings which a little more clearance and shear stable Xw-50w/60w

 

[chris719]

Scuttlebutt is that there simply was not enough clearance on the stock bearings and things get weird when you go over 100 hp/liter of displacement. Solution is to use bearings which a little more clearance and shear stable Xw-50w/60w

The issue isn’t simply clearance though it was a contributor. Even the BE bearings show what would be considered accelerated wear for most other engines. Good point on the shear stability.