Quote:
Originally Posted by gmd2003
But the engineers never intended for the S54 to rev to 8000 rpm, thus the S54 in the Z3M roadster has a 7800 rpm limit. In the US we had a massive recall after multiple cars spun bearings on the 5-30. BMW revised the bearing material and then made the Castrol 10-60 the required oil. You are correct about the 10-60 being based off of a 0-40 though , it actually has a lower viscosity after one track day than the Motul 15-50 does after several.It breaks down rapidly. My concern with you using 0-40 in a hot climate is that your bearing wear was from spirited driving not the 10-60. You needed more film strength at the bearing surface not less.
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I actually know the story differently, the rod bearings were due to a rod design issue.
The oil 5w-30 was replaced due to S54 burning a lot of it before the next oil change and the maintenance interval was set at an aggressive 15000 miles.
I agree with you that a 5w-30 oil will cause problems but a mobil1 0w40 probably is better than the original 10w-60
I am grey on this whole subject so i cant reinforce my ideas further. I will maybe try to find an oil analysis to see how the 0w-40 is holding up.