Quote:
Originally Posted by GuidoK
Are you sure that's wise? the bearing clearance on the s54 rodbearings is considerably larger than on say a m54.
10W40 is also an oil weight that is used by a lot of people that have a m54b30.
Although it's difficult to say which engine runs hotter. The s54 takes longer to heat up evenly (cast iron block) but also has an oil cooler with thermostat.
I think in the end rodbearings are just a part of life for the s54/65/85 owner. Calculated costs for high revving undersquare engines.
|
According to BMW TIS the crankshaft bearing clearances are similar, they're actually slightly tigher on the S54. But the con rod bearing clearances are a little looser on the S54, but not a lot. Depending on the clearances I would run 10W-40 (lower end clearances) or 5W-50 (higher end clearances). But that's just my opinion.
S54:
https://www.newtis.info/tisv2/a/en/e...arings/5rYXcUH
https://www.newtis.info/tisv2/a/en/e...arings/5wRWhGB
M54:
https://www.newtis.info/tisv2/a/en/e...arings/6zJ8es4
https://www.newtis.info/tisv2/a/en/e...arings/79Vl9k3
My S54 in the E46 M3 doesn't have an oil thermostat nor does it run hot. On a track day during summer the oil never reaches over 100 degree and the water stays below 90 degrees, always. But I do agree that the rod bearings should be considered a service item on a S-engine.
Edit: And if you compare to a newer engine like the N55 in the M2, the con rod play is even larger than the S54 and the recommended oil weight is 0W-30 to 5W-40.