rod bearing solution ? finally?
- Thread starter Beedub
- Start date
basically a larger tolerance to promote better lubrication .
it is believed the cause of the premature worn bearings is too tight tolerance. The 10w60 is great when boiling hot ( track work) but according to the so called pro's its too thick during normal operation to lubricate properly on a day to day basis.
it is believed the cause of the premature worn bearings is too tight tolerance. The 10w60 is great when boiling hot ( track work) but according to the so called pro's its too thick during normal operation to lubricate properly on a day to day basis.
Would moving to a 5w-50 not also help cold start lubrication where the current tighter clearances and thick oil struggle to protect the wearing faces?
It seems to make sense in principal very few stray away from castrol TWS or equivalent retail product.
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It seems to make sense in principal very few stray away from castrol TWS or equivalent retail product.
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Hmmm...
Rod bearing clearance was BMW's answer to failures on the S54.. They altered the sizing and oil weight to try and counteract the high instances of failure at the time.
And it worked to a certain degree, although it didn't fully cure the problem..
There are a few manufacturers that produce custom bearings for "S" derived engines, all claiming similar advantages..
Some other people claim rod bolts stretch, causing the bearing to spin..
IMHO there is commonality in all the "S" engines being that piston crown size is large in relation to rod journal size. This creates a lot of thrust, and with the speed the engine has to rotate to create the power required, high bearing wear is just a natural product of the design..
If you look at the new generation of BMW engines that are turbocharged, with huge torque figures that have no bearing issues, then you have to suspect the fundamental design of the earlier M engines is to blame, and in reality there is no answer to the problem.. The only way to safeguard is to swap out the bearings and wear issues are negated..
Rod bearing wear is not uncommon in high revving race engines,the "S" engines emulate this wear pattern but over a much longer life span..
Rod bearing clearance was BMW's answer to failures on the S54.. They altered the sizing and oil weight to try and counteract the high instances of failure at the time.
And it worked to a certain degree, although it didn't fully cure the problem..
There are a few manufacturers that produce custom bearings for "S" derived engines, all claiming similar advantages..
Some other people claim rod bolts stretch, causing the bearing to spin..
IMHO there is commonality in all the "S" engines being that piston crown size is large in relation to rod journal size. This creates a lot of thrust, and with the speed the engine has to rotate to create the power required, high bearing wear is just a natural product of the design..
If you look at the new generation of BMW engines that are turbocharged, with huge torque figures that have no bearing issues, then you have to suspect the fundamental design of the earlier M engines is to blame, and in reality there is no answer to the problem.. The only way to safeguard is to swap out the bearings and wear issues are negated..
Rod bearing wear is not uncommon in high revving race engines,the "S" engines emulate this wear pattern but over a much longer life span..
Smartbear said:
When the problem of bearing shell failure first occurred in the S54 engine fitted to the early E46 M3s, BMW limited the engine revs to 7,600rpm fitted to the same S54 engine fitted in the Z3 MC/R. BMW claimed that BS failure couldn't occur at such lowered revs but I know of at least 8 reported BS failures on forums related to less than 200 Z3MC/Rs in the UK, including my own.
As has been said, I think BS wear is just a fact of life with such a performance engine that needs to rev to achieve its power.
