S54 rod bearing
- Thread starter Vanne
- Start date
bmwaddict said:
While the bottom end is dropped worth having the engine mounts replaced and engine mount bolts (the 4 on either side connecting the mount to the engine block) checked as these tend to back out. Also worth asking Phil to check the vanos, suspension, rear trailing arm bush, front control arm bush, brake calipers, exhaust clamp (these can that and break) and anything else. Although these probably aren't so urgent.
I suppose this is THE rodbearing-thread so I should put mine up here aswell...
Relieved they could not find a single scoring mark or scratch on the crank surfaces.
Mine's a 2006, 178926km (111179miles) car.
Bought it at 154000km's, so I don't know the details of that distance other than it's been well serviced at BMW according to the service stamps/receipts.
During my time i've done 4 trackdays in total.
Paid 16177kr for the job (about 1463£)
In no particular order (got all in a bag):
Will run in for c:a 1200miles under 4000rpm.
Workshop (Bo&Jimmy's in Gothenburg, Sweden) claim I don't need to change oil after that but advise oil change each 10000km's maximum (which I always done anyway).
Relieved they could not find a single scoring mark or scratch on the crank surfaces.
Mine's a 2006, 178926km (111179miles) car.
Bought it at 154000km's, so I don't know the details of that distance other than it's been well serviced at BMW according to the service stamps/receipts.
During my time i've done 4 trackdays in total.
Paid 16177kr for the job (about 1463£)
In no particular order (got all in a bag):
Will run in for c:a 1200miles under 4000rpm.
Workshop (Bo&Jimmy's in Gothenburg, Sweden) claim I don't need to change oil after that but advise oil change each 10000km's maximum (which I always done anyway).
These are my rodbearings on a supercharged M54B30 at 150.000km (from which roughly 45.000km supercharged)
Only the last bearing (cyl6) has some irregular wear which happened very slowly because the wearspot is very smooth and shiney.
The only reason I could think of is that that is the result of increasing the torque from 300Nm (stock) to 465Nm, and that that extra toque flexes the crank ever so slightly at the end (where the torque is highest)
I have no idea why the s54 has so much trouble with the bearings. It isnt the power/torque (as my bearings look much better and endure more torque/power and are smaller) so I think its that the high revs and longer stroke (so the crank swings more from left to right) cause cavitation in the oil passage. And cavitation erodes like hell (look at speedboat engine propellors)
Only the last bearing (cyl6) has some irregular wear which happened very slowly because the wearspot is very smooth and shiney.
The only reason I could think of is that that is the result of increasing the torque from 300Nm (stock) to 465Nm, and that that extra toque flexes the crank ever so slightly at the end (where the torque is highest)
I have no idea why the s54 has so much trouble with the bearings. It isnt the power/torque (as my bearings look much better and endure more torque/power and are smaller) so I think its that the high revs and longer stroke (so the crank swings more from left to right) cause cavitation in the oil passage. And cavitation erodes like hell (look at speedboat engine propellors)
Thanx Guido, I'll ask the workshop if they did measure the crank.
It does have a ever-so-slight rattling noise on warm tick-over, only heard from inside the car with doors closed. I THINK it wasn't there before but I hope I'm mistaken.. New shells (less play) certainly should make it LESS noisy if anything so it may be something else.
It does have a ever-so-slight rattling noise on warm tick-over, only heard from inside the car with doors closed. I THINK it wasn't there before but I hope I'm mistaken.. New shells (less play) certainly should make it LESS noisy if anything so it may be something else.
Usually bearing rattle ('conrod knock') is heard in the engine bay and increases in loudness at higher revs and is sometimes absent at idle.
If you hear it mostly at idle, it's something else.
Usually when you swap rod bearings all bearings should be plastigauged.
With bearings worn like this its important to closely inspect the crank on scoring marks.
As you can see on my picture I also plastigauged the old bearings. Mostly because nobody does that. All bearings were still in tact and hardly any wear so they measured up well within BMW spec.
If you hear it mostly at idle, it's something else.
Usually when you swap rod bearings all bearings should be plastigauged.
With bearings worn like this its important to closely inspect the crank on scoring marks.
As you can see on my picture I also plastigauged the old bearings. Mostly because nobody does that. All bearings were still in tact and hardly any wear so they measured up well within BMW spec.
Just updated all the Photobucket 
pics from the beginning of the thread, could I ask others to do the same please, as hopefully more and more peeps will add their details.
Thanks.
V.
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Howly cows Batman!!
! those are well and truly shot! 
Glad you caught it in time.
pics from the beginning of the thread, could I ask others to do the same please, as hopefully more and more peeps will add their details. Thanks.
V.
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Argenta said:
Howly cows Batman!!
! those are well and truly shot! Glad you caught it in time.