S54 rod bearing
- Thread starter Vanne
- Start date
mr wilks said:exdos said:srhutch said:
You'll bethen you'll hear it banging
Whooooo that's not good
So are there major differences in the design or components from a 06 ZM S54 to 08 S54 & if so when were the changes implemented ?
I think the important changes in question were before 2006 so all Z4M have the latest components in that respect.
John, I think you misunderstood me - I was referring to the use of revised components in the later S54 engines as likely being responsible for the marked reduction in reported BS failure in all platforms. That's why I separated the vehicles using the S54 into two cohorts - those with the original iteration of the S54 (the ///M Coupe, ///M Roadster and early E46 M3) and those with the revised engine (the later E46 M3 and the Z4M). If you look at the reported incidence of BS failure in the E46 M3 this fell markedly in those vehicles produced after the use of the revised components commenced. Had your ///M Coupe had this revised engine (as it most probably now has), you would have been extremely unfortunate to have encountered the problem. Of course, high mileage wear in a later engine with revised components is a very different mode of failure and I suspect it is this the OP has encountered.
Richard, I'm just trying to explore the cause of BS failure. 
When this problem first appeared in the earliest E46M3s, BMW blamed the owners! Then it did a few panic band-aid fixes until it properly understood the problem and came up with the revised parts in its later engines. The incidence of bearing shell failure has been considerably reduced, but it will still occur in an engine of this type. Wear of bearing shells, particularly with high mileage and a fair amount of use at high rpm, is normal.
The piston speed of the S54 engine is one of the highest seen in a production car, and although I'm no expert on these matters, it seems logical to me to believe that catastrophic bearing shell failure is caused by the resultant forces causing stretching of the conrod bolts on a particular cylinder so that the bearing in that con rod becomes elliptical rather than circular, which results in the crankshaft acting as a hammer on the bearing shell because the con rod no longer fits tightly around the crankshaft. In one of the SIBs, BMW changed the con rods and conrod bolts, where the con rod bolts are now single-use, only, which require a specific procedure for stretching when fitting, since those have been fitted the incidence of catastrophic failure seems to be much less.
When this problem first appeared in the earliest E46M3s, BMW blamed the owners! Then it did a few panic band-aid fixes until it properly understood the problem and came up with the revised parts in its later engines. The incidence of bearing shell failure has been considerably reduced, but it will still occur in an engine of this type. Wear of bearing shells, particularly with high mileage and a fair amount of use at high rpm, is normal. The piston speed of the S54 engine is one of the highest seen in a production car, and although I'm no expert on these matters, it seems logical to me to believe that catastrophic bearing shell failure is caused by the resultant forces causing stretching of the conrod bolts on a particular cylinder so that the bearing in that con rod becomes elliptical rather than circular, which results in the crankshaft acting as a hammer on the bearing shell because the con rod no longer fits tightly around the crankshaft. In one of the SIBs, BMW changed the con rods and conrod bolts, where the con rod bolts are now single-use, only, which require a specific procedure for stretching when fitting, since those have been fitted the incidence of catastrophic failure seems to be much less.
1500 quid? Bloody hell..
Quote:
Originally Posted by StickMon "
What's the deal with the saw mark from the timing chain?
Have you replaced the tensioner?"
Just went and picked up the car today, no dramas during the install and had a few extra things done while there.
Had a long chat with the tech who did the bearing install and he started laughing when i asked about the chain marks.. he said its pretty much on all S54's he's pulled apart and is no drama. the chain guides were in perfect nick as was the tensioner. (had the cain guides replaced anyways as i ordered them before hand) I also had the vanos inspected, and was also in top nick.
total labour came to 490 US, extra bits n pieces involved with the bearing swap , like oil,filter, gaskets, coolant and hyrdolic oil (had the steering flushed, aswell as the cooling system) and even added 2 new wipers.
extra bits n pieces came to 330US..
I supplied the bearings and bolts (thanks Ron) , so out of there for around 1100US.
thats much cheaper than a new engine.
Bee, I hear ya mate, just had a bad couple of days man. Appologies Andy, sometimes I am just a dumbass and I know you didnt mean anything by what you said. Ill owe you a beer sometime.
And yeah to be honest, I have no idea how the PO drove the car, all I know is that this car has been bloody good since ive had it.
Quote:
Originally Posted by StickMon "
What's the deal with the saw mark from the timing chain?
Have you replaced the tensioner?"
Just went and picked up the car today, no dramas during the install and had a few extra things done while there.
Had a long chat with the tech who did the bearing install and he started laughing when i asked about the chain marks.. he said its pretty much on all S54's he's pulled apart and is no drama. the chain guides were in perfect nick as was the tensioner. (had the cain guides replaced anyways as i ordered them before hand) I also had the vanos inspected, and was also in top nick.
total labour came to 490 US, extra bits n pieces involved with the bearing swap , like oil,filter, gaskets, coolant and hyrdolic oil (had the steering flushed, aswell as the cooling system) and even added 2 new wipers.
extra bits n pieces came to 330US..
I supplied the bearings and bolts (thanks Ron) , so out of there for around 1100US.
thats much cheaper than a new engine.
Bee, I hear ya mate, just had a bad couple of days man. Appologies Andy, sometimes I am just a dumbass and I know you didnt mean anything by what you said. Ill owe you a beer sometime.
And yeah to be honest, I have no idea how the PO drove the car, all I know is that this car has been bloody good since ive had it.
I can join the list on this one. 107k miles, no warning and then the dreaded knock. Engine lunched. Its not much fun and I would advise all S54 owners to have this as a service item, for the cost of the work it pales into insignificance to the cost and inconvenience of sourcing a second hand or rebuilding your engine.
This was last year now for me. Owned the car since it was 18months old on a 56 plate. Never tracked to my knowledge, regularly serviced, mainly motorway miles. Ended up with a second hand replacement unit from an E46 M3, now with rebuilt vanos, chain tensioner and uprated rod bolts.
Its very stressful to have this happen so would highly recommend getting bearings inspected at max 75k miles. Cars been good as gold since.
Its very stressful to have this happen so would highly recommend getting bearings inspected at max 75k miles. Cars been good as gold since.
frazell said:
see, no pattern to usage but these do need to be factored in for long term owners and people that are considering buying a leggy z4m.
The question i have to ask myself is... how much stress is the supercharger adding to the bearings??? and how i decide when to change my rod bearings.... 30k?? the car already has around 6k supercharged miles and some of them have been prolonged track use miles in hot conditions.
the 2 main concerns for the s54 are vanos and rod bearings. Both can come with ruinous costs.
Beedub, other than stripping it all down and inspecting the bearings regularly, I think the only option is to use oil analysis to help identify degradation of the shell coating?
Regular oil services, twice the interval recommended by BMW is a must too.
Is your oil pump upgraded now you're blown?
Regular oil services, twice the interval recommended by BMW is a must too.
Is your oil pump upgraded now you're blown?