[whyzee125]

If it was n55 I'd say definitely.

Since you're n54 I wouldn't worry about it. N54's are solid motors.

[Ozzie335i]

Originally Posted by Cabdriver

If it aint broke.....

If you've gone fbo + aftermarket turbo you've spent a lot on power upgrades. One spun bearing can mess up the other bearings, along with the turbo innards. Not to mention the residual material left in the oil cooler. Especially when changing the oil pan gasket go a bit further for peace of mind.

[Jeef]

lol..this thread is going to scare a bunch of people

[Barefoot-335is]

From the Bimmerworld page:

“Rod bearings are a typical wear item and more critical on highly stressed engines like a tuned N20 or N54. Although these engines do not rev very high, more mileage with additional boost will eat into bearing life. On our Project 335i we decided to replace the bearings before adding serious power and were surprised to find significant wear at 82,000 miles. Track your bearing wear with regular used oil analysis and plan on rod bearing replacement some time in your engine's future.”

Make your own decision but I plan on keeping my 335is awhile so I will be replacing them with the oil pan gasket

[iqraceworks]

"track your bearing wear with regular uses oil samples".......is the correct answer here.

Blackstone oil analysis can tell you if your bearings need replaced.....and how everything else in the motor is wearing.

[Cabdriver]

Rod bearings are not a maintenance item. You should seek proof for needing to replace but quite honestly, if those need replacement you probably have other issues.

Per iqrace above get an oil analysis. GL!

[TheMidnightNarwhal]

Originally Posted by iqraceworks

"track your bearing wear with regular uses oil samples".......is the correct answer here.

Blackstone oil analysis can tell you if your bearings need replaced.....and how everything else in the motor is wearing.

I honestly am skeptical about that but I still do one every 2 oil changes.

[mweisdorfer]

Idk.

Rod bearings is an e90 M3 issue not an n54 issue.

Maybe if you are going over 600HP, then put some better, after mkt rod bearings on for preventative maintenance so you can sleep better at night.

However, the motor will be out of balance in terms of new parts on the bottom & not at the top. It's almost as if you you should do a valve job up top. IDK if this makes sense. Just thinking out loud.

Idk. You rarely here about rod bearings going bad on an N54. It's about as rare as the head gasket going bad on an N54.

[iqraceworks]

Originally Posted by TheMidnightNarwhal

I honestly am skeptical about that but I still do one every 2 oil changes.

I've been using them for years on multiple different vehicles....they found a head gasket leak on my truck before I did.

They know their stuff.

[TheMidnightNarwhal]

Originally Posted by iqraceworks

I've been using them for years on multiple different vehicles....they found a head gasket leak on my truck before I did.

They know their stuff.

But coolant in oil is easy to detect.

I was watching a video and some guy said his M3 rod bearings wasn't detected by oil anaylisis. I know I think around 2010 ish they changed bearing material and the new one isn't really detectable by oil analysis in the M3.

Hopefully ours is are. But then when you look at some N55s failures of how they just shit the bed out of no where like after a OFHG job it wouldn't help.

[feuer]

Originally Posted by TheMidnightNarwhal

But coolant in oil is easy to detect.

I was watching a video and some guy said his M3 rod bearings wasn't detected by oil anaylisis. I know I think around 2010 ish they changed bearing material and the new one isn't really detectable by oil analysis in the M3.

Hopefully ours is are. But then when you look at some N55s failures of how they just shit the bed out of no where like after a OFHG job it wouldn't help.

Correct. Not easily detectable. I was tracking engine wear on n54 and sent oil for analysis regularly with every oil change. While waiting on the result the bearing(s) spun. I literally got good oil analysis the next day

[TheMidnightNarwhal]

Originally Posted by feuer

Correct. Not easily detectable. I was tracking engine wear on n54 and sent oil for analysis regularly with every oil change. While waiting on the result the bearing(s) spun. I literally got good oil analysis the next day

Damn yeah that sucks. Was it your car or a client's car?

[feuer]

Originally Posted by TheMidnightNarwhal

Damn yeah that sucks. Was it your car or a client's car?

My own, but similar happen to client car, n54 too.

[JuniorB]

Rod bearings were a maintenance item on the m engines, as you know. If your in there, I’d definitely look at them. It’s not often your cracking an oil pan, so if your in there, do them. I done a lot of work on my 60k engine, I pulled mine and found the upper ones were worn more. I ended up replacing them with the King’s bearings, and ARP bolts. I have a picture in my thread on SS under Something for the E60s guys.

[weehe126]

rOd BeArInGs GoOd WhY ChAnGe!?!?

[KnighTT]

I'll take peace of mind any day. I've rebuilt several engines and I always leaned towards replace everything that "could" vs just what you know needs replaced. That isn't in everyone's budget, or ability, but it all depends on how long you want to keep your car and if you want to increase performance.

If you have a higher mileage n54, you plan on keeping it or pushing it with upper tier upgrades, and you have the means to DIY, then just do it. If you have the subframe dropped, I say do all you can to not have to drop it again. Rod bearings are actually pretty easy. As DIY BMW projects go, the parts themselves are even inexpensive.

I just ordered stage 2+ turbos. 335xi. So, my goal is to not need to drop the subframe after this next job unless it is the next overhaul after a few seasons on Road Atlanta.

[Ozzie335i]

Originally Posted by feuer

Correct. Not easily detectable. I was tracking engine wear on n54 and sent oil for analysis regularly with every oil change. While waiting on the result the bearing(s) spun. I literally got good oil analysis the next day

Shhh feuer, this is only supposed to be an issue with N55 and M3 engines. Never mind the N54 engines where the injectors are leaking, thus thining out the oil... The bottom line is that we beat on these engines, proper maintenance or not. As you noted, stuff fails. Why guys don't realize that the bearings are wear items is beyond me. Otherwise why make them removable and replaceable in the first place. The wear is more so when the power output is doubled.

[fatty335]

Originally Posted by feuer

Correct. Not easily detectable. I was tracking engine wear on n54 and sent oil for analysis regularly with every oil change. While waiting on the result the bearing(s) spun. I literally got good oil analysis the next day

FWIW, the "old school" lead and copper rod bearings are much easier to track via oil analysis versus the new tin aluminum bearings. Not sure why. Multiple S65 owners with new formulation bearings reported negligible findings via oil analysis prior to discovering heavily worn bearings during a preventative change.

[Jeef]

rod bearings a wear item?....

[lordbmw]

I had a spun bearing.

No clue why.
Happened a month ago.
I was not the original owner of the car so no clue what he/she did.
May be they drove it like they stole it stone cold.

[feuer]

Originally Posted by Jeef

rod bearings a wear item?....

is a moving part, so yes, wear item, just like a tire

[feuer]

I read that life expectancy on rod bearings on new BMW engines, like b58, that are coated with plastic for smooth stop and go operation are rated for 100k miles. Don't know how accurate that would be, is actually silly, because at 100k miles one engine can have 100k stop/go vs another that could have 50k or 150k stop/go