[fatty335]

Originally Posted by fastboatster

I’m also looking to do the rod bearings on the new to me e90 335i (build date 06/2011) with 109 kmiles. I see that king bearings are backordered everywhere. I don’t really want to use expensive OEMs especially that I don’t yet know which sizes I need to order. Really considering Kolbenschmidt bearings but concerned they might only be good as a replacement for “yellow/red” shell combo. looking to see what other (preferably not to expensive) options are available. Has anyone used ACL race bearings? VAC is also making rod bearings but these are around 500 a set, and I don’t think I need these since I’m not building this engine.

Fastboatster, while I chose to go OE to reduce the chances of introducing any additional clearance issues, many others have used K-schmidt, King, VAC, etc. bearings with good results. I wouldn't hesitate to spec a set of quality bearings from a known aftermarket supplier; if you do use aftermarket, I recommend measuring each journal before final assembly. Good luck and let us know how it goes.

[fastboatster]

Originally Posted by fatty335

Fastboatster, while I chose to go OE to reduce the chances of introducing any additional clearance issues, many others have used K-schmidt, King, VAC, etc. bearings with good results. I wouldn't hesitate to spec a set of quality bearings from a known aftermarket supplier; if you do use aftermarket, I recommend measuring each journal before final assembly. Good luck and let us know how it goes.

Purchased a set of ACL bearings, these turned out to be almost the same price as Kolbenschmidt, they were just twice as expensive on the FCP Euro website. Will post once I get all the rod and oil pan bolts and start tearing things down. I figure doing the rod bearings at 110kmiles when fixing an oil pan leak is not a bad idea, especially given that there was a P250F code (engine oil level too low) logged in DME some miles ago. Hopefully I won’t discover that rod bearings are so bad I will want to get the engine out and inspect the main bearings and other rotating pieces like cams etc

[335togo]

Originally Posted by hassmaschine

Ya'll are crazy in this forum. There's basically zero reason to be concerned about N55 rod bearings.. but here we are. :|

I'm with you....Save you pesos buddy one day you're going need them something actually necessary like paying your mortgage or retiring.

[fastboatster]

Originally Posted by fatty335

Fastboatster, while I chose to go OE to reduce the chances of introducing any additional clearance issues, many others have used K-schmidt, King, VAC, etc. bearings with good results. I wouldn't hesitate to spec a set of quality bearings from a known aftermarket supplier; if you do use aftermarket, I recommend measuring each journal before final assembly. Good luck and let us know how it goes.

I was only able to do one set of bearings today (rod #6) as the temps dipped and I was underdressed to work on my car outside and was uncomfortable af. When I dropped the oil pan 2 days ago, I only took a look at the lower shell on #6. The upper does look a lot worse. I think it was a good idea to inspect the rod bearings while doing the oil pan gasket. I’m going to say I’m already having a little bit of a buyers remorse and “disillusionment” with the n55 platform. It’s a lateral move from my (almost sorted out) b8 s4, and it doesn’t make as much power as easily as the n54 which can still end up costing less even after addressing its issues. </end rant>. Pics:

[wheela]

Fastboatster, I'm not familiar with how good bearings should look, what are your thoughts on the condition of that cylinder 6 bearing you took out? Do they look bad for 110k miles?

[fastboatster]

Originally Posted by wheela

Fastboatster, I'm not familiar with how good bearings should look, what are your thoughts on the condition of that cylinder 6 bearing you took out? Do they look bad for 110k miles?

I am no expert and perhaps somebody else will have a different opinion and will chime in, but rod bearings normally should not have almost any wear. I tore down my blown 3.0t from my b8 s4 which had 150kmiles almost 2 years ago, and the rod bearings looked brand new. Many rod bearings from parted out engines (not n55s, obviously) on eBay look a lot better than my bearings on cylinder #6. Not sure if these are the worst or the best yet. I might not get to do the rest of them until the next week after it stops to rain and I also get some warm mechanic coveralls and good thermal layers.

[fastboatster]

Pics of how the rest of the bearings is looking. I had replaced all of them but still need to put the oil pump back on. I couldn’t do it yesterday since it started to rain right when I got to the cylinder #1 - I was going from #6 forward to the front of the engine saving number 1 for last. I probably didn’t need to, I was able to break the oil pump sprocket bolt loose without any struggle using 1/2” t45, breaker bar and adjustable pin spanner wrench to hold the sprocket.
Will resume when weather permits. Bearing clearances are all between 0.0015 and 0.002”, somewhere around 0.0018 would be my guess.

[fatty335]

Originally Posted by fastboatster

Pics of how the rest of the bearings is looking. I had replaced all of them but still need to put the oil pump back on. I couldn’t do it yesterday since it started to rain right when I got to the cylinder #1 - I was going from #6 forward to the front of the engine saving number 1 for last. I probably didn’t need to, I was able to break the oil pump sprocket bolt loose without any struggle using 1/2” t45, breaker bar and adjustable pin spanner wrench to hold the sprocket.
Will resume when weather permits. Bearing clearances are all between 0.0015 and 0.002”, somewhere around 0.0018 would be my guess.

Fastboat,

Those are not the worst factory bearings I've seen come out of an N55, but yours do exhibit wear. What yours and every other worn N55 rod bearing says to me is that under some condition or combination of conditions, the bearing face is coming into contact with the crank. With appropriate clearance, oil pressure, and quality parts, this should not happen. I hope you enjoy many more years of use out of your recently refreshed engine. Thanks for sharing and please remember to prime the engine before firing for the first time.

[Ozzie335i]

All good fastboat. If nothing else, you know where you stand, and can move on. In my case I spent a ton of money, and was relieved that my rod bearings had not started to disintegrate and potentially kill all the effort and money that I spent before that time.

[fastboatster]

Sorry for not getting you updated frequently. I was able to start the engine for a first time today with new rod bearings. It’s been really challenging with rains almost every other day or few days in a row. I primed the oiling system 3 times for 10 seconds as prescribed, though I had to wait for 5 mins between the each 10 sec crank as the battery was very discharged and my charger would need to have 5 min breaks between each “engine start” attempts. But I think it should be good. The bottom end sounds healthy although I got what sounds like a bad pcv whine up top. I think that when I was trying to pull the ignition coil cover in the back of the engine from under the upper strut brace bar, I didn’t realize that the bar needs to come off, and I was just forcing that cover between the bar and the valve cover too much. Perhaps the valve cover formed some cracks after this “disrespectful” behavior. Will try to attach a video to this post.
Other random pieces of info - all my lower shells had a piece of pn stamped on them which ended in 718, which was probably 11247576718 which got superseded after 08/02/2011 by 11247628035 which is a blue bearing shell.
All the uppers had pns ending in 715 (violet), which is still current revision. I was also able to see some numbers on the connecting rods such as 7586492 which I think corresponds to 11247586492, which is an older connecting rod revision.

P.S. I think I need to start some kind of a "build" thread for this car because I have already done and will have to do many things to it. I also tore down the mechatronik and replaced the separator plate and shift solenoid; my FRM module also died when I disconnected the battery and I will either have to repair it and document it or grab one from the junkyard. I might or might not have to do the valve cover replacement (perhaps that sound in that video is actually turbo noise). Also, the idle keeps going up about 100 rpm every few mins, continues like this for a few seconds and then settled back down - perhaps an effect of bad FRM?

[EnzoKhan]

Hello everyone,

I just had my rod bearings replaced by a good independent shop (Dixon Motorsports, Wixom MI) preventativly with ACL STD bearings. My oil pan gasket needed replacement so figured might as well have the rod bearings done. I also noticed tiny metal bits in the drained engine oil- that was the final draw. During the service they also replaced a weeping radiator and oil filter housing gaskets. I bought the car at 118k miles. It now has about 120k miles and noticed over 20k miles OCI during its early life. The previous owner was also running mhd 2+ tune with FBO. Since the replacement, I have only driven like 20 miles and it felt great!

2011 335xi E92 M-Sport
RB mileage: 120,883mi

Let me know your thoughts on the condition of the bearings.

Attached are some images of the oem bearings:

[fastboatster]

Originally Posted by RbAk

Hello fastboatster, can you please let us know if you have re encountered any problem after replacing your rod boaring?

Lots of problems, lol) intake, boost leak and 2 bad solenoids - boost control and exhaust flap solenoids. Already got about 2k street miles on this set of bearings, no track or autox miles so far.

[Will_460cs]

Hi,

I did mine on my OCTOBER 2010 E90 N55 at 69K miles with full BMW SH.- I'm in the Uk.

Bearing 3 was the worst, with the upper being the worst by far and separately photo'ed.

I used new BMW bolts / bearings, every bearing clearance was checked - All were approx .038mm according to plastigauge (thats abit under 2 thou for you imperialists)

I did this as overly large set of maintenance following loosing reverse gear synchro.

It justified my purchase of a2 post lift and a 2nd hand Snapon tech angle.

The oil pump bolt was pain - I made a special tool similar to the one shown in ISTA one to hold it whilst I torqued it.. rightly or wrongly I also used some thread locker on this bolt.

The only other thing that scared (confused) me was the clearance between the Oil sprocket and the lower guide, it's really close where the metal bends over the sprocket.

I had to replace the plastic timing gear as I found one plastic tab in the oil pan (about a 5mmx5MMx1mm thick - so small), this came from upper timing gear off the long rail - it was a tab that hold the piece of plastic to other piece of plastic adjacent to the crank hub.

Im pretty sure if I had paid someone to do this that would have been ignored except by perhaps the most fastidious places.

At the same time I did the Oil filter housing and cooler gaskets, removed the carbon from the inlet valves, and a multitude of gaskets, a vanos solenoid service, spark plugs and anything else it needed.

This was after I had got the gearbox off and had the reverse gear synchro replaced.

From the colour of the engine BMW service intervals are way too long.

I've owned the car since December 2017 and 50k miles.

It took be an overly long time..

I’m now moving rightly or wrongly from Fuchs oil to millers motorsport cfs (both were 5w40), and dispensing with lll04/01 certification and changing oil at 1 year/5k intervals.

[Will_460cs]

Originally Posted by fastboatster

I was only able to do one set of bearings today (rod #6) as the temps dipped and I was underdressed to work on my car outside and was uncomfortable af. When I dropped the oil pan 2 days ago, I only took a look at the lower shell on #6. The upper does look a lot worse. I think it was a good idea to inspect the rod bearings while doing the oil pan gasket. I’m going to say I’m already having a little bit of a buyers remorse and “disillusionment” with the n55 platform. It’s a lateral move from my (almost sorted out) b8 s4, and it doesn’t make as much power as easily as the n54 which can still end up costing less even after addressing its issues. </end rant>. Pics:

Your number 2 looks similar to my Number 3 Upper. it almost looks like the bearing is starting to sheer its surface in small chunks revealing the next layer - I wonder why this happens like this as I expected it to be like the abrasion marks as per the other cylinders.

[Malteser_wfj]

My 119k mile engine was knocking and had loads of metal in the oil, so when I get it to an engine builder/mechanic I can trust enough I'll post pictures of what my bearings look like.

I think they'll be quite bad as for an unknown length of time the oil filter carrier was missing the basket with the bottom o-ring.... It also had oil change intervals of over 10k for most of it's life from 2012. (Manual and March build date)

What would your recommendations be - try and get my engine rebuilt or swap in a pre-reconditioned unit like this? https://www.ebay.co.uk/itm/165353818246

[wheela]

What are your guys' thoughts on main bearings? Do these ever go out? Are you replacing those too when you do your rod bearings, or are they not a problem and you just let those be?

[CalvinNismo]

It’s quite involved to change the main bearings, you’d have to split the block to remove the crank, so it’s an engine out job.

I’ve not read about main bearings having any issues personally, though I’d be interested to know if anyone has had issues.

[yupetc]

When I had my rod bearings spun and two of six basically welded into the journal, I took the whole motor apart and yet still found just normal wear on the main bearings. That car was at 189k miles when I did that, so that says a lot about how well situated the main bearings are. I replaced the main bearings with aftermarket set just because at the time of redoing the motor, I might as well. But I can attest the main bearing being fully capable to last. The real moving part taking the stress during oil starvation are the rod bearings.

[Malteser_wfj]

Originally Posted by wheela

What are your guys' thoughts on main bearings? Do these ever go out? Are you replacing those too when you do your rod bearings, or are they not a problem and you just let those be?

My main bearings at 120k on a car that had extended oil changes (as high as 17k one time) that had spun no1 rod bearing.


*NB: the bearings aren't in any order by the way!! I got them back in a box and put them next to each other myself

[Will_460cs]

Any thoughts on the bearings I posted above?

- The dark hue - I assume is heating?
- The spotting on one cylinder - Misfire/knock event?
- Some contamination scratches.


- BTW for reference an oil anyways was done prior to this (at last oil change around 66K) and was green. 14 PPM Alu.

I am putting less faith in oil testing after seeing these bearings.

[scotthilly]

I uploaded a data point in a seperate thread of my N55 335i with 94k miles, 5-8k lifetime oil changes, running MPPK but otherwise stock.

They were fine but I'm glad I did them. Not great or good, just fine. I don't think they would've gone out in the near future so this isn't something to rush to, but easy to do while the OPG is done.