I'm going to preventatively replace my 72K N55 rod bearings

9krpmrx8 · 01-21-2019, 10:10 AM

I mean, that is not ideal for sure, but I doubt these would have been a real problem for a long while.

But man, thanks for sharing your work, I appreciate it. I am curious about your driving habits and OIC's as well.

fatty335 · 01-21-2019, 11:39 AM

Quote:

Originally Posted by weehe126

Where is this car located? Wonder if it's cold start in cold weather related.

Car was a Texas car its whole life, now in Oklahoma so I seriously doubt cold weather was an issue here.

feuer · 01-21-2019, 12:22 PM

Quote:

Originally Posted by 9krpmrx8

I mean, that is not ideal for sure, but I doubt these would have been a real problem for a long while.

But man, thanks for sharing your work, I appreciate it. I am curious about your driving habits and OIC's as well.

You are being ridiculous now. They won't be a problem for a long time as long as car isn't driven lol . Everyone with a little knowledge will disagree with you. As someone who has rebuild dozen of these engines and is dumb to attach mileage or time time frame I will tell you probably 12k or 1y max left on those bearings.

9krpmrx8 · 01-21-2019, 01:52 PM

Quote:

Originally Posted by feuer

You are being ridiculous now. They won't be a problem for a long time as long as car isn't driven lol . Everyone with a little knowledge will disagree with you. As someone who has rebuild dozen of these engines and is dumb to attach mileage or time time frame I will tell you probably 12k or 1y max left on those bearings.

I could give two shits what your opinion is. And now you have rebuilt dozens of N55's? GTFOH.

feuer · 01-21-2019, 02:36 PM

Quote:

Originally Posted by 9krpmrx8

I could give two shits what your opinion is. And now you have rebuilt dozens of N55's? GTFOH.

wow! What a surprise here. Shit can only give shit

feuer · 01-21-2019, 03:23 PM

fatty335 sorry to pollute your thread. I wish there was less keyboard warriors. Anyhow, I'm doing one now with 100k. 2nd owner for the last 70k. Take a look.

fatty335 · 01-21-2019, 04:48 PM

Quote:

Originally Posted by feuer

fatty335 sorry to pollute your thread. I wish there was less keyboard warriors. Anyhow, I'm doing one now with 100k. 2nd owner for the last 70k. Take a look.

Ouch, those are certainly worse than mine. Are you changing due to a problem or just as a "preventative measure" like me? N54 or N55?

feuer · 01-21-2019, 05:57 PM

Quote:

Originally Posted by fatty335

Ouch, those are certainly worse than mine. Are you changing due to a problem or just as a "preventative measure" like me? N54 or N55?

Due to a problem. No noise. Good oil report. However, silent code for oil pressure (Castrol 0w-40) when Engine gets hot which is often caused by worn out bearings.

Pladi · 01-21-2019, 06:05 PM

Quote:

Originally Posted by feuer

Due to a problem. No noise. Good oil report. However, silent code for oil pressure (Castrol 0w-40) when Engine gets hot which is often caused by worn out bearings.

Hey feuer thank you for your input. Do you think that engine was neglected ? In terms of oil intervals or anything like that ?

Kev0 · 01-21-2019, 06:08 PM

Quote:

Originally Posted by feuer

Due to a problem. No noise. Good oil report. However, silent code for oil pressure (Castrol 0w-40) when Engine gets hot which is often caused by worn out bearings.

What was the code and how did you diagnose it or came to find out it was the bearings? Interested to know.

feuer · 01-21-2019, 06:08 PM

Quote:

Originally Posted by Pladi

Hey feuer thank you for your input. Do you think that engine was neglected ? In terms of oil intervals or anything like that ?

No, it wasn't, I will post photos from the oil pan and oil pick tomorrow from work. Very clean. I also did the VCG recently and the head was pristine.

TheMidnightNarwhal · 01-21-2019, 06:14 PM

Damn ok. Hope N54s are better.

feuer · 01-21-2019, 07:14 PM

Quote:

Originally Posted by Kev0

What was the code and how did you diagnose it or came to find out it was the bearings? Interested to know.

2F7B. Didn't cause CEL nor showed on CIC. Only when you scan DME. Engine is put together now and isn't getting that code so the worn bearings were causing drop in oil pressure.

rich_mane · 01-21-2019, 07:57 PM

I'm happy this thread exists. This is all excellent information and definitely has convinced me to go ahead and plan to do this soon. I bought it at 50k, at 108k now and plan on keeping the car for much more than that. I've kept up with maintenance quite well and also use Castrol 0w40. No problems yet but I don't want to wait until it develops.

Pladi · 01-21-2019, 09:04 PM

Quote:

Originally Posted by Kev0

What was the code and how did you diagnose it or came to find out it was the bearings? Interested to know.

U can monitor this with MHD. Typical oil pressure numbers are easy to fnd through different logs under load or idle. Usualy 40 PSI idle at operating temp and 80 PSI Full throttle. DME will log guessing shadow codes if the pressure is low due to less restriction when there is less clearance.

Pladi · 01-21-2019, 09:06 PM

Quote:

Originally Posted by feuer

2F7B. Didn't cause CEL nor showed on CIC. Only when you scan DME. Engine is put together now and isn't getting that code so the worn bearings were causing drop in oil pressure.

It would be amazing if this engine was logged and u can share those logs but thats probably highly unlikely.

weehe126 · 01-21-2019, 09:47 PM

This is all very interesting and makes me want to consider a built engine sooner rather than later.

My main question is what causes bearing wear like this? I know on the S65 wear on ALL bearing is normal and they are proactively replaced. What could cause more bearing wear on only 1-2 cylinders? I know the stock tune pretty much runs on the knock sensors and pulls timing a lot. Would this knock cause this type damage over time or is this an oil issue due to too tight of clearance?

fatty335 · 01-21-2019, 10:01 PM

Quote:

Originally Posted by weehe126

This is all very interesting and makes me want to consider a built engine sooner rather than later.

My main question is what causes bearing wear like this? I know on the S65 wear on ALL bearing is normal and they are proactively replaced. What could cause more bearing wear on only 1-2 cylinders? I know the stock tune pretty much runs on the knock sensors and pulls timing a lot. Would this knock cause this type damage over time or is this an oil issue due to too tight of clearance?

So that is the million dollar question, isn't it. Based on my research and opinion, I suspect it is a combination of many factors, to include:
Design (tight tolerances, bearing composition, etc.)
Factory recommended OCIs that almost all followed due to lease/free maintenance
Driving style (i.e. driving hard on cold oil)
Improper or delayed maintenance
Poor quality fuel
Tuning

Obviously these are weighted differently in each instance but I suspect they all come into play in some measure. I doubt anyone will ever be able to narrow it down to one thing.

weehe126 · 01-21-2019, 10:13 PM

Quote:

Originally Posted by fatty335

So that is the million dollar question, isn't it. Based on my research and opinion, I suspect it is a combination of many factors, to include:
Design (tight tolerances, bearing composition, etc.)
Factory recommended OCIs that almost all followed due to lease/free maintenance
Driving style (i.e. driving hard on cold oil)
Improper or delayed maintenance
Poor quality fuel
Tuning

Obviously these are weighted differently in each instance but I suspect they all come into play in some measure. I doubt anyone will ever be able to narrow it down to one thing.

Yeah would make sense to be a combo otherwise there would be a lot more failed engines before 100k miles. What fuel do you use, 91 or 93?

fatty335 · 01-21-2019, 10:18 PM

Quote:

Originally Posted by weehe126

Yeah would make sense to be a combo otherwise there would be a lot more failed engines before 100k miles. What fuel do you use, 91 or 93?

VP 94 octane on the OTS MHD 1+ for 91 octane and I still see some corrections

bbnks2 · 01-22-2019, 08:20 AM

Quote:

Originally Posted by TheMidnightNarwhal

Damn ok. Hope N54s are better.

N54s use the same bearings and see the same oiling issues.

TheMidnightNarwhal · 01-22-2019, 08:24 AM

Quote:

Originally Posted by bbnks2

N54s use the same bearings and see the same oiling issues.

Yeah but I rarely see threads or feuer I don't think he has done manny and mostly just N55s?

01-21-2019, 10:10 AM	#89
9krpmrx8 Clean is the new cool, keep it that way. 814 Rep 1,685 Posts Drives: 11' Alpine White 335i Sedan Join Date: Jan 2016 Location: San Antonio, Texas iTrader: (0)	I mean, that is not ideal for sure, but I doubt these would have been a real problem for a long while. But man, thanks for sharing your work, I appreciate it. I am curious about your driving habits and OIC's as well. __________________ 2011 335i, FBO, N55+ Turbo, full E85, S55 intercooler, etc. 2015 X5 35i Xdrive
	Appreciate 0 Quote

01-21-2019, 03:23 PM	#94
feuer Major General 4288 Rep 9,224 Posts Drives: wife crazy! Join Date: Apr 2015 Location: Chicago, IL iTrader: (5)	fatty335 sorry to pollute your thread. I wish there was less keyboard warriors. Anyhow, I'm doing one now with 100k. 2nd owner for the last 70k. Take a look. Attached Images
	Appreciate 2 Pladi721.50 99937.50 Quote

01-21-2019, 06:14 PM	#100
TheMidnightNarwhal Major General 2815 Rep 6,384 Posts Drives: 11' 335is DCT Join Date: Jun 2015 Location: Gatineau, Quebec iTrader: (0)	Damn ok. Hope N54s are better.
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01-21-2019, 07:57 PM	#102
rich_mane First Lieutenant 143 Rep 227 Posts Drives: 2011 E92 335i Join Date: Jan 2016 Location: S.FL iTrader: (1)	I'm happy this thread exists. This is all excellent information and definitely has convinced me to go ahead and plan to do this soon. I bought it at 50k, at 108k now and plan on keeping the car for much more than that. I've kept up with maintenance quite well and also use Castrol 0w40. No problems yet but I don't want to wait until it develops.
	Appreciate 0 Quote

01-21-2019, 09:47 PM	#105
weehe126 Brigadier General 1189 Rep 3,228 Posts Drives: 2017 340i Join Date: Apr 2014 Location: San Antonio iTrader: (2)	This is all very interesting and makes me want to consider a built engine sooner rather than later. My main question is what causes bearing wear like this? I know on the S65 wear on ALL bearing is normal and they are proactively replaced. What could cause more bearing wear on only 1-2 cylinders? I know the stock tune pretty much runs on the knock sensors and pulls timing a lot. Would this knock cause this type damage over time or is this an oil issue due to too tight of clearance?
	Appreciate 0 Quote