2011 S65 Main Bearings & Rod Bearings

Jobe. · 02-21-2018, 02:51 PM

Obviously there is talk about main bearings. Figured I would share my findings.

2011 M3 78,622 miles at time of removal.

jamba · 02-21-2018, 02:55 PM

interesting. and these rod bearings are original, right?

8500RPM · 02-21-2018, 02:56 PM

The condition of your main bearings makes me sad

Jobe. · 02-21-2018, 02:57 PM

Quote:

Originally Posted by jhoneil

interesting. and these rod bearings are original, right?

Yes original.

admranger · 02-21-2018, 07:24 PM

Quote:

Originally Posted by 8500RPM

The condition of your main bearings makes me sad

Definitely depressing.

pbonsalb · 02-21-2018, 07:44 PM

I am getting more worried about the mains. I may do mine preventatively when I have the energy for a big project.

jmeek83 · 02-21-2018, 07:53 PM

Obviously engine out service... Anyone have any idea on hours of labor to completely tackle this preventatively?

Duk996 · 02-22-2018, 07:08 AM

Those hammer marks on the rearmost are so strange. Mine had them too but my fronts went. Your fronts are ok. Wtf? I saw similar marks on someone else's engine too. How did BMW f up so bad?

Based on the wear I gotta think that at high rpms when the cam chains are pulling the crank up the hardest the bearings are undersized and can't take it. Look how the front top is worn most and then the bottom rears...

These are from my 2011, 46k mile, manual trans.

deansbimmer · 02-22-2018, 08:30 AM

Good post!

The chains do pull the crank upwards and that's why all the front upper main bearings wear out first.

SeattleLSB · 02-22-2018, 08:40 AM

Is this a stock or supercharged car?

doogee · 02-22-2018, 10:18 AM

This is unfortunately a reality that many owners dismiss.

I wont feel confident with my engine until I get the time to do my mains.

SYT_Shadow · 02-22-2018, 10:46 AM

Quote:

Originally Posted by pbonsalb

I am getting more worried about the mains. I may do mine preventatively when I have the energy for a big project.

If you ever want to do this I'm down to help

We can create a main bearing DIY

inTgr8r · 02-22-2018, 11:06 AM

The issue with mains replacement is that there is no 'fix' as there is with rod bearings with more clearance.

With mains change you are just starting the wear cycle over again.
If that's all we're doing then the trick is to determine the mtbf life cycle for them.

E.g. There is no point changing them at 30k if they're known to be good for 80k
Wait for 80 , then you get another 80 after that.

The problem right now is there isn't enough data.

pbonsalb · 02-22-2018, 11:50 AM

Quote:

Originally Posted by SYT_Shadow

If you ever want to do this I'm down to help

We can create a main bearing DIY

I want to do this. I just need to find the time. I am guessing that it would be 2-3 days of work for first timers or 2 long days. It seems straightforward but I don’t know since I have not looked seriously into it. Drop the motor and trans out the bottom, separate the trans, put engine on stand, flip, pull pan and rod bearings, remove bed plate and front cover. Is retiming complicated? Maybe deansbimmer would confirm the basic procedure?

SYT_Shadow · 02-22-2018, 11:57 AM

Quote:

Originally Posted by pbonsalb

I want to do this. I just need to find the time. I am guessing that it would be 2-3 days of work for first timers or 2 long days. It seems straightforward but I don’t know since I have not looked seriously into it. Drop the motor and trans out the bottom, separate the trans, put engine on stand, flip, pull pan and rod bearings, remove bed plate and front cover. Is retiming complicated? Maybe deansbimmer would confirm the basic procedure?

If we're messing with timing we might as well install cams... mine are sitting in the attic... along with the BW LT headers and Xpipe... and subframe bushings... and sway bars...

My brother and I can go up there for a weekend to help if you ever want to, it's just a matter of scheduling it!

rantarM3 · 02-22-2018, 02:46 PM

First:

Then:

It seems the only true fix is a stroker type build with a new custom-ground crank.

Jobe. · 02-22-2018, 04:39 PM

Quote:

Originally Posted by deansbimmer

Good post!

The chains do pull the crank upwards and that's why all the front upper main bearings wear out first.

Very good point!

Quote:

Originally Posted by SeattleLSB

Is this a stock or supercharged car?

Only mod was exhaust.

Shaan · 02-23-2018, 09:49 AM

Quote:

Originally Posted by Jobe.

Very good point!

Only mod was exhaust.

did you get the work done locally ? i see youre in huntsville

Jobe. · 02-23-2018, 02:14 PM

Quote:

Originally Posted by Shaan

did you get the work done locally ? i see youre in huntsville

I'm actually located in Huntsville, Alabama. Not Huntsville TX, although I used to live in Texas.

I didn't do the bearings out of preventative maintenance. I tore the engine down because cylinder 4 had low compression.

BKrunner · 02-23-2018, 04:48 PM

http://www.m3post.com/forums/showpos...81&postcount=1

Perhaps what was said in the above post is the case?

aus · 02-23-2018, 04:50 PM

I guess the next question is, would changing out the rod bearings help the mains in any way?
.

8500RPM · 02-23-2018, 06:45 PM

Quote:

Originally Posted by aus

I guess the next question is, would changing out the rod bearings help the mains in any way?
.

Not one bit. 1 has nothing to do with the other.

02-21-2018, 02:51 PM	#1
Jobe. Second Lieutenant 120 Rep 252 Posts Drives: BMW M3 Join Date: Oct 2015 Location: Huntsville iTrader: (7)	2011 S65 Main Bearings & Rod Bearings Obviously there is talk about main bearings. Figured I would share my findings. 2011 M3 78,622 miles at time of removal. Attached Images
	Appreciate 7 msan434.00 admranger4232.00 Duk996250.50 inTgr8r2513.50 aus1029.00 8k_v845.50 DrFerry10035.50 Tweet Quote

02-21-2018, 02:55 PM	#2
jamba Captain 171 Rep 762 Posts Drives: M3 E90 Jetblack Join Date: Oct 2013 Location: WA iTrader: (4) Garage List 2009 BMW E90 M3 [0.00]	interesting. and these rod bearings are original, right?
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02-21-2018, 02:56 PM	#3
8500RPM First Lieutenant 158 Rep 302 Posts Drives: 2012 M3 CP Join Date: Dec 2017 Location: Ft. Lauderdale, FL iTrader: (0)	The condition of your main bearings makes me sad
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02-21-2018, 07:44 PM	#6
pbonsalb Lieutenant General 7679 Rep 13,761 Posts Drives: 18 F90 M5, 99 E36 M3 Turbo Join Date: Feb 2011 Location: New England iTrader: (4)	I am getting more worried about the mains. I may do mine preventatively when I have the energy for a big project.
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02-21-2018, 07:53 PM	#7
jmeek83 Private 37 Rep 50 Posts Drives: 13 M3 Coupe Join Date: Feb 2014 Location: Chicago iTrader: (0)	Obviously engine out service... Anyone have any idea on hours of labor to completely tackle this preventatively?
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02-22-2018, 07:08 AM	#8
Duk996 Second Lieutenant 251 Rep 256 Posts Drives: E92 m3 Join Date: Oct 2017 Location: west virginia iTrader: (0)	Those hammer marks on the rearmost are so strange. Mine had them too but my fronts went. Your fronts are ok. Wtf? I saw similar marks on someone else's engine too. How did BMW f up so bad? Based on the wear I gotta think that at high rpms when the cam chains are pulling the crank up the hardest the bearings are undersized and can't take it. Look how the front top is worn most and then the bottom rears... These are from my 2011, 46k mile, manual trans. Attached Images
	Appreciate 0 Quote

02-22-2018, 08:30 AM	#9
deansbimmer BimmerPost Supporting Vendor 4324 Rep 3,023 Posts Drives: 2011 E93 M3 Join Date: Nov 2014 Location: DFW, Texas iTrader: (17) Garage List 1988 E30 M3 [0.00] 2006 E46 M3 [0.00] 2024 X7 M60i [0.00] 2011 BMW M3 [0.00]	Good post! The chains do pull the crank upwards and that's why all the front upper main bearings wear out first.
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02-22-2018, 08:40 AM	#10
SeattleLSB First Lieutenant 80 Rep 366 Posts Drives: 2022 X5, M50I Join Date: Jan 2006 Location: Seattle, Washington iTrader: (6)	Is this a stock or supercharged car?
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02-22-2018, 10:18 AM	#11
doogee Major 770 Rep 1,263 Posts Drives: '08 M3, '09 328xi Sport Wagon Join Date: Oct 2008 Location: Ancaster, ON, Canada iTrader: (0)	This is unfortunately a reality that many owners dismiss. I wont feel confident with my engine until I get the time to do my mains. __________________
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02-22-2018, 11:06 AM	#13
inTgr8r Lieutenant General 2514 Rep 11,671 Posts Drives: M2 Comp Join Date: Mar 2006 Location: Toronto iTrader: (10)	The issue with mains replacement is that there is no 'fix' as there is with rod bearings with more clearance. With mains change you are just starting the wear cycle over again. If that's all we're doing then the trick is to determine the mtbf life cycle for them. E.g. There is no point changing them at 30k if they're known to be good for 80k Wait for 80 , then you get another 80 after that. The problem right now is there isn't enough data. __________________ nada
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02-22-2018, 02:46 PM	#16
rantarM3 Captain 247 Rep 756 Posts Drives: E90 M3 Join Date: Aug 2011 Location: Florida iTrader: (3)	First: Then: It seems the only true fix is a stroker type build with a new custom-ground crank.
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02-23-2018, 04:48 PM	#20
BKrunner New Member 0 Rep 15 Posts Drives: 2011 AW, E92 M3, 10K miles Join Date: Nov 2014 Location: Calgary, Canada iTrader: (1)	http://www.m3post.com/forums/showpos...81&postcount=1 Perhaps what was said in the above post is the case?
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02-23-2018, 04:50 PM	#21
aus Major General 1029 Rep 9,093 Posts Drives: Odysse Join Date: Jul 2005 Location: Seal Beach, CA iTrader: (10)	I guess the next question is, would changing out the rod bearings help the mains in any way? . __________________ Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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