Definitive E46 M3 Rod Bearing Thread : How Long Has Yours Lasted?

Discussion in 'E46 M3 (2001-2006)' started by M3Chas, Oct 24, 2017.

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What's Happened with Your Rod Bearings?

  1. Still on the factory originals

    143 vote(s)
    52.4%
  2. Still on the recalled originals (Pre-Facelift Only)

    67 vote(s)
    24.5%
  3. Changed them with less than 50k on the engine

    0 vote(s)
    0.0%
  4. Changed between 50-100k

    18 vote(s)
    6.6%
  5. Changed between 100-150K

    26 vote(s)
    9.5%
  6. Changed above 150k

    3 vote(s)
    1.1%
  7. I was too late ; bearings were toast before the sump came off

    7 vote(s)
    2.6%
  8. Changed as a preventative measure but I was too late

    1 vote(s)
    0.4%
  9. Changed but I got lucky

    3 vote(s)
    1.1%
  10. Changed but it was pointless

    5 vote(s)
    1.8%
  1. 28 Mar 2018 at 9:10 PM #141
    M3Chas

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    It's time for me to join. I'll have to see if I can change my position in the poll I set!

    What the the details about mine?

    It's a 2003 M3 SMG with:
    -Shy of 138,000 miles
    -Had the rod bearing recall done.
    -A full service history, with BMW until 90k, a handful of indies and then me from 122k on. I've only put Castrol 10W60 and BMW filters on in my ownership.
    -I've done a few trackdays in it, including a DN at the 'ring.
    -It was daily driven for over a year and it covered 90k within the first 5 years under the same owner.

    And how were mine? Not the worst by quite a way, but I'm glad I changed them :):

    [​IMG]Rod Bearings by Charlieboy, on Flickr

    One bolt however was a pain to remove; mine was on the earlier bolts as well as you can see.
     
  2. 29 Mar 2018 at 6:52 PM #142
    zeta4

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    Changed mine at 110K. Lower shells good upper shells just beginning to show signs of copper.

    My shells were marked CL 113 which I believe indentifies the maker as Mahle-Clevite.
    CL 113 is probably a BMW specific version of their normal CL 112 bearing.

    On their website they say this bearing is of Tri metal design ie steel backing,cast copper lead layer
    for strength and durability, with an electroplated white metal babbit overlay for slipperyness,conformability and embedability.

    They then say that the intermediate copper/lead layer creates an interlocked columnar
    structure capable of withstanding much heavier pulsating loads than any other bearing design.
    However I think most other makes are like this but it explains the design theory.

    Anyway all this to me confirms that the copper/lead layer's function is to support the white metal layer
    and when thats worn through the bearings finished. Just how long the bearing will last after this is unknown
    as copper/lead is still a bearing material but without the white metals specific capabilities.

    This may be obvious but I wondered why the copper/lead layer was there. I was brought up on VP lead/bronze
    bearings (similar to copper/lead) which only had a running in flash and the main bearing was the lead/bronze.

    Im clearly not an expert on bearing design so out of interest if anyone has anything further to add I would appreciate it.
     
    Last edited: Mar 29, 2018
  3. 29 Mar 2018 at 7:44 PM #143
    HARBER07

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    If thats the bolt in the picture, it looks like a torx style head. If so are they not the later M10 bolts?.
     
  4. 17 Apr 2018 at 6:40 AM #144
    Alex5000

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    Confirmation bias! ;) Those look near perfect! If it weren’t for the one showing a smidge copper at the edge, this would definately be in the ‘changed but it was pointless’ category.

    I’ve just quit an Facebook e46 M3 page because of the continual paranoia about bearings. People saying they should be replaced at 50k...:rolleyes:

    I was directing them to this thread, but still no sense. It was mostly American users, they seem to be particularly bad when it comes to forum paranoia.
     
  5. 17 Apr 2018 at 7:51 AM #145
    schooner32

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    I have just changed mine at 78k

    2004
    Documented oil changes every 7k from 20k miles.( Before that was main dealer)
    Late run in service
    I drive it hard and redline it often.

    During the install I concluded that someone had been in there before in the past ( somewhere between new and 30k miles) oil pump had been removed and refitted with damaged bolts. Which makes me curious especially considering all of my bearings showed extremely odd wear down to the copper at the bearing joins where both halves would meet. Seems like they were over torqued or something

    I think they could have lasted about another 30k

    [​IMG]

    [​IMG]

    [​IMG]
    [​IMG]
     
  6. 17 Apr 2018 at 9:24 AM #146
    kimbow

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    Oops, sorry, just voted on this and then realised its E46, not E92. So used to seeing S65 shell worries !:muttley:
     
  7. 17 Apr 2018 at 10:37 AM #147
    Alex5000

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    e46 concerns didn't exist until the e9x issues started arising... :(
     
  8. 17 Apr 2018 at 10:49 AM #148
    TouringRob

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    ? Don't think thats true, S54's didn't start exploding because they were jealous of their younger replacements.
     
  9. 17 Apr 2018 at 11:27 AM #149
    Jimbo25

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    That points more to incorrect bearing sizing, only by a small amount but the excess material has forced the ends on either side to compress slightly and therefore be slightly proud. I don't think you've got regrind sizes in a non-reground crank level of a problem, or it would have announced itself long ago (probably with excessive crankcase ventilation) - I suspect that someone fitted the wrong grade or more likely, didn't measure the clearance.

    I do wonder if a lot of companies advertising drive in/drive out bearing replacements (on the E9x more than the 46) actually spend the time plastigag'ing the bearings to confirm the oil film thickness. BMW are very good with tolerances but there are still 2 different grades for the E46.
     
  10. 17 Apr 2018 at 11:47 AM #150
    schooner32

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    The part number on the old bearing was something like 437/8 or something. I can't quite remember. Was the original bearing I believe. Because it's stamped CL ( clevite ) same stamp as the new bearings but the number is different and I assume it's the bearing from factory that is not available anymore.

    I fitted the standard size bearings ending in 439/440.

    The plastigauge clearance on all my bearings was mainly .050mm but occasionally the bearing showed a tapered result which indicated one side of the bearing being slightly tighter than the other side of the bearing. Still within tolerance.

    Here is the same bearing measured at two locations. Can clearly see the taper.

    On reflection I should have measured the original bearings too

    [​IMG]

    [​IMG]
     
    Last edited: Apr 17, 2018
  11. 18 Apr 2018 at 8:28 AM #151
    M3Chas

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    When I got mine done at Autobahn he told me he'd have the Plastigauge them. After all, if you didn't the engine would be pretty tight to turn over if the clearance was wrong!

    BUT, the conversation gets muddier. Alot of people will change the rod bearing bolts to ARP items, even though the factory bolts have no history of being crap. The ARP bolts are said to ovalise the conrod big end hole. This is even stranger as ARP give the same torque settings for both sets of E46 bolts too and say that to always check for ovality with the conrods. This is also a problem on the E90 too.

    Alex5000, I'd agree.


    I did mine as my M3 is considered high mileage to many and I plan to take it to Spa and maybe other trackdays. That and it's cheaper than £3k for a secondhand engine. The fact that quite a few M3s with significantly lower mileage elsewhere and in this thread were worse than mine however is food for thought.

    As said, they don't need doing, but if you plan on driving the car hard or doing trackdays etc. and you have the spare cash it's not a bad idea to do them. 50k is excessive I've say given the failure rates. That said, there's a spares & repair E46 M3 on eBay now with low mileage (72k) and a shot bottom end.
     
  12. 18 Apr 2018 at 9:53 AM #152
    Chady

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    Apparently only the one std size available now + the over size, I believe the other two sizes were what was used in original manufacture when all was new , from memory it’s just the looser outer spec one now, that way you can’t go wrong,:thumbsup: but still got the option with mains , it’s the front one on them that seems to get the wear,
     
    Last edited: Apr 18, 2018
  13. 18 Apr 2018 at 9:59 PM #153
    Alex5000

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    Not at all, I mean to say that there are a lot more S54 bearing threads since the S65 issues started appearing. Whether the problem existed before or not. It’s been discussed more, and in forum-Land that tends to exaggerate he issue.

    I hope we all agree it’s not in the same league as RACP failure (instances of failure). Although the consequences are comparible depending on severity of failure.

    Very sensible way of looking at it
     
    Last edited: Apr 19, 2018
  14. 19 Apr 2018 at 11:20 AM #154
    TouringRob

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    That I can agree with. My comments were a little tongue in cheek as I knew what you meant. But for me this is a higher priority than RACP failure. Thats easy(ish) to check and keep an eye on.

    If you intend to go on track with your 100K+ M3 I would seriously be looking at replacing big end bearings. These engines are now getting hard to find and will only get harder so expect prices to push above the 2.5k unknown engine price we currently see.

    A quick youtube of "track M3 blown" gets quite a number of hits! I cannot find the video now, think it was linked by member klan8456 showing a rod failure on an SMG which resulted in a pretty nasty crash - engine locked, SMG didn't pull the clutch.
     
  15. 19 Apr 2018 at 11:39 AM #155
    Alex5000

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    Very well put, I would do the same.

    I’ve seen that video you speak of and it is terrifying. At least with a manual you could dip the clutch.
     
  16. 19 Apr 2018 at 12:40 PM #156
    TouringRob

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    Yes, in all honesty I wasn't that worried about bearing issues until I saw that video, I own an SMG and love it however that clip would be my single biggest argument in the never ending manual vs SMG saga.
     
  17. 19 Apr 2018 at 4:51 PM #157
    M3Chas

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    That makes the assumption most people would do that. IME only a handful of people would compute what was happening until it was too late. After all, the same thing happened to Ash Burrows here in a manual car.
     
  18. 19 Apr 2018 at 8:25 PM #158
    Alex5000

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    Probably. But at least you have the possibility to save it.
     
  19. 23 Aug 2018 at 12:09 PM #159
    gooders

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    My 107,000 tracked and daily e46 M3 is having the head gasket fixed as we speak.

    Hughes Brothers BMW Indy didn't entertain the idea of doing the bottom end.

    I would have to assume that this is based on their history of not 'having to' do

    many/any.

    Can l just check??? Is this part of the poll..... "I was too late ; bearings were toast

    before the sump came off" ... owners who's cars actually had bottom end failure??

    Or owners who didn't like the look of their shell bearings once the car was in bits?

    I want to know how many 'real failures' there have been.??
     
    Last edited: Aug 23, 2018
  20. 23 Aug 2018 at 12:18 PM #160
    DaveMSport

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    At 112k, I changed mine recently along with the vanos a be head gasket all as preventative measure.

    There was no major issues or signs of failure. What happened mine for an excuse to rip it open was the vibration damper failed as well as one of the bolts that holds the timing chain tensioner guide in place!!! Had cracked but I spotted it in time before it dropped the chain.

    While at it then, done the lot along with the mains in case the vibration damper coupled with the lightweight flywheel damaged them. All were fine apart from number 7 main starting to wear a little.
     

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