10-07-2020, 08:50 AM | #1 |
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Rod Bearings?
My 2018 M4 is coming up on the end of warranty before the next oil change. With that I plan on going ahead and having the crank hub fix done by my local shop. Went to get a quote and schedule and they recommended replacing the rod bearings while we’ve got it in there too. I plan to convert it to flex fuel with the Ecutek tune and the kit from Bend Calibration. I hadn’t heard of many issues with rod bearings on the S55 other than the handful my mechanic has on their Instagram.
What is everyone’s thoughts on preventative rod bearing replacement on the S55? |
10-07-2020, 09:15 AM | #2 |
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Friggin whaaaaat...??? No.
Let's just schedule a heart transplant while we do your colonoscopy...you know, while we're in there...
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10-07-2020, 09:19 AM | #3 |
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10-07-2020, 09:25 AM | #4 |
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depending on who is doing your crank hub they are already removing the oil pan, so rod bearings are not such a stretch from there
However, there is little to no documentation of the rod bearings of the S55 having an issue. Don't replace what isn't broken or not likely to fail. Just the fact that they recommended this makes me question this shop entirely. |
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10-07-2020, 09:25 AM | #5 |
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Better to use a specialty shop, or one that isn't looking to do extra work.
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10-07-2020, 01:38 PM | #6 |
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Just throwing this out there. Not too many ppl inspecting them...
https://f80.bimmerpost.com/forums/sh...6&postcount=19 |
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FriedPiston1976.50 |
10-12-2020, 05:32 PM | #7 |
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I would recommend getting the rod bearings replaced if you're planning to keep the car for a few years.
This example was at 47k miles, with frequent oil changes starting at 30k miles: Some have even seen premature wear at only 16k miles. |
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10-12-2020, 07:29 PM | #8 | |
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Do you know what would cause rod bearing wear like that? |
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M_Torx337.00 |
10-12-2020, 07:31 PM | #9 |
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^ really?
Rod bearings on this platform have not been on the forum radar... given how the forum is a small percentage of actual F8X owners, the issue of rod bearings are probably not even a issue. Let’s not tempt the rod bearing gods to start up on this platform lol. |
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10-13-2020, 02:21 AM | #10 |
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Premature rod bearing wear is almost often a lubrication/maintenance issue. Likely folks who go on occasional spirited driving sessions, while religiously sticking to the 10k OCI using low grade 5w30 oil.
Not all topics are discussed on the forums nowadays, but there are literally 3 examples given in this thread. The 3rd one was through verbal confirmation from a reputable BMW tuning shop, who happened to replace theirs at 16k miles. This is not to say the S55 suffers the same rod bearing failure as the S65, but it's definitely happening. There's also no way to fully determine the present condition without having to R&R the existing rod bearings. UOA is more for entertainment purposes, IMO. I've sent an oil sample from a spun rod S55, and the UOA report didn't show any concrete indicators, only an unusual increased in calcium. |
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10-14-2020, 06:22 AM | #11 |
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Hey Guys,
I think the rod bearings will be a problem as with the N54 and N55. In my workshop alone, 6 N54 engines died from spun rod bearing! All of them had mileage of over 100,000 km, I don't know how many miles that is. About 63K? Here is a picture of the rod bearings that were changed prematurely! Oil was always driven 5W40 or 5W50 and changed every 10tkm! As soon as my M4 has 50,000KM down I will remove and inspect the rod bearings. Sorry for my bad english. Greetings from Germany :-) |
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10-14-2020, 07:34 AM | #12 |
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I still say "if it ain't broke, don't fix it"! Never had any rod bearing problems with previous N54 and N55 cars, have a few friends with N54 cars and 60K miles, zero issues. Depends a lot on how hard you drive the car and how often. That said, the rod bearings in early S54 engines in E46 M3s were problematic, but the S54 had a very high redline and there were numerous failures until BMW changed the bearing specification in later model years.
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10-14-2020, 12:27 PM | #14 | |
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Anyone considering getting this preventative service done should also look into getting WPC treatment for the replacement rod bearings. One popular vendor that does this is www.wpctreatment.com. IIRC, cost for the treatment was around $65 for all 12 halves. ACL sells a set of rod bearings (6B1584HX) with slightly higher clearance (+0.001") than factory. This should help offset any minor dimensional change on the rod bearings as a result of the metal surface treatment. |
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behindthen0thing839.50 |
10-15-2020, 12:25 PM | #15 | |
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You can see that rod bearings was not tragic but in few k kilometers should be replaced. Keep in mind that i dont smoke tires in every corner, so it depends how you ride and how often you replace oil. I change oil every 5-6 K kilometrs and use Millers CFS 5w40 nt+. |
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10-15-2020, 04:23 PM | #16 |
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The S55 was originally designed for LL01 which calls for roughly 3.5 HTHS- those of you that are using 5w50, you guys aren't worried that it's too thick increasing bearing wear during cold starts?
I'd run an LL01 0w30/ 5w30 / 0w40 / 5w40 but certainly wouldn't touch a 5w50 (No LL01 / A40 / 229.5 etc), just my personal choice though. |
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10-16-2020, 07:44 AM | #18 |
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If this is indeed a common issue on the S55 just coming into light and not just a few one offs, then there wouldn't be any symptoms until you're spun and by then it's too late.
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nbennettksu1397.00 |
10-16-2020, 04:12 PM | #19 |
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Anyone knows what the bearing clearances should be according to BMW?
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10-17-2020, 05:08 AM | #22 | |
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