Break-in Procedure

[Jimbo's M]

For those that go back long enough back to remember this site...

http://www.madrussian.net/m3/faq.shtml#28

Did BMW recall E46 M3's for engine failure related issues?

Technically no: BMW issues a "service action." To quote BMWNA, "The problem has been identified as contamination of the engine lubricating system during assembly in combination with unfavorable tolerances in the engine oil pump for the M3 coupe/convertible produced from October 2001 through February 2002. These cars require replacement of the engine oil pump and as a precautionary measure, replacement of the connecting rod bearings. In addition, the engine control module will be programmed with the latest software, which includes improved cold start characteristics. We ask that you contact your authorized BMW center to arrange a service appointment to have this service action carried out. Your vehicle can still be driven with no immediate need to have the repairs carried out. The service action will take approximately one days work, however, the actual time will vary with center scheduling. BMW of North America, LLC, will cover all necessary repair costs related to this action as well as providing you with alternate transportation if necessary. After the service action is performed on your M car, a 1,200 mile break-in period must be observed. Do not exceed 5,500 engine rpm or 105 mph road speed during this period. Please observe your local & state maximum speed limits. " - This "service action" is being done by VIN number and generally effects 2002 M3's manufactured between October of 2001 and February 2002.

As all can see, no mention of WOT. That said, I know for a fact that I received explicit instructions to avoid full throttle. I had to do this procedure three times, whether WOT was deemed unnecessary for the last two, I honestly am not sure (17-18 years ago) but am willing to bet it was. I am NOT arguing the validity, merely the messenger.

[digger]

https://nam3forum.com/forums/filedata/fetch?id=42909

the context was in the amount of clearance used, its fairly straight forward that with larger clearances under during shock loads the supported area is less leading to higher contact stress and vice versa with minimal clearance.

It says nothing about break in creating a magically better finish like with rings which is visible with a profilometer as far as peaks, valleys and plateau.

think about it if you baby the engine the crank wont touch the bearing so how is it even going to break in? if you are trying to break in something the surfaces need to touch .

We wouldn't be having this discussion if the bearing manufacturers specified break in / running in / bedding in as part their procedures and installation guidelines as it would be black or white. yet if you want to find about ring break-in or cam breaking then you don't need to look too hard.

i'm still waiting for where it says you cant go WOT as part of the BMW rod bearing break-in . i expect them to say as as part of full engine break-in.

[Obioban]

Can you provide the link ? it may be in the context of a "sacrificial" coating that some use e.g. clevite tri armour. Otherwise why is there minmal clearance

https://nam3forum.com/forums/filedata/fetch?id=42909

[R60BBA]

Rod bearings (or head gaskets for that matter) do not require breaking in.

They are not pistons.

However, for peace of mind it may be worth breaking the engine in after a rod bearings service and dropping the oil after 1,200 miles.

[digger]

Can you provide the link ? it may be in the context of a "sacrificial" coating that some use e.g. clevite tri armour. Otherwise why is there minmal clearance

[Obioban]

If you are in the BMW says so therefore i will follow camp fair enough cant expect the average/lay person with zero technical understanding (and not interested in improving) to think much about this stuff but if you're an enthusiast don't pretend there's a technical reason for it just because BMW says to do it. The OP knows BMW says so.

It's better to understand (or try to) whats going on otherwise what will you do in life when there is no procedure. This is an enthusiast forum if you cant handle discussions and differing (informed) opinion then why are you posting in this thread? i'm all for people with alternate opinions but if you aren't prepared to be called out on them if they are flawed then..........BMW says so is not a valid opinion that adds anything useful to the discussion.

I'd give up on the bad analogies (should have used cartilage), the rod bearings will always wear out eventually if you use the engine as intended, even if you had a 6k redline they still wear out on automotive applications they are sacrificial parts. on other equipment they can outlast the equipment life when done properly

Here is a quote from the company that makes BMW's revised s65/s85 bearings (Glyco):

If the clearance is minimal there is good conformability between the bearing and crankshaft journal. This conformability is a result of material that is worn in some parts of the bearing in the order of magnitude of μms. This process leads to less local stress on the sliding layer, a better absorption of shock loads and less wear.

So there's your rod bearing break in benefit/what's going on.

[Tones]

i meant generic in that its clearly not a rod specific break-in, what does 100 mph have to do with rod bearings? So WOT is ok even though the loads on bearings at peak torque ~4900 rpm are just as high if not higher than the tensile loads > 5,500 rpm ?

If the bearings last 60,000-100,000 miles then the wear after 1,200 would be 1-2% of the wear which is negligible (its more likely nonlinear with accelerated wear at end of life so its negligible). the bearings are not abradeable you aren't waiting for them to self clearance or of for surfaces to bed into each other like other areas inside the engine.

i encourage people to think about things not blindly follow nonsense just because BMW says so. About the only think i'd do is run the oil and filter for a very short interval in case some crap got in during the change out so it gets flushed out.

This dude gets all his news from the youtubes😂😂😂

Sent from my Pixel 3 XL using Tapatalk

[digger]

So what’s your argument here? Earlier posts suggest that you’re against break in procedures but now you’re indifferent because there’s not enough evidence to suggest doing them anyways? So you’re telling me that these people that spend hours and hours analyzing oil content and other various rod bearing related items are wasting their time doing so, just because BMW doesn’t know how to build an engine right? Sounds like you should go work for BMW and engineer and build an engine of your own that’s N/A and revs to 8K and see how that works.

And good one, indeed. Bones can still break even after they have healed.

If you are in the BMW says so therefore i will follow camp fair enough cant expect the average/lay person with zero technical understanding (and not interested in improving) to think much about this stuff but if you're an enthusiast don't pretend there's a technical reason for it just because BMW says to do it. The OP knows BMW says so.

It's better to understand (or try to) whats going on otherwise what will you do in life when there is no procedure. This is an enthusiast forum if you cant handle discussions and differing (informed) opinion then why are you posting in this thread? i'm all for people with alternate opinions but if you aren't prepared to be called out on them if they are flawed then..........BMW says so is not a valid opinion that adds anything useful to the discussion.

I'd give up on the bad analogies (should have used cartilage), the rod bearings will always wear out eventually if you use the engine as intended, even if you had a 6k redline they still wear out on automotive applications they are sacrificial parts. on other equipment they can outlast the equipment life when done properly

[Icecream]

The misinformation being spread around is not needing to do a proper break in when even BMW recommends it. Think about it, would you apply full force on a broken bone right after they put on a cast?

They also recommend castrol, now shell. It could have also been insurance for them so if the bearings went again and the SA asked the customer "did you follow the break in procedure" it would provide a reason for BMW to not fix the issue for free a second time. Dealers and companies have done worse.
From a logical standpoint, it does not make sense to me to break them in. they don't need to seat, they don't increase in clearance and they are not supposed to come into contact with a perfectly machined crankshaft (even though they do, a little, over time). The lead is very soft compared to the crank and thus I would argue that one pass of the crank under load where it contacts the bearing is enough to deform (maybe not even remove any appreciable material) the bearing at that point and this probably happens thousands of times (in different areas of the bearing) before you replace the bearings anyway, well past the break-in period. Did I do it? Yes, but more so when I sell I can say yeah I did it and because it was easy enough (and because yeah, I don't build engines and might be overlooking something). YMMV.

[erickhoyos]

Just because BMW says something doesn't mean the underlying premise is factual, i mean they are the ones that screwed up rod bearing on a bunch of engines even post s54 so how much do you trust them anyway....

misinformation is "false or inaccurate information, especially that which is deliberately intended to deceive" such as saying BMW don't have a procedure. it is not false that you don't need to do the procedure because there is no technical basis for doing it, i mean the very procedure is inconsistent with protecting rod bearings.

yeah good one, you know bones heal over time right? after the 1200 miles there is no healing or improvement over time its all downhill from the first turn of the key

So what’s your argument here? Earlier posts suggest that you’re against break in procedures but now you’re indifferent because there’s not enough evidence to suggest doing them anyways? So you’re telling me that these people that spend hours and hours analyzing oil content and other various rod bearing related items are wasting their time doing so, just because BMW doesn’t know how to build an engine right? Sounds like you should go work for BMW and engineer and build an engine of your own that’s N/A and revs to 8K and see how that works.

And good one, indeed. Bones can still break even after they have healed.

[digger]

The misinformation being spread around is not needing to do a proper break in when even BMW recommends it. Think about it, would you apply full force on a broken bone right after they put on a cast?

Just because BMW says something doesn't mean the underlying premise is factual, i mean they are the ones that screwed up rod bearing on a bunch of engines even post s54 so how much do you trust them anyway....

misinformation is "false or inaccurate information, especially that which is deliberately intended to deceive" such as saying BMW don't have a procedure. it is not false that you don't need to do the procedure because there is no technical basis for doing it, i mean the very procedure is inconsistent with protecting rod bearings.

yeah good one, you know bones heal over time right? after the 1200 miles there is no healing or improvement over time its all downhill from the first turn of the key

[erickhoyos]

You may think you’re clever but I’m actually ok with people following the procedure just because it’s the procedure but not with spreading bs about why it’s needed as some kind of justification when there is no actual technical merit let alone a logical hypothesis for why it is needed . It’s spreading misinformation and there’s enough of that already

The misinformation being spread around is not needing to do a proper break in when even BMW recommends it. Think about it, would you apply full force on a broken bone right after they put on a cast?

[BearDeXPS]

just rip that shit

[digger]

105mph is to avoid the high loading on the engine necessary to overcome wind resistance at higher speed. WOT is also not allowed per BMW’s procedure.

The breakin I just read said nothing about wot just rpm 5500 iirc and speed 100 maybe there are multiple different ones

you can do 100mph with about 75hp which isn’t really a load (force) nor is it “much” for an m3.
Speeds limits are for driveline component breakin it’s not a specific rod thing as it’s a poor definition of operational loading for an engine unless you’re dealing with a heat input with a thermally sensitive part.
Engine loads come from torque ( cylinder pressure) and inertia (rpm) which are at different moments in “time” so power isn’t even a useful rating of a rod or the bearing.

[Obioban]

i meant generic in that its clearly not a rod specific break-in, what does 100 mph have to do with rod bearings? So WOT is ok even though the loads on bearings at peak torque ~4900 rpm are just as high if not higher than the tensile loads > 5,500 rpm ?

If the bearings last 60,000-100,000 miles then the wear after 1,200 would be 1-2% of the wear which is negligible (its more likely nonlinear with accelerated wear at end of life so its negligible). the bearings are not abradeable you aren't waiting for them to self clearance or of for surfaces to bed into each other like other areas inside the engine.

i encourage people to think about things not blindly follow nonsense just because BMW says so. About the only think i'd do is run the oil and filter for a very short interval in case some crap got in during the change out so it gets flushed out.

105mph is to avoid the high loading on the engine necessary to overcome wind resistance at higher speed. WOT is also not allowed per BMW’s procedure.