Rod Bearing Break-in (hint: there isn't a need)

[old///MFanatic]

It's been almost twenty years since I went through this, but considering I did it not once, but three times, I imagine I remember it correctly. Whether no WOT was actually for all three times, that I can't be sure of but would imagine that it was.

I didn't have that listed on mine. It's also nowhere on all my receipts/records. I can't say what your particular dealership said but it still doesn't appear a standard BMW statement from searching documents. The thing with "Warnings signs" is they are something that are highly visible and easily found. Wouldn't be much of a "cover our ass" statement if it's not highly visible and found in documents to public right? *But just because I haven't been able to find it anywhere doesn't mean it's not out there right lol. One would have to imagine no WOT if those other warnings are listed in all fairness.

[Jimbo's M]

For what it’s worth, BMW states to observe the engine Break-In” instructions. But then also states:
“Engine oil service is not required after completion of the engine break-in period.”

I'm all but certain my oil was changed after all three. Whether they were obligated or not, don't remember.

[Jimbo's M]

It’s been a while but don’t recall seeing BMW write “No full throttle acceleration”. My SIB 110404 doesn’t say that, nor did my “Break in Procedure” window sticker. Curious was this added later somewhere?

It's been almost twenty years since I went through this, but considering I did it not once, but three times, I imagine I remember it correctly. Whether no WOT was actually for all three times, that I can't be sure of but would imagine that it was.

[old///MFanatic]

What is the harm in breaking in, and changing the oil after 1K?

For what it’s worth, BMW states to observe the engine Break-In” instructions. But then also states:
“Engine oil service is not required after completion of the engine break-in period.”

[old///MFanatic]

Necessary or not, BMW had three requirements with the new bearings:
No full throttle acceleration..
Do not exceed 5500RPM..
Do not exceed 105mph..

It’s been a while but don’t recall seeing BMW write “No full throttle acceleration”. My SIB 110404 doesn’t say that, nor did my “Break in Procedure” window sticker. Curious was this added later somewhere?

[Arith2]

This post got in by mistake. The next one is what I wanted to say.

Ah ok. I missed the no full throttle but that makes sense too. What's the point of a break in if you're putting max load on your engine? Thanks for adding that because that's also quite important.

[Jimbo's M]

I know, posted the TSB. He's just right about the mph. So in reality there's just two. 5500rpm and 1200 miles.

This post got in by mistake. The next one is what I wanted to say.

[Arith2]

There were three requirements with the new bearings

I know, posted the TSB. He's just right about the mph. So in reality there's just two. 5500rpm and 1200 miles.

[Jimbo's M]

For the mile an hour, I was thinking 105 may have been at 5500rpm. I'm thinking 5th. It's been a long time since I've driven my M3. 105mph doesn't matter at all for bearings. Break in is different than initial clearance. If you have an issue with that, well, break in ain't gonna help.

Necessary or not, BMW had three requirements with the new bearings:

No full throttle acceleration..

Do not exceed 5500RPM..

Do not exceed 105mph..

I didn't argue, I just did it.

[Arith2]

Corporate training materials are the final forms they take, regardless of special names or special audiences. Sure, the content may originate from engineers tasked with fixing an issue. But a stream of conscious engineering thought does not land on a piece of paper and get broadcasted to dealerships worldwide. My point is everything goes through various checkpoints, as with anything in Corporatia. In this example, if engineers were truly left to their own devices? There would be steps to measures clearances, and no MPH spec because that means nothing.

I have nothing to gain here. I said there is not a need; I did not say don't follow them. It is good idea to follow all TSBs and associated procedures. It was helpful for someone to post the TSB itself so others searching can see the resources so thanks.

But I am biased towards my own thoughts, crazy as that may sound. I'd rather discover a clearance issue immediately than float through suspended reality for 1,500 miles...

Ultimately, people can choose what they want to do. That being said, it's highly advisable to follow a procedure that makes perfect sense. I really think that would still be there whether it went through corperate or came directly from engineers.

For the mile an hour, I was thinking 105 may have been at 5500rpm. I'm thinking 5th. It's been a long time since I've driven my M3. 105mph doesn't matter at all for bearings. Break in is different than initial clearance. If you have an issue with that, well, break in ain't gonna help.

[Desert_M3]

What is the harm in breaking in, and changing the oil after 1K?

No harm at all. Maybe it needs to be done, maybe it doesn't. I'm not willing to take that chance though.

[Flat-Six]

What is the harm in breaking in, and changing the oil after 1K?

[jbfrancis3]

TSBs are written by engineers. The rod bearing TSB says a break in period is required after replacing rod bearings.

Corporate training materials are the final forms they take, regardless of special names or special audiences. Sure, the content may originate from engineers tasked with fixing an issue. But a stream of conscious engineering thought does not land on a piece of paper and get broadcasted to dealerships worldwide. My point is everything goes through various checkpoints, as with anything in Corporatia. In this example, if engineers were truly left to their own devices? There would be steps to measures clearances, and no MPH spec because that means nothing.

I have nothing to gain here. I said there is not a need; I did not say don't follow them. It is good idea to follow all TSBs and associated procedures. It was helpful for someone to post the TSB itself so others searching can see the resources so thanks.

But I am biased towards my own thoughts, crazy as that may sound. I'd rather discover a clearance issue immediately than float through suspended reality for 1,500 miles...

[Arith2]

I wouldn't doubt a TSB over the chaos in 2003-2004. There is simply not even wear on bearings. The rods are not moving in a perfect circle. They push at certain points and have no load at others in the same 180°. Heck, they even move sideways sometimes. My previous bearings are clear evidence of that. Theory is nice but in reality, the TSB is solid advice. If you have a race engine, 1200 miles is absolutely unreasonable. Idle it for a bit and send it. It's a race engine and something will probably fail before something as robust as the bearings.

Our M3s are not dedicated track cars. We want longevity out of them. BMW isn't sponsoring us new engines and we are invested in our vehicles. Don't write off something that can determine whether your bearings last 50k miles or 150k. They absolutely do it. Some spin bearings long before that. Like me at 71k.

I'm pretty annoying that a simple disregard of physics is happening. Engine theory says bearings don't wear because rods never touch. Bs.

[Jimbo's M]

Remember this was written during the chaos around 2003-2004 .

It was earlier than that. The very first year model was suspect, then the 'service action', it was never a 'recall', started. My car is a 12/01 build, and just months later it was in getting new bearings. Then it was determined that that batch was bad as well. In again I went. By ~4/02 builds they figured they got it right. I guess so, I've been on these since then.