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

[jet_dogg]

If you guys are so smart about bearings, why don't you give BMW M engineers a ring and tell them they're full of shit. I'll watch.

This is one of my favorite type of fallacies. Reminds me of the shitty job coaching Dave Roberts does for the Dodgers and geniuses in the comments will say "oh well how come you're not a coach then!" etc haha.

[tnord]

If you guys are so smart about bearings, why don't you give BMW M engineers a ring and tell them they're full of shit. I'll watch.

you’re right, BMW has a great reputation for putting out reliable engines with no bearing issues whatsoever. how dare i question them.

[Jimbo's M]

This is one of my favorite type of fallacies.

Then educate us.

[Jimbo's M]

you’re right, BMW has a great reputation for putting out reliable engines with no bearing issues whatsoever. how dare i question them.

Not positive nor an excuse, but I believe BMW contracted bearings out.

[tnord]

BMW gave the specs to the mfg, including the acceptable tolerances. then either accepted the out of spec parts that were delivered or didn’t care enough to do a final check prior to or during assembly.

[Jimbo's M]

BMW gave the specs to the mfg, including the acceptable tolerances. then either accepted the out of spec parts that were delivered or didn’t care enough to do a final check prior to or during assembly.

Like I said, not making excuses. Just having a conversation...

[IamFODI]

Getting a bit spicy in here. Let's drink some milk / eat some rice and get back on topic.

[old///MFanatic]

Easy to just to forget what the dealer said except for one tiny detail in my case, I was still under full warranty even after the second bearing change. Doesn't matter what I think, doing it their way three times was brutal. So, the way I see it is either you do their way or face something effin' up that I would be liable for because the DME or whatever fibbed on me.

Well to be fair all the tens of thousands of us during that campaign were under warranty too.
I don’t think anyone is denying what the policy was from BMW then. I think the thread is about current policy or need for break-in. And according to post #56, BMW dealerships no longer demand the old break-in period after replacing S54 rod bearings. Which follows other major respected shops like Lang Racing who don’t have a break-in rod bearing requirement. Nor a soon after oil change.

[Jimbo's M]

Well to be fair all the tens of thousands of us during that campaign were under warranty too.

I was replying to members on this forum that may not have gone through this, not the original owners of the whole planet. I'm quite sure there can't be more than a handful here that have had original warranties, so I made the comment. Nothing more, nothing less. If all the hoops I jumped through were essentially meaningless, now after 19 years, I'll get over it.

[IamFODI]

And according to post #56, BMW dealerships no longer demand the old break-in period after replacing S54 rod bearings.

True, but nor do they have a full factory warranty commitment to deal with. Just the 2 years on the repair, no?

[JayVee]

Engineer here. These are hydro-dynamic bearings, meaning they rely on a high film strength in oil in order to lubricate the surface. No metal-to-metal contact should occur.. with that said, I recently changed my bearings with VAC moly-disulfide coated bearings and followed a break-in procedure of 1200 miles of no full throttle, no rev's past 4.5k. After that, I changed the oil again, and now have peace of mind. Is this necessary? probably not, but well worth it in my mind.

[jbfrancis3]

Engineer here. These are hydro-dynamic bearings, meaning they rely on a high film strength in oil in order to lubricate the surface. No metal-to-metal contact should occur.. with that said, I recently changed my bearings with VAC moly-disulfide coated bearings and followed a break-in procedure of 1200 miles of no full throttle, no rev's past 4.5k. After that, I changed the oil again, and now have peace of mind. Is this necessary? probably not, but well worth it in my mind.

Did you opt to check clearances with plasti-gauge?

[JayVee]

Did you opt to check clearances with plasti-gauge?

I did not. I choose to skip this step. I know some say it's very critical, however, I spoke in-depth to Calico (the coaters of the bearings), and the fact these bearings are made by Mahle/Clevite (the OE supplier) I was comfortable installing them without plasti-gauge.

[jbfrancis3]

I did not. I choose to skip this step. I know some say it's very critical, however, I spoke in-depth to Calico (the coaters of the bearings), and the fact these bearings are made by Mahle/Clevite (the OE supplier) I was comfortable installing them without plasti-gauge.

I think the over-arching message should be: (by the way the intended audience is persons who are about embark on a bearing replacement or have just completed one)

If you want peace of mind, check the clearances. If you want peace of mind on top of peace mind, also follow the former "break-in" procedure.

Any disagreement?

[Albino09]

Another engineer who has written several hundred TSBs for another OEM. Engineers write these bulletins along with a technical service writer who helps translate them for service technicians. They are then published into the network for technicians to access freely. Nobody else has any input into these documents from the technical aspect.

Recalls are another story, because they are managed by a separate team that specializes in those matters. Since this was not a recall per se, there is no reason to view the original service bulletin with skepticism. I can personally vouch for the fact that we are doing our best to fix the customer's car using safe and effective techniques and practices. Random engineers who don't give a F about engines don't end up in those roles. They care and they were trying to fix a quality issue.