Break-in Procedure

[digger]

Is everything okay at home? You wanna talk about some stuff? You seem a little upset at the fact that people genuinely care about treating their engines well rather than mash the throttle like a junkyard LS with no oil/coolant.

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

[erickhoyos]

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.

Is everything okay at home? You wanna talk about some stuff? You seem a little upset at the fact that people genuinely care about treating their engines well rather than mash the throttle like a junkyard LS with no oil/coolant.

[digger]

It's not generic. It's S54 specific. There is wear on the bearings after a few hundred miles whether you think there is or not. Leaning towards the side of who cares isn't the way we should treat our cars. I wouldn't treat a customers car this way. Just because most engines don't do this or even need it doesn't mean ours should be lumped in the same pile. You can disagree with the TSB but I wouldn't advise people ignore it.

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.

[enjoy_m3]

Bmw also says to do the break in procedure as part of the rod bearing replacement SIB

You are correct, I wasn't dismissing bearings. Only pointing out other aspects to consider.

[Arith2]

the wear pattern should not be there after 1,200 miles they are supposed to look mint. the clearances may be tight will still be tight after the break in as they dont get worn away/relieved to the right clearance .....so what does the break in achieve? hint: nothing its just a generic procedure

It's not generic. It's S54 specific. There is wear on the bearings after a few hundred miles whether you think there is or not. Leaning towards the side of who cares isn't the way we should treat our cars. I wouldn't treat a customers car this way. Just because most engines don't do this or even need it doesn't mean ours should be lumped in the same pile. You can disagree with the TSB but I wouldn't advise people ignore it.

[digger]

Rod bearings have wear patterns. I believe it says dont exceed like 50% or 60% load along with the other stuff. I don't really think it matters about load variation, just that a certain amount isn't exceeded. Most of my break in miles were highway miles. Our engines are known to have tighter clearances so it'd be better to heed the warning. BMWs in general have tight clearances so do follow the TSB. It's not just talking about engines break in, it specifically refers to bearings needing 1200 miles.

the wear pattern should not be there after 1,200 miles they are supposed to look mint. the clearances may be tight will still be tight after the break in as they dont get worn away/relieved to the right clearance .....so what does the break in achieve? hint: nothing its just a generic procedure

[Arith2]

Rod bearings have wear patterns. I believe it says dont exceed like 50% or 60% load along with the other stuff. I don't really think it matters about load variation, just that a certain amount isn't exceeded. Most of my break in miles were highway miles. Our engines are known to have tighter clearances so it'd be better to heed the warning. BMWs in general have tight clearances so do follow the TSB. It's not just talking about engines break in, it specifically refers to bearings needing 1200 miles.

[digger]

once the oil is hot drive it like you stole it

[Jimbo's M]

Thats not the break-in procedure.

Concur. Should be driven in conditions more indicative of load variance on the motor...other than WOT that is.

[Estoril]

If anything now is the perfect time to log in the break in miles since traffic is light due to the pandemic. Drive about 250 highway miles per day every other day and you'll hit the 1,200 mark pretty quickly.

Thats not the break-in procedure.

[cbean]

Currently in the break in period process from my ROD bearing install.

One point of view was track only cars that go from shop to track . . . No break in period

Mine is not a track car ( hopefully it will see a day or two ) . . . I the Nick_P said it best . . . "certainly doesn't hurt and for peace of mind"

[Nick_P]

I followed the break-in procedures as well...certainly doesn't hurt and for peace of mind

[2004LSB]

If anything now is the perfect time to log in the break in miles since traffic is light due to the pandemic. Drive about 250 highway miles per day every other day and you'll hit the 1,200 mark pretty quickly.

[Jimbo's M]

BMW suggests not exceeding 5,500 RPM or 105MPH for 1,200 miles.

You forgot no WOT as well...

[Obioban]

It's really up to your confidence on the rebuild. Did you replace the piston/rings/cams/followers? Those are the main areas requiring good break in when new.

Bmw also says to do the break in procedure as part of the rod bearing replacement SIB