Good video on engine break in, including the usefulness of bearing break in

[bigjae46]

Don’t think 1200 miles is necessary but would definitely put some miles on it and then do an oil change before going all out.

[Obioban]

Shiba dude on the internet being skeptical
or

90 year old Chevy engineer saying "you gotta bed in them surfaces!"

A) aka the engineers of the most powerful NA V8 ever, probably a forever record.

B) also the s54 engineers 😜

[jet_dogg]

Shiba dude on the internet being skeptical
or

90 year old Chevy engineer saying "you gotta bed in them surfaces!"

Shiba du can believe whatever he wants, even that he identifies as an animal.

That isn't the argument you think it is, so I'll take 90 yo du's wisdom and experience.

[Arith2]

The 1200 miles isn't S54 specific. Actually modern M cars are coming out with reduced power and redline until 600 miles and it recommended to avoid launch control or maximum load until after the break in. This recommendation applies to the S68 and S58. Beat your crap up if you choose, it's yours. I would not and did not after my rod bearings.

I always love hearing the stupid arguments that rod bearings don't touch any metal therefore they don't wear. It's like saying transmissions come with lifetime fluid.

[digger]

i was really expecting the GM guy to say beat on it from the get go, im sure his employer would like that....

not all bearings are created equal and modern bearings are quite a bit different to the stuff sold in the 90's just ring materials and coatings and the cylinder wall finishes are vastly different

personally by the time you first start and getting everying toasty as youre supposed to do before beating on it the asperturites will be gone. plus on a used engine the crank is broken in not fresh off the grinder with remaining fuzz

[bigjae46]

The 1200 miles isn't S54 specific. Actually modern M cars are coming out with reduced power and redline until 600 miles and it recommended to avoid launch control or maximum load until after the break in. This recommendation applies to the S68 and S58. Beat your crap up if you choose, it's yours. I would not and did not after my rod bearings.

That's a common misconception. M cars come with stock programming from the start. The car is programmed during the break in service but the only software change is to update the maintenance intervals so the break-in service reminder doesn't keep coming on.

[cobra]

The 1200 miles isn't S54 specific. Actually modern M cars are coming out with reduced power and redline until 600 miles and it recommended to avoid launch control or maximum load until after the break in. This recommendation applies to the S68 and S58. Beat your crap up if you choose, it's yours. I would not and did not after my rod bearings.

I always love hearing the stupid arguments that rod bearings don't touch any metal therefore they don't wear. It's like saying transmissions come with lifetime fluid.

My question is...
What happens at 600 miles that suddenly makes it okay to thrash on? What about 597 miles? Would that have been okay? Does this seemingly arbitrary number apply to all the components in the vehicle or just some of them? Or perhaps... none of them, and the 600 miles is to break in the driver.

I would like to see a list of break-in durations for each component on the vehicle. How many of those happen within the first 5 minutes of operation, and how many actually take a certain amount of time/mileage to achieve? How many of those are things that can be noticeably affected by driving behavior?

Off the top of my head, the only one that comes to mind is the brakes. They do not function properly when new and need to be bedded in. But brakes are purpose built to wear out and create friction. Quite the opposite of bearings/cams/gears and all the other internal parts we're talking about.


As you can see I have way more questions than answers, though I'm still skeptical about break-in periods because there hasn't been any good data provided.

[bigjae46]

My question is...
What happens at 600 miles that suddenly makes it okay to thrash on? What about 597 miles? Would that have been okay? Does this seemingly arbitrary number apply to all the components in the vehicle or just some of them? Or perhaps... none of them, and the 600 miles is to break in the driver.

I would like to see a list of break-in durations for each component on the vehicle. How many of those happen within the first 5 minutes of operation, and how many actually take a certain amount of time/mileage to achieve? How many of those are things that can be noticeably affected by driving behavior?

Off the top of my head, the only one that comes to mind is the brakes. They do not function properly when new and need to be bedded in. But brakes are purpose built to wear out and create friction. Quite the opposite of bearings/cams/gears and all the other internal parts we're talking about.


As you can see I have way more questions than answers, though I'm still skeptical about break-in periods because there hasn't been any good data provided.

I think BMW used the 1200 mile figure as a super safe number that would cover 99.99999% of the engines they build. The actual break in would vary engine to engine. So we choose a number that would cover a large majority of the situations...statistics.

My theory..at a minimum, there is a heat cycling that needs to occur since parts will have different expansion and contraction under heating and cooling. So a break in makes sense to get a heat cycle to make everything play well together. May need a couple of heat cycles. I think that is a bigger part of a break in that actually wearing parts in.

[Arith2]

My question is...
What happens at 600 miles that suddenly makes it okay to thrash on? What about 597 miles? Would that have been okay? Does this seemingly arbitrary number apply to all the components in the vehicle or just some of them? Or perhaps... none of them, and the 600 miles is to break in the driver.

I would like to see a list of break-in durations for each component on the vehicle. How many of those happen within the first 5 minutes of operation, and how many actually take a certain amount of time/mileage to achieve? How many of those are things that can be noticeably affected by driving behavior?

Off the top of my head, the only one that comes to mind is the brakes. They do not function properly when new and need to be bedded in. But brakes are purpose built to wear out and create friction. Quite the opposite of bearings/cams/gears and all the other internal parts we're talking about.


As you can see I have way more questions than answers, though I'm still skeptical about break-in periods because there hasn't been any good data provided.

A combustion chamber produces well over 1000psi. That force is concentrated through a rod to the crankshaft. There's a few thousands pounds of pressure there.

Think about what's between the rod and the crank. A rod bearing and oil. If the Bearing touches the journal, you have a very bad day. The highest stressed part of an engine are the rods and the bearings. What makes the need a break in is the slight manufacturing differences between the bearing and the journal. The surfaces will need to wear together to achieve and even flow of oil in such a high stress environment. This also produces less friction and heat.

Heat and contracting may also settle everything in. These clearances can't be felt or seen. They going subtle but if you what, what the engineers have deemed proper wear, stick the designers' recommendations rather than anecdotal nonsense. You may get perfectly machined bearings and a break in is irrelevant. You may not.

I had a C8 lockup while I driving it at 602 miles because the break-in procedure wasn't followed. Some old guy owned it. He was from the villages here in FL. The tires were already almost heat cycled. Rod bearings welded themselves to the crank.

They don't just come up with some random number. There at test cars that get driven and torn apart afterwards to examine everything. They take the time to verify the practical application. The safe number is 1200. Ideally all the parts in every engine should be worn in. It's a very safe number for the masses. One engine may need 762 miles and another 1051 miles. Rod bearings are part of that running-in as it is called by BMW.

[jet_dogg]

It seems some people would rather be sorry than safe, just let them be.

[Feffman]

When my current S54 was rebuilt for the race car (different environment I realize but it's essentially a stock build) the builder said brake it in with 500 miles of varied speed/RPM driving below a certain RPM (can't remember the number now) and break-in oil. Since I don't have cats on my M3, I used Lucas Oil 20W-50 high-zinc break in oil (https://lucasoil.com/pdf/TDS_SAE20Break-InOils.pdf)

After 500 miles sneaking around on roads at wee hours of the morning, I dropped the break-in oil and swapped to a 10W-60 synthetic. My car lives above 8,000RPM and my Blackstone oil analysis every other change still shows all is well almost 5 years later. I don't know if it was the break in procedure, continuous oil changes every second event or what, but when the new race motor is done, I'm planning the same break-in procedure.

Feff

[enjoy_m3]

Man can of worms opened. LOL.

I'd put it in my pointless .02 cents but let's just say I agree with some builders such as Jay from real street, companies like Total Seal Piston rings and some really good machine shops (race engine builders) if anyone cares to educate themselves on break in procedures since there's lots of opinions. The vid definitely would work for new cars. It's when you're rebuilding the engine where the opinions get everywhere, especially when it's a performance engine.

Too many variables. Let's not forget the person who assembles the engine is also the variable.

[cobra]

I think BMW used the 1200 mile figure as a super safe number that would cover 99.99999% of the engines they build. The actual break in would vary engine to engine. So we choose a number that would cover a large majority of the situations...statistics.

My theory..at a minimum, there is a heat cycling that needs to occur since parts will have different expansion and contraction under heating and cooling. So a break in makes sense to get a heat cycle to make everything play well together. May need a couple of heat cycles. I think that is a bigger part of a break in that actually wearing parts in.

I am not sure I understand the heat cycle theory either. If I started up my brand new S54 and drove it 1200 miles without ever shutting it off, is that engine less broken in than if those 1200 miles consisted of 20 warmup/cooldown cycles? What will be different about the two engines on a component level?

I wouldn't be surprised to see more wear particles in the stop/start engine because the likelihood of metal-on-metal contact is much higher during startup due to the brief moment the hydrodynamic oil layers haven't built up. That's more about stop-start cycles, and less to do with heat though.

A combustion chamber produces well over 1000psi. That force is concentrated through a rod to the crankshaft. There's a few thousands pounds of pressure there.

Think about what's between the rod and the crank. A rod bearing and oil. If the Bearing touches the journal, you have a very bad day. The highest stressed part of an engine are the rods and the bearings. What makes the need a break in is the slight manufacturing differences between the bearing and the journal. The surfaces will need to wear together to achieve and even flow of oil in such a high stress environment. This also produces less friction and heat.

Heat and contracting may also settle everything in. These clearances can't be felt or seen. They going subtle but if you what, what the engineers have deemed proper wear, stick the designers' recommendations rather than anecdotal nonsense. You may get perfectly machined bearings and a break in is irrelevant. You may not.

I had a C8 lockup while I driving it at 602 miles because the break-in procedure wasn't followed. Some old guy owned it. He was from the villages here in FL. The tires were already almost heat cycled. Rod bearings welded themselves to the crank.

They don't just come up with some random number. There at test cars that get driven and torn apart afterwards to examine everything. They take the time to verify the practical application. The safe number is 1200. Ideally all the parts in every engine should be worn in. It's a very safe number for the masses. One engine may need 762 miles and another 1051 miles. Rod bearings are part of that running-in as it is called by BMW.

"If the Bearing touches the journal, you have a very bad day." I agree!

So the bearing doesn't touch the journal, then how will it ever break in?

The only time I think a rod bearing has potential to touch the journal is during initial startup after a long time sitting, and the oil has had time to seep out. Or in the case of the S54, there is a design issue that causes it to wear out (at high RPM's we think?) which is a slow progressive failure and not something that happens during break-in.

https://www.youtube.com/watch?v=MlmHOMm9gow

[Slideways]

Man can of worms opened. LOL.

I'd put it in my pointless .02 cents but let's just say I agree with some builders such as Jay from real street, companies like Total Seal Piston rings and some really good machine shops (race engine builders) if anyone cares to educate themselves on break in procedures since there's lots of opinions. The vid definitely would work for new cars. It's when you're rebuilding the engine where the opinions get everywhere, especially when it's a performance engine.

Too many variables. Let's not forget the person who assembles the engine is also the variable.

For a new/refurb engine, I think BMW's break-in recommendation has faired pretty well. The S54 doesn't burn much oil, if any and they easily reach over 100k street miles. Now to know what break-in oil they used for the first 1200 miles or was it just 5w-30 or 10w-60.

[Obioban]

For a new/refurb engine, I think BMW's break-in recommendation has faired pretty well. The S54 doesn't burn much oil, if any and they easily reach over 100k street miles. Now to know what break-in oil they used for the first 1200 miles or was it just 5w-30 or 10w-60.

A decade ago on M3forum, I did a poll— and there was a strong correlation between breaking in the engine per BMW’s spec and not burning oil (and the inverse— going hard from day 1 and oil burning).