I bought a new motorcycle today (brand new, odometer read 0) and about 3 hours into a VERY cold ride home, my numb extremities failed me. I missed a shift and redlined it pretty hard.
While everything seems fine, it got me wondering: apart from the obvious risk of instant catastrophic failure, what are the “later in life” repercussions of such abuse during the break in period, and how do they differ from abusing an engine later in its life?
In: 44
(This might be a bit too advanced for ELI5 but I’ll give it a go)
On one hand, break in periods are basically null and void with modern engines, as the manufacturer has already properly broken them in before delivering the vehicle. Apart from an early 1000km oil change or so, the end user rarely has to treat the car any differently from usual early in its life.
However, in the case of rebuilt engines where the pistons/rings/cylinder sleeves have been changed, the general consensus is that after it’s been warmed up you should hit the engine quite hard. The newly-honed and slightly abrasive cylinder walls wear the fresh piston rings down, creating a good seal that stops blow-by and excessive oil usage. While not much actual research has been done, a lack of engine load during this break in period does appear to contribute to both a less-than-ideal piston ring seal and allows glazing of the cylinder walls, both of which decrease performance and increase oil burning for the life of the vehicle.
Modern engines are made very very well to extremely tight tolerances. Once it’s up to heat for the first time, if something is going to break, it will break regardless of how hard you push the engine. (Flat tappet camshafts are an exception though).
(This might be a bit too advanced for ELI5 but I’ll give it a go)
On one hand, break in periods are basically null and void with modern engines, as the manufacturer has already properly broken them in before delivering the vehicle. Apart from an early 1000km oil change or so, the end user rarely has to treat the car any differently from usual early in its life.
However, in the case of rebuilt engines where the pistons/rings/cylinder sleeves have been changed, the general consensus is that after it’s been warmed up you should hit the engine quite hard. The newly-honed and slightly abrasive cylinder walls wear the fresh piston rings down, creating a good seal that stops blow-by and excessive oil usage. While not much actual research has been done, a lack of engine load during this break in period does appear to contribute to both a less-than-ideal piston ring seal and allows glazing of the cylinder walls, both of which decrease performance and increase oil burning for the life of the vehicle.
Modern engines are made very very well to extremely tight tolerances. Once it’s up to heat for the first time, if something is going to break, it will break regardless of how hard you push the engine. (Flat tappet camshafts are an exception though).
All the parts in your engine are getting to know each other.
Think about a new friend or new roommate, when you first meet, everyone is tentative and courteous. After a while you get to know each other and settle into a groove. You don’t really want to apply high stress early in this relationship or it might come apart. If you do apply high stress, you’ll find out quickly a person’s true build quality.
Your engine is fine and is high build quality. Enjoy a lifelong relationship, maybe buy it some rose flavored oil and say sorry. It’ll go a long way.
All the parts in your engine are getting to know each other.
Think about a new friend or new roommate, when you first meet, everyone is tentative and courteous. After a while you get to know each other and settle into a groove. You don’t really want to apply high stress early in this relationship or it might come apart. If you do apply high stress, you’ll find out quickly a person’s true build quality.
Your engine is fine and is high build quality. Enjoy a lifelong relationship, maybe buy it some rose flavored oil and say sorry. It’ll go a long way.
All the parts in your engine are getting to know each other.
Think about a new friend or new roommate, when you first meet, everyone is tentative and courteous. After a while you get to know each other and settle into a groove. You don’t really want to apply high stress early in this relationship or it might come apart. If you do apply high stress, you’ll find out quickly a person’s true build quality.
Your engine is fine and is high build quality. Enjoy a lifelong relationship, maybe buy it some rose flavored oil and say sorry. It’ll go a long way.
Below is an exerpt of a response I made to a similar question in a different sub… It’s more focused on mileage before first oil change, but the same underlying rationale applies generally to how you’re supposed to treat the engine (gentle or not) during the “break-in period”…
There was a time when manufacturers specified high-additive (primarily zinc) oils from the factory to help properly bed-in the metal-on-metal surfaces (namely piston rings against cylinder walls) during the first few hundred miles. Essentially, the oil itself is acting as a very fine grinding compound, doing the final “fine tuning” of the metal-on-metal contact points. This is still the case with rebuilt engines.
There is a small body of die-hard wannabe-mechanics who swear a strict adherence to “break-in” miles is still needed on brand new engines, and funnily enough they fall into two very different camps. One side swears you MUST do the first oil change after just a few hundred miles because oil from the factory contains too many abrasive additives and going beyond that will just cause added wear — again, they’re going off information that was true maybe in the 70s and 80s or based off of rebuilt engine recommendations. The other side swears you should leave the factory oil in for as long as possible (up to the recommended service interval) because the additive content, while helpful, isn’t high enough to properly bed-in the engine within a few hundred miles.
Both sides cite anecdotal “evidence” all day for why their method is right. “I always change my oil at 200 miles and my cars run great.” or “I leave my oil in until exactly when the manual says and my cars run great.”… Hopefully you can see why both are entirely problematic arguments: there are plenty of people on BOTH sides with no major issues!
Truth of the matter is that there’s actually very little evidence to suggest that factory-fill oil is different from anything you’d buy off the shelf, nor that one set of break-in “procedures” is conclusively linked to longer engine life in any statistically meaningful way. In fact, people who send their first-fill oil to labs for analysis generally find that the results fall right in line with “normal” oils. Meaning that it doesn’t really matter when you do your first oil change, as long as you aren’t exceeding the recommended service interval by too much. Do it early or wait until the computer says you need to, either way you’ll be fine. Generally speaking, if you care enough about your car to stress about the maintenance interval, that alone will probably get you the life you want out of your vehicle. Modern engines are built to very tight specifications and, barring any major design flaws, are going to easily surpass the life expectations of the ones your parents grew up with.
Below is an exerpt of a response I made to a similar question in a different sub… It’s more focused on mileage before first oil change, but the same underlying rationale applies generally to how you’re supposed to treat the engine (gentle or not) during the “break-in period”…
There was a time when manufacturers specified high-additive (primarily zinc) oils from the factory to help properly bed-in the metal-on-metal surfaces (namely piston rings against cylinder walls) during the first few hundred miles. Essentially, the oil itself is acting as a very fine grinding compound, doing the final “fine tuning” of the metal-on-metal contact points. This is still the case with rebuilt engines.
There is a small body of die-hard wannabe-mechanics who swear a strict adherence to “break-in” miles is still needed on brand new engines, and funnily enough they fall into two very different camps. One side swears you MUST do the first oil change after just a few hundred miles because oil from the factory contains too many abrasive additives and going beyond that will just cause added wear — again, they’re going off information that was true maybe in the 70s and 80s or based off of rebuilt engine recommendations. The other side swears you should leave the factory oil in for as long as possible (up to the recommended service interval) because the additive content, while helpful, isn’t high enough to properly bed-in the engine within a few hundred miles.
Both sides cite anecdotal “evidence” all day for why their method is right. “I always change my oil at 200 miles and my cars run great.” or “I leave my oil in until exactly when the manual says and my cars run great.”… Hopefully you can see why both are entirely problematic arguments: there are plenty of people on BOTH sides with no major issues!
Truth of the matter is that there’s actually very little evidence to suggest that factory-fill oil is different from anything you’d buy off the shelf, nor that one set of break-in “procedures” is conclusively linked to longer engine life in any statistically meaningful way. In fact, people who send their first-fill oil to labs for analysis generally find that the results fall right in line with “normal” oils. Meaning that it doesn’t really matter when you do your first oil change, as long as you aren’t exceeding the recommended service interval by too much. Do it early or wait until the computer says you need to, either way you’ll be fine. Generally speaking, if you care enough about your car to stress about the maintenance interval, that alone will probably get you the life you want out of your vehicle. Modern engines are built to very tight specifications and, barring any major design flaws, are going to easily surpass the life expectations of the ones your parents grew up with.
Worst stresses are high throttle with low rpm (high load). Momentarily hitting redline with a bad shift (probably 0 load) on an engine that’s already well warmed up probably did nothing. So I wouldn’t worry
Worst stresses are high throttle with low rpm (high load). Momentarily hitting redline with a bad shift (probably 0 load) on an engine that’s already well warmed up probably did nothing. So I wouldn’t worry
Below is an exerpt of a response I made to a similar question in a different sub… It’s more focused on mileage before first oil change, but the same underlying rationale applies generally to how you’re supposed to treat the engine (gentle or not) during the “break-in period”…
There was a time when manufacturers specified high-additive (primarily zinc) oils from the factory to help properly bed-in the metal-on-metal surfaces (namely piston rings against cylinder walls) during the first few hundred miles. Essentially, the oil itself is acting as a very fine grinding compound, doing the final “fine tuning” of the metal-on-metal contact points. This is still the case with rebuilt engines.
There is a small body of die-hard wannabe-mechanics who swear a strict adherence to “break-in” miles is still needed on brand new engines, and funnily enough they fall into two very different camps. One side swears you MUST do the first oil change after just a few hundred miles because oil from the factory contains too many abrasive additives and going beyond that will just cause added wear — again, they’re going off information that was true maybe in the 70s and 80s or based off of rebuilt engine recommendations. The other side swears you should leave the factory oil in for as long as possible (up to the recommended service interval) because the additive content, while helpful, isn’t high enough to properly bed-in the engine within a few hundred miles.
Both sides cite anecdotal “evidence” all day for why their method is right. “I always change my oil at 200 miles and my cars run great.” or “I leave my oil in until exactly when the manual says and my cars run great.”… Hopefully you can see why both are entirely problematic arguments: there are plenty of people on BOTH sides with no major issues!
Truth of the matter is that there’s actually very little evidence to suggest that factory-fill oil is different from anything you’d buy off the shelf, nor that one set of break-in “procedures” is conclusively linked to longer engine life in any statistically meaningful way. In fact, people who send their first-fill oil to labs for analysis generally find that the results fall right in line with “normal” oils. Meaning that it doesn’t really matter when you do your first oil change, as long as you aren’t exceeding the recommended service interval by too much. Do it early or wait until the computer says you need to, either way you’ll be fine. Generally speaking, if you care enough about your car to stress about the maintenance interval, that alone will probably get you the life you want out of your vehicle. Modern engines are built to very tight specifications and, barring any major design flaws, are going to easily surpass the life expectations of the ones your parents grew up with.
Latest Answers