YAET: Breaking in an engine

[jagec]

Generally the manufacturer will tell you to run it really gently for the first hundred miles or so, not exceeding a certain RPM, and certainly not lugging the engine or running at a constant speed. However, various sites such as these seem to advocate a different methodology...where the engine is warmed up, and then run hard to seat the piston rings. The oil is changed shortly thereafter (and long before the factory recommended first-change).

So...are the manufacturers just writing conservative procedures so that Average Joe can more-or-less follow them without screwing up the engine? Or are the web authors just making stuff up that will kill your engine? Intuitively, I would have to agree that it's ridiculous to leave the break-in oil in the engine for as long as the recommendations allow...it seems to me that your first oil change would be better between 50 and 100 miles, not 500 up to freakin' 2500 like some manufacturers recommend.

Am I wrong? What do *you* think about engine break-in?

 

[Drakkon]

I'd do what the manf tells me before i'd attempt something that i read on the internet...

 

[amish]

Originally posted by: Drakkon
I'd do what the manf tells me before i'd attempt something that i read on the internet...

same, but i was a little weirded out when i didn't have to change my oil until 7K miles on my civic

 

[Trikat]

If you are buying a pretty powerful new car right off of the lot, chances are it has been "test driven" pretty hard already.
I've seen dealers and people who test drive cars floor the car repeatedly and cruise at pretty high speeds.

If you have the money to buy a brand spanking new car it is probably ideal to change the oil more frequently at the beginning of your car's life.

(I hate typing on this lappy so i'm not going back to fix errors.)

 

[fbrdphreak]

I've never heard of having to seat the piston rings on a new car, only if you change them yourself later.

When I buy a new car I plan on babying it for a thousand miles or so, unless the mfr recommends longer.

When my gf bought her new Civic, they said just drive it like normal right off. "Modern engines" don't need break-in is what they said. I'd say they're just asking you to wear it sooner, but the dealer they bought it from offered a 100K mile engine/transmission warranty if you do all regular maintenance there (with free oil changes).

 

[Baked]

And you wonder why VW cars have so many problems. Their manual suggests 1st oil change at some ridiculously high milage; something like 50K. WTF! I don't recall the exact number, but that's what my friend told me about the new beetle his sister bought.

1st oil change at 100 miles? WTF?! My car has a sticker on windshield that says 5K for oil change. I'm gonna put some mobile 1s in there at 2500.

I drove the car like I normally do during break in.

 

[MrWizzard]

I think you shouold get a Porsche, they come pre-broken in. I think BMW does it too, not sure though.

They usually run a little diff oil in the break in period to "clean out the engine" I know it sounds weird since it's new but if you do a little reasearch you will understand.

To be safe I would do what manufactureer says.

 

[jagec]

Originally posted by: Drakkon
I'd do what the manf tells me before i'd attempt something that i read on the internet...

Normally I'd agree, but (drawing a parallel from the computing world) sometimes manufacturers do some incomplete or flat-out wrong things, designed to keep the stupidest of their customers from screwing up, but totally crippling performance for people who know what they're doing.

I guess the real thing for me is the oil change...why would I leave oil filled with metal filings in my engine for thousands of miles?

 

[Albis]

i just got an acura tsx and acura told me they have special chemicals in their original oil that should stay in the car for awhile. they said it's a special formula and don't worry about changing your oil too soon.

 

[nakedfrog]

Originally posted by: Baked
And you wonder why VW cars have so many problems. Their manual suggests 1st oil change at some ridiculously high milage; something like 50K. WTF! I don't recall the exact number, but that's what my friend told me about the new beetle his sister bought.

I'd have to see some proof before I'd be willing to believe that. I think either your friend or his sister is wrong and is going to blow the engine.

 

[Apex]

Originally posted by: jagec
Generally the manufacturer will tell you to run it really gently for the first hundred miles or so, not exceeding a certain RPM, and certainly not lugging the engine or running at a constant speed. However, various sites such as these seem to advocate a different methodology...where the engine is warmed up, and then run hard to seat the piston rings. The oil is changed shortly thereafter (and long before the factory recommended first-change).

So...are the manufacturers just writing conservative procedures so that Average Joe can more-or-less follow them without screwing up the engine? Or are the web authors just making stuff up that will kill your engine? Intuitively, I would have to agree that it's ridiculous to leave the break-in oil in the engine for as long as the recommendations allow...it seems to me that your first oil change would be better between 50 and 100 miles, not 500 up to freakin' 2500 like some manufacturers recommend.

Am I wrong? What do *you* think about engine break-in?

I think it's interesting too, that virtually every engine builder will tell you to do a relatively hard break in.

I think it's a matter of priorities.

If you break the engine in hard, there's a marginally higher chance of near immediate catastrophic engine failure, something that would require replacement of the engine or major parts of it. Though the percentage is very low, it's important (IMHO) because:

1. Engine builders and race mechanics don't tend to care about this. They build relatively few engines and want the most performance out of those engines. Chances are, this won't affect them.

2. Manufacturers do care about this because it's expensive for them to replace these things (which would, of course, be under warranty period), and is really bad for customer perceptions.

I've run pretty much done a hard brake in on all of my cars except for the one which the manufacturer specifically stated they would void the warranty.

 

[notfred]

I love all the concrete evidence behind these types of discussions. You know, like the explanation of how "running hard" (definition of what that means, exactly?) helps to seat the piston rings differently than babying the car.

Seating the piston rings essentially consists of wearing down the inside of the cylinder and the outside edge of the piston ring until the fit perfectly inside one another. I'd love to hear the explanation of why trying to do this faster is so much better than doing it slowly. I guess you get slightly better performance and slightly lower oil consumption early on, but you still have to go through the same number of revolutions of the crankshaft to get to that point.

 

[jagec]

Originally posted by: notfred
I love all the concrete evidence behind these types of discussions. You know, like the explanation of how "running hard" (definition of what that means, exactly?) helps to seat the piston rings differently than babying the car.

Seating the piston rings essentially consists of wearing down the inside of the cylinder and the outside edge of the piston ring until the fit perfectly inside one another. I'd love to hear the explanation of why trying to do this faster is so much better than doing it slowly. I guess you get slightly better performance and slightly lower oil consumption early on, but you still have to go through the same number of revolutions of the crankshaft to get to that point.

I'm not totally sold on that part of it, but I question why the manufacturers don't tell you to change your oil sooner, since you've been loading it down with metal from the break-in process.

As for seating the piston...running it "hard" would create higher pressures inside the cylinder, thus pushing the rings more firmly against the cylinder wall during the power stroke. Whether this is a good or bad thing is up for debate, but it will take fewer revolutions of the crank to wear the rings and cylinders against each other.

 

[axnff]

Originally posted by: notfred
I love all the concrete evidence behind these types of discussions. You know, like the explanation of how "running hard" (definition of what that means, exactly?) helps to seat the piston rings differently than babying the car.

Seating the piston rings essentially consists of wearing down the inside of the cylinder and the outside edge of the piston ring until the fit perfectly inside one another. I'd love to hear the explanation of why trying to do this faster is so much better than doing it slowly. I guess you get slightly better performance and slightly lower oil consumption early on, but you still have to go through the same number of revolutions of the crankshaft to get to that point.

Supposedly, the reason this works is that after the first several hundred miles, the cylinders (or cylinder liners in an aluminum block) have hardened enough that they will no longer deform along with the rings. IIRC, the rings themselves are made of very hard (high molybdenum, I believe) steel and won't actually wear as much as the cylinder wall.

Substantial anecdotal evidence exists in that machinists find that used engine blocks are harder to work with than a new block from the same line.

They way I've heard it said is that a hard break-in will help engine power (better match between the ring and the bore) with more blow-by and oil consumption over the life of the motor. OTOH, a softer break-in should result in less oil consumption (the rings will fit the bore more snugly) and blow-by - theoretically permitting longer rebuild intervals or at least longer oil-change intervals.

 

[dnuggett]

Originally posted by: MrWizzard
I think you shouold get a Porsche, they come pre-broken in. I think BMW does it too, not sure though.

They usually run a little diff oil in the break in period to "clean out the engine" I know it sounds weird since it's new but if you do a little reasearch you will understand.

To be safe I would do what manufactureer says.

BMW recommends an oil change every 15,000 miles for our car. The car's computer system is set to that as well.

 

[BatmanNate]

Usually when I rebuild a motor I'll run it for about an hour idling with the heat blowing, change the oil, drive gently for 500 miles, change the oil, then build up to normal driving over a couple weeks. I do notice the gas mileage improve over a couple weeks too, I'm not sure if this is from the decreased friction in the cylinders or other factors. This has worked well for me, great compression and no noticable blowby on the last one I did in my truck.

 

[SampSon]

These sites seem to be focusing on sport bikes used for racing. Sport bikes are regularly run at much higher rpm and compression levels than your average car.

Obviously the manufacturer is going to go for the conservative procedures. Do you think they would advocate, in print, that when you buy a new car you should run it hard on public roads in order for it to work best? Sounds like a law suit waiting to happen.

In my opinion the normal everyday commuter car isn't going to benefit from having a "hard" break-in.

 

[thedarkwolf]

I just finished rebuilding the engine in my turbo caravan pics and am using the beat on it method. I let it idle to full temp, changed the oil, and have been driving it fairly hard for 80 miles sofar. I'm just running 8psi instead of the normall 18psi of boost for the first 1k miles or so. Plently of full throttle pulls and engine braking when I get a chance. I'll change the oil again at around 300 or 400 miles.

 

[Eli]

Originally posted by: notfred
I love all the concrete evidence behind these types of discussions. You know, like the explanation of how "running hard" (definition of what that means, exactly?) helps to seat the piston rings differently than babying the car.

Seating the piston rings essentially consists of wearing down the inside of the cylinder and the outside edge of the piston ring until the fit perfectly inside one another. I'd love to hear the explanation of why trying to do this faster is so much better than doing it slowly. I guess you get slightly better performance and slightly lower oil consumption early on, but you still have to go through the same number of revolutions of the crankshaft to get to that point.

When you drive the engine harder, the piston rings are cammed against the bore harder. That's the reasoning behind it.

Remember that they don't just seal the bore with spring pressure. Compression and power stroke forces are allowed behind the ring, forcing it against the bore.

Edit: I have always been a believer of the soft breakin method... One day, I hope to have enough money to run some tests of my own.

 

[Iron Woode]

I used a can GM EOS when I rebuilt my Buick 350. Then varied the rpm from 2500 - 4000 rpm over a period of 20 mins or so. Then shut down the engine and changed out the oil and filtre.

Then ran it gently for a few hundred miles before beating on it. That was back in 1990. The car and engine is still running fine to this day.

 

[Apex]

Originally posted by: jagec

Originally posted by: Drakkon
I'd do what the manf tells me before i'd attempt something that i read on the internet...

Normally I'd agree, but (drawing a parallel from the computing world) sometimes manufacturers do some incomplete or flat-out wrong things, designed to keep the stupidest of their customers from screwing up, but totally crippling performance for people who know what they're doing.

I guess the real thing for me is the oil change...why would I leave oil filled with metal filings in my engine for thousands of miles?

Your oil filter takes the metal fillings out of the engine. If it doesn't, you have bigger problems.

 

[RU482]

Manufacturers do not specify how to "break in" a car, as far as I remember from the 3 or 4 new cars I bought

 

[Iron Woode]

Originally posted by: redly1
Manufacturers do not specify how to "break in" a car, as far as I remember from the 3 or 4 new cars I bought

most modern engines (in the last 15 years or so) are already broken in. Just drive your car responsibly.

 

[Apex]

Originally posted by: Iron Woode

Originally posted by: redly1
Manufacturers do not specify how to "break in" a car, as far as I remember from the 3 or 4 new cars I bought

most modern engines (in the last 15 years or so) are already broken in. Just drive your car responsibly.

Some do and some do not. For instance, BMW's M series all have specific break in requirements. Lotus does for the Elise (and even does an ECU dump at the 1000 mile service to double check you didn't violate the terms).

 

[BoomerD]

I've always taken it easy on a new engine for the first 500 miles, then doing an oil change with the same oil it comes from the factory with, then another at very 3000 mile interval. "Taking it easy"doesn't mean never driving fast, but rather, not hot-rodding, and varying RPM's instead of just setting the cruise at 65 and going all day.
Probably not necessary to change the oil so often with today's technology, but it's the way I learned, and will probably continue to do so. Oil is still relatively cheap, especially as compared to the costs associated with poor maintenance procedures...