Engine run in
- Thread starter atason
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Vincent Ng
Well-Known Member
Re: Engine run in
Run-in period should be about 1600km...and it is not advisable to rev your engine above 4000rpm
Cheers
atason;191891 said:Hi all, for brand new BMW car do we need to running in our new engine for how many km, hear that the rpm can't go above certain rpm for long period of times for long distance drive.
Please advice and feedback thank you in advance.
Run-in period should be about 1600km...and it is not advisable to rev your engine above 4000rpm
Cheers
Vincent Ng
Well-Known Member
Re: Engine run in
Actually i'm not sure if continental cars like BMW need to be run-in or not. Apparently, continental cars already have their engine break in when they're delivered to us....anyone can shed some light on this?
Actually i'm not sure if continental cars like BMW need to be run-in or not. Apparently, continental cars already have their engine break in when they're delivered to us....anyone can shed some light on this?
Azrielsc
Core Group Members
Re: Engine run in
Its a hard question to really answer. This question has been posted in numerous boards and there are no conclusive evidence between a hard breaking-in or a slow breaking-in. I'll rather lead on the side of caution and go with the slow breakin-in because remember that the car does not consist of solely the engine but there are the brakes, transmission, tires, etc etc that has to be broken-in as well.
Vincent Ng;192662 said:
Its a hard question to really answer. This question has been posted in numerous boards and there are no conclusive evidence between a hard breaking-in or a slow breaking-in. I'll rather lead on the side of caution and go with the slow breakin-in because remember that the car does not consist of solely the engine but there are the brakes, transmission, tires, etc etc that has to be broken-in as well.
centurion
Well-Known Member
Re: Engine run in
I've done my fair share of reading of the forums, and my understanding has been this:
1) Break-in mainly means, because your pistons and the cylinder linings are manufactured fresh to `as smooth as possible' but this is still not enough. Break in actually rubs the pistons and the cylinder walls in such a way that they MATCH each other to one order of magnitude (10X) better than fresh manufacture. The unique structures of each piston and cylinder wall pairs better.
2) During break in, too high piston speeds will make the scores and scratches bigger than optimal, and this will require even more break in time to equalize. In extreme cases it cannot be equalized. This will decrease the compression ratio.
3) Many many years ago, Mercedes Benz introduced a method called shot-preening of the pistons which reduced the break-in time. Then, Porsche introduced silicon into steel to form the cylinder lining further reducing the break-in time, which BMW and technical partners refined the process and called it Nicasil linings. The Japanese did their processes too but it is not well documented. All these reduce the break-in time. Honda with their NSX supercar manufactured their pistons and linings to such low tolerances that break-in time was greatly reduced.
4) Note that this is merely a reduction - but it is still impossible to manufacture pistons and linings to such a incredible precision so as to totally make break-in obsolete. We are ONE order of magnitude away from it, and even in the future, we will not achieve the precision required, merely reduce it.
I've done my fair share of reading of the forums, and my understanding has been this:
1) Break-in mainly means, because your pistons and the cylinder linings are manufactured fresh to `as smooth as possible' but this is still not enough. Break in actually rubs the pistons and the cylinder walls in such a way that they MATCH each other to one order of magnitude (10X) better than fresh manufacture. The unique structures of each piston and cylinder wall pairs better.
2) During break in, too high piston speeds will make the scores and scratches bigger than optimal, and this will require even more break in time to equalize. In extreme cases it cannot be equalized. This will decrease the compression ratio.
3) Many many years ago, Mercedes Benz introduced a method called shot-preening of the pistons which reduced the break-in time. Then, Porsche introduced silicon into steel to form the cylinder lining further reducing the break-in time, which BMW and technical partners refined the process and called it Nicasil linings. The Japanese did their processes too but it is not well documented. All these reduce the break-in time. Honda with their NSX supercar manufactured their pistons and linings to such low tolerances that break-in time was greatly reduced.
4) Note that this is merely a reduction - but it is still impossible to manufacture pistons and linings to such a incredible precision so as to totally make break-in obsolete. We are ONE order of magnitude away from it, and even in the future, we will not achieve the precision required, merely reduce it.
yendor
Well-Known Member
Re: Engine run in
The introduction of Shot peening was not to emhance the dimensions of manufactured products but rather to increase the durability of metals by removing microscopic "cracks" in metals that may lead to stress fractures under high loads such as turbo applications or >9000rpm speeds.
Nikasil was a new high silicon content steel that was harder than conventional materials that enabled cylinder liners to be manufactured thinner and boasted greater tolerance to thermal expansion. They were used together with molybedenum coated pistons to reduce friction. Honda was a great proponent of this and uses this technology in their type-R engines.
In MHO, no production manufacturer can run-in a car as it will consume too much fuel and man-hours just to run-in all the wearables (engine, transmission, driveline bearings, brakes) Usually there is a "end of production test" that simulates a stringent condition that the manufacturers can think off. In BMW, they strap the cars to a rolling road and simulate a range of driving conditions. For Jap cars, they drive the car off the line through a circuit before it hits the delivery yard and if it fails, they drive it back to a rectification area.
That's the reason why your owners manual stipulates the importance of running in. Of course iIf you intend to change cars within 2-3 years then just whack from showroom floor cos by the time the problems come up, they car will be sold... Just pity the next owner. So morale of the story, have a little mechanical sympathy and to a good even run-in and your engine will be quieter and torquier in city driving.
Cheers
The introduction of Shot peening was not to emhance the dimensions of manufactured products but rather to increase the durability of metals by removing microscopic "cracks" in metals that may lead to stress fractures under high loads such as turbo applications or >9000rpm speeds.
Nikasil was a new high silicon content steel that was harder than conventional materials that enabled cylinder liners to be manufactured thinner and boasted greater tolerance to thermal expansion. They were used together with molybedenum coated pistons to reduce friction. Honda was a great proponent of this and uses this technology in their type-R engines.
In MHO, no production manufacturer can run-in a car as it will consume too much fuel and man-hours just to run-in all the wearables (engine, transmission, driveline bearings, brakes) Usually there is a "end of production test" that simulates a stringent condition that the manufacturers can think off. In BMW, they strap the cars to a rolling road and simulate a range of driving conditions. For Jap cars, they drive the car off the line through a circuit before it hits the delivery yard and if it fails, they drive it back to a rectification area.
That's the reason why your owners manual stipulates the importance of running in. Of course iIf you intend to change cars within 2-3 years then just whack from showroom floor cos by the time the problems come up, they car will be sold... Just pity the next owner. So morale of the story, have a little mechanical sympathy and to a good even run-in and your engine will be quieter and torquier in city driving.
Cheers
centurion
Well-Known Member
Re: Engine run in
At BMW Munich, perhaps because of space limitations, in 2004, only 1 in 10 cars are track tested. Every car is strapped in rolling road with no simulation capability, and put to 130km/h for 30 seconds, checked for leaking fluids and then released, short drive to the car holding car park.
yendor;192725 said:
At BMW Munich, perhaps because of space limitations, in 2004, only 1 in 10 cars are track tested. Every car is strapped in rolling road with no simulation capability, and put to 130km/h for 30 seconds, checked for leaking fluids and then released, short drive to the car holding car park.
Re: Engine run in
Shot peening is not to get rid of cracks but to prevent them from starting by pre-compressing the surface layer of the material.
I don't recall Honda ever using Nicasil as was developed by the Germans, in their auto engines. It is popular in bike engines though. I believe they used a variant of it in some of their auto engines which utilized carbon and aluminium oxide, including the F20C which is the most stressed unit they have produced.
Bore coatings are not to minimize break in time but to keep ideal bore geometry and surface profile for a longer period of time. Nicasil (don't know about Honda FRM version), is very good at retaining oil. Excellent lubricity, and just doesn't wear out.
Pistons are not designed to touch the cylinder at all. It is supposed to ride on a film of oil going both ways. There is a significant amounf ot clearance between the piston and cylinder wall too. Contact does usually occur at breakover at top and bottom dead center from a lack of hydrodynamic lubrication. This is wear you most often see wear. Engine break in is mainly for the ring to cylinder wall surfaces, and some cams/lifters. . Production surfaces are rush finished. With more carefully prepared bores and rings, there is no run in to speak of. Race engines are put through their paces just minutes from first fire up unless there are components in other areas (like the valvetrain) that need breaking in - and that is rare, only occuring with some lower spec race engines.
You have control over geometry and finishes on components. It's just a matter of how much time and money is practical to put into it. Like others have mentioned, break in is also for numerous other areas of the car, and for the driver too.
Because component specification is never completely known with so many possible permutations, the manufacturers' recommendations (if any) on break in should be followed. They designed it, built it, know what's been done to it, so are in the best position to suggest a process.
Shot peening is not to get rid of cracks but to prevent them from starting by pre-compressing the surface layer of the material.
I don't recall Honda ever using Nicasil as was developed by the Germans, in their auto engines. It is popular in bike engines though. I believe they used a variant of it in some of their auto engines which utilized carbon and aluminium oxide, including the F20C which is the most stressed unit they have produced.
Bore coatings are not to minimize break in time but to keep ideal bore geometry and surface profile for a longer period of time. Nicasil (don't know about Honda FRM version), is very good at retaining oil. Excellent lubricity, and just doesn't wear out.
Pistons are not designed to touch the cylinder at all. It is supposed to ride on a film of oil going both ways. There is a significant amounf ot clearance between the piston and cylinder wall too. Contact does usually occur at breakover at top and bottom dead center from a lack of hydrodynamic lubrication. This is wear you most often see wear. Engine break in is mainly for the ring to cylinder wall surfaces, and some cams/lifters. . Production surfaces are rush finished. With more carefully prepared bores and rings, there is no run in to speak of. Race engines are put through their paces just minutes from first fire up unless there are components in other areas (like the valvetrain) that need breaking in - and that is rare, only occuring with some lower spec race engines.
You have control over geometry and finishes on components. It's just a matter of how much time and money is practical to put into it. Like others have mentioned, break in is also for numerous other areas of the car, and for the driver too.
Because component specification is never completely known with so many possible permutations, the manufacturers' recommendations (if any) on break in should be followed. They designed it, built it, know what's been done to it, so are in the best position to suggest a process.
centurion
Well-Known Member
Re: Engine run in
Well look at the bright side. 2 enthusiasts talking through their asses - caysman and yendor - and then the MAN comes in with the ground perspective, and even the ass talkers got a third right each with the MAN bringing home the final third.
You gotta love the forums!
Well look at the bright side. 2 enthusiasts talking through their asses - caysman and yendor - and then the MAN comes in with the ground perspective, and even the ass talkers got a third right each with the MAN bringing home the final third.
You gotta love the forums!
Re: Engine run in
Come on, don't say that. I know Rodney is a sincere person because we use to talk in real life quite a bit when I was just starting out in all of this and he was always helpful with no airs which is rare in Singapore.
I'm just providing another view based on what I've seen, read, heard from as wide and as high quality a range of sources I can find and keep. There is a chance my selection and cross-referencing methods are unsound, as well as understanding and memory faulty. If this is true or even somewhat true, then some of my facts, logic, network (and IMO a very earnest and good one), is part or entirely wrong. There are also errors in communication to factor.
The point of forums is to allow a logical and clean exchange so people can figure things out logically, no matter how long it might take. Often times it takes a while and still nothing can ever be completely proven, but that doesn't mean we shouldn't try. The earnestness and accuracy with which we present arguments speaks for how much or little we value truth or how seriously we take that which we claim as fact.
I for one would love to load a contrary and new data point after having understood its fresh and exceptional logic. There is such a range of engine type, applications, OEM and race build processes and materials, logic, test methods, that there might be something out there like this. Learning of an exception after trying your hardest to imagine one and failing, allows you to think up exceptions in other even remotely related areas and reduce the chance of getting caught by surprise. I know that isn't clear but is the best I can explain it right now. This is a benefit of looking at as wide a range of engines, vehicles, forms of racing, as possible - old and new, east and west, because they all are different, in varying degrees, from the next, yet something you learn from even one fringe form, often times applies, in at least some way, to the other hundred.
Come on, don't say that. I know Rodney is a sincere person because we use to talk in real life quite a bit when I was just starting out in all of this and he was always helpful with no airs which is rare in Singapore.
I'm just providing another view based on what I've seen, read, heard from as wide and as high quality a range of sources I can find and keep. There is a chance my selection and cross-referencing methods are unsound, as well as understanding and memory faulty. If this is true or even somewhat true, then some of my facts, logic, network (and IMO a very earnest and good one), is part or entirely wrong. There are also errors in communication to factor.
The point of forums is to allow a logical and clean exchange so people can figure things out logically, no matter how long it might take. Often times it takes a while and still nothing can ever be completely proven, but that doesn't mean we shouldn't try. The earnestness and accuracy with which we present arguments speaks for how much or little we value truth or how seriously we take that which we claim as fact.
I for one would love to load a contrary and new data point after having understood its fresh and exceptional logic. There is such a range of engine type, applications, OEM and race build processes and materials, logic, test methods, that there might be something out there like this. Learning of an exception after trying your hardest to imagine one and failing, allows you to think up exceptions in other even remotely related areas and reduce the chance of getting caught by surprise. I know that isn't clear but is the best I can explain it right now. This is a benefit of looking at as wide a range of engines, vehicles, forms of racing, as possible - old and new, east and west, because they all are different, in varying degrees, from the next, yet something you learn from even one fringe form, often times applies, in at least some way, to the other hundred.
