Break In

[Meesha]

What is the proper way to break in the new car, especially for Lexus?

I am planning to buy a car from a dealer that is 100 miles away. I worry that if it's a good idea to drive the new car at a highway speed for that long.

I heard you don't want to stay at the same speed for a long time. Can I just vary between 60 and 70 mph? Should I get off highway a few times to let the car stop completely? Or, going that fast speed for that long is a no no?

I also read somewhere that most modern cars are broken in at the factory before assembly. Is this true? If so, we don't have to do the break in at all then?

I remember when I bought BMW, the salesman told me I don't have to do the break-in. The car got only 8 miles but it was ready to go. I wonder if this is the case for Lexus.

[GDixon]

First, ask the service manager at your dealership.

I was amazed that there is no break in period and no oil change after 500 miles like had been the case with other cars that have been bought new in the past. The service manager said that the moving engine parts were of such tolerance that no "break in" was needed. Just take it easy for the first few hundred miles. Keep it under 100 mph for a while.

There is no oil change until 5000 miles. I thought it was a misprint in the manual. The first oil change will be done at 3000 miles on my car just to avoid the worry and because I'm too old to learn new tricks.

The reason for the variable speed is so that the piston rings will not wear a pattern in the cylinder walls and then break when higher revs require them to go beyond, and impact, the lip in the cylinder wall that has been created. This would probably happen if you drove 1000 miles on cruise control so it is not likely in your case. The phenomenon was probably noticed on a factory test dyno that had the engine running at the same speed for months. 100 miles will not make a difference - just don't use the cruise control if you are worried. The minor variations when passing and when in traffic will be enough of a speed change.

New brakes are probably a bigger worry than the engine break in. They don't work as well until perfectly flat and aligned with the rotors. Several stops, especially from highway speeds will hurry the process.

[Bluey]

My understanding is that the materials and tolerances used in todays modern engine manufacture mean that the process of running a car in is virtually unnecessary. The other version I have heard is that engines actually run in better if run at very high revs, with load, for an initial period. I know my father was advised to this when the engine on his cessna plane was rebuilt, and is apparently done with race engines. Only problem with passenger cars is it's very hard to drive out of a dealer and leave it at WOT for the first ten minutes.

[DArustik]

All I would do is not go over 4500 RPMs at 75 MPH for the first maybe 500 miles. Also, just be aware of the brakes and how they are not all that good yet. Don't worry about all this engine stuff by putting the car in cruise.

[dcfish]

All I would do is not go over 4500 RPMs at 75 MPH for the first maybe 500 miles. Also, just be aware of the brakes and how they are not all that good yet. Don't worry about all this engine stuff by putting the car in cruise.

There is no break-in period. These cars are built to go top end from the factory. The best technology in the world goes into our cars. Back in the day when an engine was rebuilt , Either it went full throttle for a race or it didn't. Then it was fixed and the same procedure was in place, Either it ran or it didn't. Our cars have no problem running, They are overbuilt.

[CrunchySkippy]

The reason for the variable speed is so that the piston rings will not wear a pattern in the cylinder walls and then break when higher revs require them to go beyond, and impact, the lip in the cylinder wall that has been created.

GDixon - I believe you are right, but for the wrong reason. A piston goes through the same stroke, regardless of RPM. (eg: it doesn't "go beyond" when given more throttle.) :)

[dcfish]

The reason for the variable speed is so that the piston rings will not wear a pattern in the cylinder walls and then break when higher revs require them to go beyond, and impact, the lip in the cylinder wall that has been created.

GDixon - I believe you are right, but for the wrong reason. A piston goes through the same stroke, regardless of RPM. (eg: it doesn't "go beyond" when given more throttle.) :)

Agreed 100%

[GDixon]

The reason for the variable speed is so that the piston rings will not wear a pattern in the cylinder walls and then break when higher revs require them to go beyond, and impact, the lip in the cylinder wall that has been created.

GDixon - I believe you are right, but for the wrong reason. A piston goes through the same stroke, regardless of RPM. (eg: it doesn't "go beyond" when given more throttle.) :)

OK, final rebuttal. <_<

The pistons under normal temperatures do indeed go through the same stroke unless the rod bearings are loose or worn. The pistons do not touch the cylinder wall but the rings do instead. My point, as was originally stated, involved the piston rings which have a built-in tolerance so that they will move in the lands regardless of the piston temperature. Metal does expand when heated as you probably know. That results in a bit of wobble which is even a bit more evident when the engine is cold since the design is for them to expand when warm. (The rings get larger and the land gets smaller since the walls of the piston heats up first along with the top.) It is also a fact that the connecting rods slightly lengthen when the engine runs hotter causing the stroke to be longer by enough to cause the rings to hit a pre-existing worn lip at the top of the stroke. That could cause ring damage in extreme cases.

Apologies accepted in advance.

BTW, if there is a better explanation, rather than sniping, let 'er rip. :)

[dcfish]

The reason for the variable speed is so that the piston rings will not wear a pattern in the cylinder walls and then break when higher revs require them to go beyond, and impact, the lip in the cylinder wall that has been created.

GDixon - I believe you are right, but for the wrong reason. A piston goes through the same stroke, regardless of RPM. (eg: it doesn't "go beyond" when given more throttle.) :)

OK, final rebuttal. <_<

The pistons under normal temperatures do indeed go through the same stroke unless the rod bearings are loose or worn. The pistons do not touch the cylinder wall but the rings do instead. My point, as was originally stated, involved the piston rings which have a built-in tolerance so that they will move in the lands regardless of the piston temperature. Metal does expand when heated as you probably know. That results in a bit of wobble which is even a bit more evident when the engine is cold since the design is for them to expand when warm. (The rings get larger and the land gets smaller since the walls of the piston heats up first along with the top.) It is also a fact that the connecting rods slightly lengthen when the engine runs hotter causing the stroke to be longer by enough to cause the rings to hit a pre-existing worn lip at the top of the stroke. That could cause ring damage in extreme cases.

Apologies accepted in advance.

BTW, if there is a better explanation, rather than sniping, let 'er rip. :)

You have to take into consideration that the materials used in the engine components have been taken into consideration during design phase. Expansion/Contraction #'s are well within tolerances for longevity of the toy/lex engines. Buy the car, Drive it any way you want, Maintain it within your driving habits.

[bartkat]

Follow the instuctions in your owners manual as you can't go wrong with that. There is really no need for debate. Avoid sudden starts and stops because the tires and brakes need to be seated in. If you're only going 100 miles, just don't drive at the same speed for the whole distance. Traffic will help you take care of that. I drove 700 miles when I had just 200 miles on my car. I would drive 10 miles or so at 65, then 10 at 70, then 60, etc. It's really only important to just vary the speed somewhat instead of running at any constant speed. You should do this for the first 600-700 miles.

All of the above posts are opinions based on science, mechanics, and some voodoo. Just do what the manufacturer recommends, which is what I have posted above.

[dcfish]

Follow the instuctions in your owners manual as you can't go wrong with that. There is really no need for debate. Avoid sudden starts and stops because the tires and brakes need to be seated in. If you're only going 100 miles, just don't drive at the same speed for the whole distance. Traffic will help you take care of that. I drove 700 miles when I had just 200 miles on my car. I would drive 10 miles or so at 65, then 10 at 70, then 60, etc. It's really only important to just vary the speed somewhat instead of running at any constant speed. You should do this for the first 600-700 miles.

All of the above posts are opinions based on science, mechanics, and some voodoo. Just do what the manufacturer recommends, which is what I have posted above.

Please explain what you mean by "VOODOO" TIA

[bartkat]

I think you know what I mean. :D

[dcfish]

pm me

[CrunchySkippy]

The topic of this thread is about breaking in a new engine. It is not about dreaming up a catastrophic engine failure to scare new Lexus owners.

I'm still laughing about the reference of high rev's requiring the piston to go further. Oh, I know...you mean when its hot, because you told us that heat causes metal to expand...and engines don't ever get hot (as in the operating temperature of an internal combustion engine).

But again, somewhere in your response I think you have the right idea. But now I think you don't have any idea why.

The fact is that you WANT to increase ring pressure against the cylinder walls so that the piston ring DOES seat properly. This is what acceleration and decceleration accomplishes. And driving at a constant speed does not.

Thank you for accepting my apology. :whistles:

[bartkat]

It's in the book:

Breaking in your new Lexus

To extend the life of the vehicle, the following precautions are recommended to

observe:

For the first 186 miles (300 km):

Avoid sudden stops.

For the first 621 miles (1000 km):

• Do not drive at extremely high speeds.

• Avoid sudden acceleration.

• Do not drive continuously in the low gears.

• Do not drive at a constant speed for extended periods.

http://us.lexusownersclub.com/forums/index...ost&id=3754

[Meesha]

Thank you for replying to my questions!!

I got an idea now.

Bottom line is I will follow the manual.

But... one last question...

"Do not drive at a constant speed for extended periods."

What is the "extended periods"?? That could mean 50 miles? or 300 miles?

I wish Lexus would be a little more specific about this ;)

[bartkat]

Thank you for replying to my questions!!

I got an idea now.

Bottom line is I will follow the manual.

But... one last question...

"Do not drive at a constant speed for extended periods."

What is the "extended periods"?? That could mean 50 miles? or 300 miles?

I wish Lexus would be a little more specific about this ;)

I thought that was already covered in one or more posts. The thing is you just don't want to drive 20 miles on cruise control. Every few miles speed up a little and slow down a little. That sounds vague, but the main thing is not to go long ways at constant speed.

When you get to 622 miles then you can drive however you want. LOL