[HoosBMW]

Hey,

I know a lot of people talk about breaking in the engine....

What i want to know is why....and what does it affect if you do or don't.

Not trying to be a smart a**...just wondering...I have heard so many things...i just want to know exactly what is effected...thanks a lot guys..

by the way everyone in this forum is freakin' awesome....you guys are so helpful.... :rocks:

[Meatnog]

Depends on how long you're planning on keeping the car. I keep hearing from BMW and dealers that there is no official breakin. But BMW only considers the 'lifespan' of the car to be 100K miles.

So, basically, from what we've gathered is that up to 100K miles, there's really no difference. Over that, you may get some extra life out of the engine.

[SteveMD]

Most manufacturers don't require this any more. It used to be a ritual for every new car. Since BMW puts it in the user manual, I will be doing it.

One thing I always do is change the oil and filter at 500 miles. Just in case there's a metal shaving or two in there.

[shragon]

i'm following it, since bmw put it in the manual. but when i asked my sales guy (a long time bmw sales person), he said there really isn't much of a break-in period any more for new bmw's. he just said, try to be some what gentle with it for the first 1000 miles.

[06330i]

yea u arent supposed to rev the engine over soo many rpm's, i cant remeber exctly what it is, the engine runs real rich,when it first breaks in

[vladinecko]

think of it as buying a pair of new shoes. you gotta walk careful in them because if you start running a marathon right off the bat, they will hurt your feet really bad. you gotta wear them down a little, make 'em loose, stretched and adjusted to be able comfortably walk in them.

same with the engine, there are some moving internal parts that are rubbing against other parts so you gotta take it easy at the beginning to give those parts time to adjust and smooth out. if you push it too hard during break-in period, you risk making things way too loose.

i think it's also some kind extended testing period where they're basically saying, if nothing major happens to the engine/breaks etc. in the first 1200 miles, it is safe to assume that there are no significant manufacturer defects in the car and therefore you can feel free to push it to the limits.

[sdorn]

The manual says to vary engine speed for the first 1,200 miles. Also, keep the revs below 4500 and the speed under 100mph.

I have also read some interesting articles that seem to indicate that driving a car delicately during the break-in period leads to lower performance, and that driving the car extremely hard during breakin is actually more conducive to the car having better performance.

I had a custom built motor put in my Mustang, and the engine builder actually broke the engine in on the dyno doing complete runs to the redline. He started off pulling up to lower rpms, then worked his way up to doing several redline runs. That car runs like a champ, although I have only put another 12,000 miles on it since the new engine went in.

[Zartok]

Breaking in an engine too gently can affect performance. The ECU is learning how the engine is being used so for better throttle response it's worth varying speed regularly rather than cruising during the break in period.

[xenocide]

Here is the best information I have found so far on breaking in an engine. Read the long post towards the bottom; especially the technical section:

http://member.rivernet.com.au/btaylo...kInPeriod.html

From the article:

The Theory. The primary goals of engine break-in are: 1) achieving a
good seal between the piston rings and cylinder walls, and 2) allowing
the engine to operate correctly throughout its RPM range. The major
enemy during the break-in period is localized heat buildup, mainly in
bearing surfaces (most notably the crankshaft bearings).

It's a good read!

[donger274]

also got to break in your clutch for you 6mt out there