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What break in period did you follow?

  • Keep shifts under ~4500 RPM until 1200 miles.

    Votes: 35 81.4%
  • Keep shifts under ~4500 RPM until 500 miles.

    Votes: 2 4.7%
  • Break in period? The car is made to be DRIVEN. (No break in period)

    Votes: 1 2.3%
  • Other

    Votes: 5 11.6%
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Just passed you...
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Discussion Starter · #1 · (Edited)
This poll is for those who bought their car new...

What was your break in period?

1.) No full acceleration until ~1200 miles. (Shifts ~4500 RPM at most)
2.) No full acceleration until ~500 miles. (Shift ~4500 RPM at most)
3.) What's a break in period? (No break in period. Shifts at redline all the way home)
4.) Other

Look forward to reading everyone's choices and reasoning behind them. I will be getting my new car sometime next week and am unsure of what break in "theory" to follow.
 
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20,210 Posts
here's a great writeup from the org M3 board:

"I used to build engines, and while I don't claim to be the foremost expert I think that my opinion is at least a well informed one. It's not about short interval driving, Its about not being at a constant speed/ loading for extended periods.
New engine parts are all still getting to know each other and the most critical area is in the RINGS and their relationship to the cylinder walls. When they are new they still "leak" because they haven't settled into their long term relationship w/ the cylinder walls yet (in a microscopic sense of the word). The walls, for their part, are still "rough" and are being polished by the rings even as they wear micro-grooves into the rings themselves. Until this process is complete the compression rings will not seal completely.
This means that if you use a lot of throttle for a given rpm (hi manifold pressure) and the comression rings are asked to compress a LOT of air they will leak hot burning gasses past themselves and that's just a bad thing, causing premature wear. Later on they will handle the hi compression loads just fine, just not right now. That's why you shouldn't use full throttle b4 breakin=complete or EVER on an engine that isn't up to temp.
W/ regard to your original query ref long drives...if you are in city driving the engine drives the wheels AND during the frequent speed decreases the WHEELS DRIVE THE ENGINE. As you let off the gas w/ the car in gear to decelerate (engine braking) a strong vaccume is formed in the cylinders, as opposed to pressure. This pulls tiny amounts of oil UP past the also-not-yet-seated oil ring(s) and helps to lubricate the cylinder walls and the rings as they break each other in. THAT's why you need to vary the speed and avoid long idle periods on a new engine.
The reason for avoiding hi revs on a new engine is that while the parts are still new and "tight" hi piston speeds can actually pull a piston in half, leaving the rings and their part of the piston stuck in the top half of the cylinder while the rest of the piston and the rod beat the $$%^ out of everything else around them. It's a very ugly and heart breking thing to see.
SO FINALLY (sorry) my reccomendation is this. Spend the DAY driving around town, goofing off. Use light throttle and set a low limit to your revs (you shouldn't need more than 3500-4000 at most). NEVER use too hi a gear tho for your level of acceleration. Drive like a granny.Then Late that night, when the highway is relativley empty and you won't be pi$$ing everyone off, drive home at a constantly varying speed from, say, 45 to 60. Don't accelerate hard on the way up. Use a light foot. When you get to 60 lett off and let the engine drag you down to 45 again. Remember that the brakes and clutch also go thru break in periods of their own and highway miles aren't exercising them at all.
Don't be in a rush to romp on your new toy. Think of it as you would someone just starting to work out in the gym. If you do too much too soon you'll cause PERMANENT damage and never see it's full potential.

Good luck and congratulations. "
 
G

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I was pretty good at adhering to the break-in recommendations with my 330i. I had no problem keeping the revs down. It's just that I took a road trip during the first 1200 miles and it was very difficult to keep it under 100. I strayed a dozen or so times over the 700 mile roundtrip.

With my M3, I can only hope it's original owner was good about it. From the name (and the handwriting) inside the service manual's cover page it was an older German woman who was the car's original owner. IMO, that is the best possible demographic as Germans do respect cars.
 

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In Mod Heaven
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2,763 Posts
I adhered to the break-in guidelines. Only on an occasion or two did my revs go above the 4500 mark. I didn't go over 100 MPH at all. The car now has 4,100 miles after about 11 weeks and is finally running perfect.

Depending on your situation, some people go thru the break-in period relatively quickly. I think it took me 1 1/2 weeks to finish the break-in; while others take a full month or more.
 

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Registered
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atyclb quote:
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Originally posted by Closer
Good write up atyclb !!!!
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I just posted, I didn't write it, if anyone was confused about that.
My Bad :banghead: sorry
 

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My TARDIS is a BMW
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5,352 Posts
boring breakin period

Except for a very few times that I revved up very quickly and popped just over 4500 rpm, I stayed with the program.

Aside from believing that BMW knows best on this, my daily commute is in LA rush hour traffic, and you can't get going all that fast anyway:cry:.

In addition, I needed a lot of time to get used to the clutch in this baby. My old ride (86 Toyota Celica GTS) had gotten very sloppy :( after 15 years and I could practically clutch & shift in my sleep. Needless to say, but the BMW clutch was MUCH tighter and my feet needed to be retrained.

- howard
 

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Golf Fanatic
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26 Posts
I broke my baby in -- wait a sec, that sounds odd :rolleyes: -- I broke my car in at 1200 with revs no higher than 3500. I'm at 2900 now, watching every mile cause my baby (my car) is leased.

The furthest I've driven is San Diego (once) and Big Bear (once). Next furthest was Riverside ('bout 50 miles from where I live) to play a round of golf.... I suppose I'm a bit lucky cause everywhere I need to go is within a 10 mile radius :)

-Ed
 
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