question on break-in procedure - United Bimmer Community

**nightdevils** · 02-22-2006, 10:04 PM

So the manual says, upto 1200 miles, drive at varying speeds, and not to exceed 4500 rpm. Does anyone know the exact reason for limiting the RPMS? My bro's rx8 doesn't have rpm limitation for break-in procedures, and wondering why the difference.

**nightdevils** · 02-22-2006, 10:05 PM

At the same time, aeroplane engines recommend going full throttle (for the piston kind) for break-in.

**BMWLotAttendant** · 02-22-2006, 10:11 PM

The new M5 has a break in procedure too....no going faster than 130mph for the first 1200-1500 miles.

I think it is to slowly make sure things are running right...and break stuff in.

nick_318is · 02-22-2006, 10:23 PM

Sometimes nice things need to be broken in.

witeshark · 02-22-2006, 10:30 PM

The variation of engine speed is to keep the engine from forming rev habits that would happen if it spends too much time at any one speed. With planes that run the exact same revs for long periods, this is not an issue.

**nightdevils** · 02-22-2006, 10:40 PM

Quote:

Originally Posted by witeshark

The variation of engine speed is to keep the engine from forming rev habits that would happen if it spends too much time at any one speed. With planes that run the exact same revs for long periods, this is not an issue.

True, how about the limitation of the rev to be less than 4500 rpm. Why that specific RPM. If they wanted to allow varying speeds, shouldn't they also also for variable RPMs without limitation?

witeshark · 02-22-2006, 10:45 PM

Simply because the speeds above 4500 are too high for a new engine.

**komodo** · 02-22-2006, 10:46 PM

All the parts are smooth and new, I'm guessing it's to wear them down a bit in the correct patterns to make them work together smoother.

(completely a guess though, no factual backing)

Storamin · 02-22-2006, 11:04 PM

http://www.mototuneusa.com/break_in_secrets.htm

End of story, nuff said

YMMV... literally.

**nightdevils** · 02-22-2006, 11:17 PM

Storamin, thats exactly what I was looking for

My brother mentioned something similar but I wasn't sure. Thanks a million!

**c1apton** · 02-22-2006, 11:56 PM

That "break in procedure" is so the piston rings seat and develope a slow wear pattern. Also so the internal bearings all seat. (amongst other things)

**nightdevils** · 02-23-2006, 12:15 AM

Here's the million dollar question (the whole para

): so what if my car wasnt properly "broken" in to? I am saying this b/c this is a 2001 e39 with 26k miles. The driver more than likely didn't drive the car that often, and I wouldnt be surprised if he didnt follow the "varying speeds" seriously. My first order of business after I get the car back from the body shop is to take the car in to the dealership and get the gaskets changed-> oil leak (bmw tech said that before we got rear-ended). I will also take a sample of the engine oil and send it in for analysis. But I am wondering if there's anything that could be done to fix bad break-in scenarios.

**c1apton** · 02-23-2006, 12:19 AM

The biggest concern if you suspect bad break in, is if you have an oil burning problem. Gaskets leaking are a syptom of doing alot of sitting, the gaskets dried out. I'ld only be concerned if you have engine bearing noise or oil burning. Have your "tech" do a compression test when you have it in.

**xsperf** · 02-23-2006, 12:21 AM

yeah, and a bad break in wont show anywhere near 26K.. much higher up it may show

**nightdevils** · 02-23-2006, 12:38 AM

I see, will tell the tech to do the compression test. BTW any other things I should check for .. for a car that had been sitting for a long time?