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08-19-2009 11:38 AM #1
Engine break-in procedures at factory
Hi All. Just finished a rebuild on my '85 M30 and have a question about break-in procedure (I know it is a controversial subject). There are web sites that insist that running the engine fairly hard right off the bat is necessary for ring seating, and others that advocate an easier approach. I replaced the rings (but not pistons), main and cam bearings, honed the cylinders and cam. I have so far done an initial 15 minute start and idle, and everything seems OK so am about to take it out for the first drive. I'm a believer in trusting the engineers that design and build things (particularly BMW engineers and with an engine that has been around for 30 years), so does anybody know what BMW recommends for break-in - not just what they say in the owner's manual but what they do themselves at the factory on the initial start-up and first first running/driving? I presume that they don't take spend the time to take each car out individually to run them around the track, varying the engine RPM and load, cooling it down between run-ups, etc (except maybe with M's and top end vehicles). Do they run them up on dynos? Drive them from the factory floor to the freighter? Surely they must be idled and lugged and not properly treated during the critical break-in period by the guys who move them around between the factory and the final buyer, and yet most seem to end up running well for years! And this is with all brand-new parts! Anybody know? Thanks.
08-19-2009 12:53 PM #2
09-14-2009 02:05 PM #3
- San Pedro, CA, United StatesMember No: 52098
- Join Date
- Oct 2002
- Rep Power
Reposted from E23 section...from the owner's
The first 1,200 miles, do not exceed 2/3 of the road speed in each gear.
Or: 20 mph in 1st, 40 mph in second, 60 mph in 3rd, and about 90 mph top speed during break in. Do not use wide open throttle during break in, nor if an auto tranny, do not use the throttle kick down to shift.
Do not run more the 4,000 rpms, in other words.
From the Factory Repair manual...
Do a first oil change at 600 miles and a second oil change at 1,200 miles. Don't forget, if you have an oil cooler to run to full running temp to flush out the oil cooler circuit.
When I had an E28 535i, I ran all the way to redline with an engine I took to over 303,000 miles before junking (though not from new). These cars are made to run at max performance for a few hours at a time.
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