Here is my opinion. Piston Rings are held, for the most part, against the cylinder walls by the cylinder pressure created, in part, by the ignition of the A/F mixture, and this cylinder pressure is at it's highest (thus the rings are being pushed against the hone texture the hardest) during accelerating with WOT operation. The hone texture on the cylinder walls, during it's very early life, is at it's sharpest texture therefore promoting (at the highest level during the Motors life) the complete sealing (lapping-in) of the rings with the cylinder walls. As the hone texture is smoothed, by this breaking-in process, the ability of the hone texture to seal with the rings is diminished dramatically. So, aggressive operation of the 55K motor from the beginning will ultimately result in a motor that seals better at the rings and will put out more Hp because of this.

Now, this does not mean that you can run the 55K motor at WOT during the break-in period for extended periods of time (more than 45 sec.) before letting off. If you do, excessive heat will be introduced into the motor due to the relatively high level of friction at the ring to cylinder wall junction. The idea is to make a WOT run for lets say 15 sec. (assuming enough road is available) then cruise for 2 to 3 min. to cool the motor down, and then do another WOT run and a cool down period, and so on. This type of driving behavior is difficult in most area so just general aggressive driving accomplishes this break-in method, because you have to slow down quickly anyway because there is not enough road ahead and traffic gives time for the motor to cool down until the next opportunity comes along for another WOT blast.

Weather you subscribe to this method of break-in or not the 55K motor will run fine in the end, however the 55K motor broken in with this method will run the best.

Also, I change the oil & filter four times during the first 1,000 miles, the first at 100 miles, the second at 200 miles, the third at 600 miles, and the fourth at 1,000 miles. The reason for the filter change is to make sure that, as much as possible, the suspended metallic residue from the break-in process is removed from the motor's oil system and a new filter ensures that the best chance of this happening will occur.

Anyway, this is far more fun than keeping it under some prescribed RPM for a WHOLE 1,000 miles. - Bob

 

I completely agree!! Breaking an engine in hard gets most power from the engine.

 

My CDI was broken in on the dyno when I added the Renntech tuning.. I had a total of 200 miles on the engine with I did it... but we did at least 10 runs to 4600rpm (redline is 4700).

I also changed my oil / filter at 1000, then 2000... and now I'll do to it at 6500, and 13000 etc...

 

It's not just the engine that is effected during break-in; the transmission, diffy and other drive train components are too.

 

true.. I wonder if they're as susceptible though? good point though.

 

I would say it's a fine line. There is post after post of E55 guys who did not beat the tar outta their cars, but did not baby them like they were told, and the cars seem to just produce more power.

Gid-e-up is a firm believer of "break um in like you drive um" and he posted the highest stock on an E55 to date.....517.

Mine, according to the guy I bought it from, was pampered like a baby's bottom.....I posted 496 WITH the speedtuningusa ECU mod on....

Same style motor....same style car....without ECU, mine would be off something like almost 40hp.

Cory at Kleemann told me it mostly is the break in of the ECU....when you are aggresive, the ECU learns your pattern and adjusts accordingly......he said if you wanna try it, disconnect your battery terminals for an hour....then connect and "drive it like you stole it" for 400 miles.....it will be a whole new feeling car.

Now long term effects of that on a new car......jury is still out.

 

I think traction limitations are the safty valve for the driveline systems during the break-in period. Also the 5 Speed Trans is rated to 700+ lb. ft. of torque, so it is being under utilized as it is. - Bob

BTW - RJC that new M3 you have on order caught my eye also. Where can I find more info. on it?

 

No matter, I'd still take it easy...

The E90 forums are the best place to get info. on this sweet little ride.

 

I also changed my oil / filter at 1000, then 2000... and now I'll do to it at 6500, and 13000 etc...[/QUOTE]


When you guys are changing your oil that often are you still using full synthetic?

 

When you guys are changing your oil that often are you still using full synthetic?[/QUOTE]

In my case it's Mobil 1 Delvac 5W-40 FULL SYNTH. Best Diesel oil around IMHO. Oil is cheap, a new CDI engine is roughly $14,000 (I checked). I would venture an AMG is about twice that!

 

There was a great article in May 94 Issue of Circle track & racing Technology Mag. Done by the late Great , Smokey Yunick. Called SOFT HONING.

There was another ( really old) one done by Steve Rands . He worked for Brush Research Manufacturing Co. of Los Angeles . Article The Last Lap. It is about the use of Flex Hones

I know you guys are going to Laugh, There is a big problem with Asia build 4 stroke outboards. Rings don't seat up. they come back with gas in the oil. I tell them to run it like you stole it. They have got overcooling at low speed. They just have not figured out the duty cycle of this type usage yet.