I thought I would start a new thread that was focused on Motor & LSD Break-In so that the subject matter was not buried in some off topic thread. Below are some of my thoughts on the subject from the other off topic threads.

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"IMO Break it in hard, however always give it a couple of minutes, at least, between WOT sessions (10 to 15 second long WOT Sessions) for cooling down at normal diving levels. The first 300 to 400 miles is when you have the best opportunity to best seat the piston rings. From there the seating process diminishes because the original honing pattern in the cylinder walls has lost most of it's original aggressive texture, thus reducing it's lapping-in capabilities.

Why does WOT operation produce a better Piston Ring seal? When the Motor is at WOT cylinder pressure is at it's highest levels and because of Piston Ring design and Piston Ring-Land design the Rings are being pressed into the cylinder wall at the highest levels during WOT operation. Therefore, being lapped into the cylinder walls aggressively and conforming to the cylinder walls better producing a higher quality seal and thus reducing the leak down of combustion gases past the rings. When this occurs there is more combustion pressure on top of the piston and therefore more work is performed by each combustion cycle.

Now, I also feel that changing the oil filter and oil (Mobil 1 0W-40 Oil) at around 350 miles, 700 miles and again for the third time at 1,000 miles is important to keep the metallic lapping-In residue produced from building up in the oil filter and Motor. As evidence of this Lapping-In Residue, you will see when the oil filter is removed at 350 miles that it is medium gray in color which is a significant color change from the original white color of the filter.

So, as you can see, when you break your CLS55 in hard there are added responsibilities that go along with it to help with maximum protection of the Motor during the process. Keep in mind, it's not an abusive process but an attentive and respectful process.

030 LSD cars I believe should have the OEM recommended CASTROL SAF-XJ 75W-140 Fully Synthetic Gear Oil changed at 600 Miles, 1200 miles, and a third time at 1,800 miles to reduce the contamination in the gear oil during the LSD break-in process, when using the "Hard Break-in" method for the Motor. The LSD gear oil resides in an unfiltered environment and will benefit as the Motor does from more frequent gear oil changes. BTW, it took some searching to find this MB specified Gear Oil in my area. - Bob"

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"The Castrol Synthetic SAF-XJ 75W-140 Gear Oil is the recommended MB OEM Gear Oil for the CLS55-030 cars with LSD.

The intervals are arbitrary on my part and were spaced evenly over the MB recommended break-in period for the LSD. The theory being that removing the contaminated oil three times during the break-in period, instead of once, would reduce the abrasive contaminates in the gear oil that can eventually overcome the lubrication ability of the gear oil. When this happens not only do the gears not seat properly but the bearings also can wear abnormally.

Also, the higher pressures developed in the LSD, while breaking it in this way, will introduce more aggressive contaminates into the gear oil, raising the risk of LSD failure. So changing the gear oil more often than recommended will remove most of these more aggressive contaminates, helping the LSD to survive this type of break-in.

Now, this is all base on the conclusion that the type of Motor break-in is more important than the type of LSD break-in. At best it is a roll of the Dice with some effort taken to keep the Gear Oil cleaner than it would have been during the MB OEM recommended break-in method.

As far as what interval to choose, in theory, the more changes the better. However, the law of diminishing returns will come into affect at some point. I chose three changes. - Bob"

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All you "Motor Heads" Please participate in this thread for the benefit of all the Forum Members. Thank you in advance. - Bob

 

I thought I read somewhere that these engines we have in our AMG cars have already been run at WOT in the factory after they are built. Wouldn't the rings already be sealed after they do this testing of the motor?

I don't really know much about engines so I'm just taking a guess here.

 

Stiggs - MB actually runs the motor without running the fuel and ignition systems. It is done on a machine that turns the motor over while checking cylinder pressure, oil pressure, and I am sure some other things. So the motor is not actually fired up until it is driven off the assembly line. - Bob

 

You know, I have heard this debate so many times in the last year or so, the Drive-it-Like-You-Stole-it-to-Fully-Seat-the-Pistons Break-in Method....

I am buying a bunch of new AMG vehicles this year - a bunch - so I am going to ask two of my tuner/raceshop/motorhead and engineer professionals, and I am going to ask the techs at AMG and the other car factories that I should be visiting in Europe here in a few weeks...and then I will weigh-in with their opinions. How's that sound?

 

Sounds good to me. Just like a research paper for a science class. Only fun this time.

 

I just came back from my dealer this afternoon to get an update on my car (E55), which just entered production as of 2/14/06!!!! Can't wait to get my hands on that baby.

But I also asked him about the break-in procedures and what do they tell their customers who buy the AMG cars (this is a factory dealership, not a franchised). He said "we tell our customer to drive their AMG cars the way they would normally drive, there is no need to baby the car. The engine has been bench tested fully at the factory, so the only recommendation we have is to have new owners change their oil 2-3 times before the first recommended schedule, so the engine debris can be cleaned out. Other than that, enjoy the car."

The guy owns a CLK55 himself (not a company loaner), and he said he drove his car the same way right from the beginning, and it still feels just as tight and powerful as when he first got it years ago. So he told me there is no need to baby the car. He wouldn't recommend WOT all the time right from the beginning, but he said we can definitely have fun with it right off the bat.

Anyway, just passing along what I heard.

 

TTT - - Bob

 

I have just changed the Gear Oil in the LSD of my CLS55- 030 at 780 Miles, and I am very glad I did. The oil was a dark gray, due to all the contaminants that were produced during the initial miles of the break-in period. I plan on changing it another time, around 1,100 miles, and again at 1,875 miles as recommended by MB.

I have driven the car relatively hard so far, although not as hard as I would have liked to because of the general traffic conditions I have been driving in. So, along with breaking the motor in hard, I highly recommend changing the LSD gear oil at least three times or more to keep most of the contaminates produced during the break-in period down to a minimum and from recalculating thru the gears and bearings.

Quite frankly I do not understand why MB recommends changing the gear oil at 1,875 miles, given the condition of the gear oil when I changed it in my CLS55-030 at 780 miles.

Also, MB has only one gear oil that they recommend (Castrol 75W-140 SAF-XJ), which is not sold in the US as a retail product. It can only be purchased as a commercial product in 16 Gallon Drums. I think MB should increase the number of Gear Oils that are included on the recommended Gear Oil list to at least three and also include some that are available on a retail basis. - Bob

 

As a wrap up of this post, when I changed the LSD Oil the second and third times it was substantialy cleaner than the first time. The car is not driven much, it has about 2800 miles on it and at this point there are no unusual noises coming from the Rear Diff. - Bob

 

Still on my list of discussions to have with the folks in Affalterbach..whenever I finally get over there(!) ....

I am thankful that you have stayed on this, though.