Yeah DDCrew...that is the part that most of the "performance" guys said is hogwash. They said driving moderately will not seat the rings well enough and you will end up leaving horsepower on the table.

Here is a quote from someone on the C5 forums:

"38 years of building race & performance engines, performance part R&D, and years of owning/running/crewing race teams with numerous Divisional. National, and World Championships in both NHRA & IHRA in several classes.

Immediatley drain the syn oil and put a GOOD dino oil in with a premium oil filter.

Do not use cruise control as mentioned above, you want to vary the RPM's as much as possible. The bearings/journals dont need a break-in, but proper ring seating is critical and oil consumption is the result of them not sealing properly.

Drive the car hard (safely!!!) and dont worry about the 4k limit, just stay off the rev limiter. (most engines we build are broken in/rings seated by the time were done with the dyno pulls during tuning). The window to seat rings is very short, 500-1000 miles and the syn oil is too protective to allow proper seating. The cylinder walls will form a hard glaze after 500 or so miles so it the rings are not properly seated, they may never be.

After driving hard for 500-1000 miles, get the dino oil out and switch to a good full syn, premium filter, and your good to go.

This is of course IMHO as it is all contrary to the owners manual (which is to prevent a warranty claim early on, and NOT to properly break a motor in).

NO quick deceleration from high RPM's in gear, just let it baby on decel, but the motor needs to see many rpm's and NOT babied.

Oh, install a good functioning oil separating catchcan right away BEFORE the ingestion causes gunk/carbon buildup issues.
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SlvrShrk - Keep in mind this engine was not built at some speed shop where they dyno tune it. It was built in Mexico and it has a plastic oil pan (Nylon, glass reinforced). Also, the user's manual doesn't state to use cruise control; the way I understand it is that "while cruising", vary the speed within the speed limits and brief full-throttle acceleration within the limits of local traffic laws contributes to a good break-in.
Anyhow, many of us will have different opinions on this based on experience and input from various mechanics. At least when following the user's manual, when something does break, there will be no reason for Dodge to deny a claim.

 

True...good points...

 

I am by no means an expert automobile mechanic, but I have been operating, maintaining, rebuilding, and breaking-in marine diesel engines for the past 8 years at my day job. Our standard practice for breaking in a freshly rebuilt engine usually has 2 major parts to it; which affect 2 different parts of the engine. First, we have several runs of the engine under "no-load", where we incrementally increase the RPM and length of each run, but all with no load on the engine. We start with a 1 min. Run at idle, and progressively work our way up from Idle in 10% increments to 75% above idle, and gradually increase length of time with each run as well. During the shutdown period between runs, we take oil samples to test for fuel dilution (fuel leaks into the oil which thin it out), oil thickening(caused by coolant leaks into the oil), and also we pull open all the crankcase inspection covers and check the temperatures of all main and rod bearings to ensure that they are all breaking in nicely and don't have a spun bearing or bad bearing(sometimes due to manufacturing defects). So for the entire "no-load" period, we are concerned solely with the bearings getting a good proper break-in and identifying any issues with the bearings as soon as possible. We don't really care about the rings yet, as they do not start to break in and seat until the loaded runs, which will be next. The reason the rings don't seat or break in without a load is because you need a high firing pressure in the combustion chamber to force the rings to open up and begin making contact with the cylinder walls with enough force to wear the surface of the rings and cylinder bores. Kind of like trying to wax your car with little to no pressure on the rag you are using to wipe off the wax once it has dried. At light or no load, you have less fuel being delivered to the cylinders, and the less fuel, the less the firing pressure in your cylinder, and the less pressure in your cylinder, the less the rings will be forced against the cylinder walls and the less they will wear against the cylinder. So for the next phase or our break in process, we incrementally add load to the engine, and also increase the length of time of each run, and we stop and inspect the rings between each run(we mainly use 2 strokes with intake ports in the cylinder liners, so we can actually see the impression rings through the ports and watch the wear on the rings increase as try start to seat). We can actually see a noticeable decrease in the amount of oil that leaks past the rings into the airbox as tr loaded break-in runs progress with more load and longer durations.

So, anyways, based on all of that, I am under the impression that I would take it easy for for the first maybe 50-100 miles to allow the bearings a chance to wear in without much strain or load on them, and ensure you let it idle long enough to reach operating temp before driving it do your oil can achieve its designated viscosity. Then, for the rings to break in, I would gradually run it harder and harder, taking care to keep your throttle position/rpm constantly changing; don't keep it at same speed for an extended period such as cruising on the highway at same speed or use cruise control. This is also a great opportunity to learn the fun of the autostick. Then, the more miles you put on it, start doing more and more agressive "pulls" or runs, giving it some healthy accelerations to put a bigger load on the engine. Like I said above, the more load, the more fuel, an the higher your firing pressures, which is what you want while your trying to get the rings to break in. Anyways, that's my .02 cents.

Like I said, I'm no auto mechanic, I'm just going off of my own knowledge and experience with what I work on, but I feel the principles are similar.

 

Thanx snype! Great info. Very educating for a very non-mechanic person like me!

 

Sounds good and agrees with all the popular engine building and hot rodding magazines on engine break in. I know I have over 400. (wifee hates them) Anyways the three most important things according to the mags are.
1. Be easy on it for a couple hundred miles varying your speed and limiting short trips for proper oil temp for the bearings.
2. Drive it like you stole it to seat the rings and valves, staying off the limiter. At 500 miles accelerate (WOT) between 45-75mph using engine braking to slow you down a few times.
3. Change your oil and filter the first 2,000 miles or less.


Also the magazines all seem to use the factory manuals suggestion on transmission break in. Full throttle downshifts at varying speeds after the first couple hundred miles.