Breaking In New Engines and Engine Oils

By Scott Rogus

First, let’s cover the basics of breaking in a new engine.
The engine break-in issue is the subject of much controversy as everyone seems to have their opinion on when an engine is considered fully broken in.

The information we provide is based on the results of engineering studies...
as well as many years of experience and teardown analysis on test vehicles. The differences between a vehicle that was properly and fully broken in and one that was not can often be hard to detect, yet there are tell-tale signs of this but they are not easily detected except in all but the most extreme situations. The subject of what occurs during the break-in process can easily be the subject of a 100 page report therefore what we cover in this web site page is only the essential points you need to know.

Breaking in an engine is a process of properly wearing-in...
the pistons/cylinders/rings, bearings, valves, camshaft, lifters, rockers, etc... In addition, part of the breaking in process is not only wearing-in and seating the internal engine components but also stress relieving the components as well. Crankshafts, connecting rods, pistons, blocks etc... have many stresses due to the casting or forging process, machining and welding process. We have viewed and measured these stresses, called fringes, using what is called lazer holography. These stresses are properly reduced/eliminated by costly and time consuming heat aging as well as shot peening and or high frequency vibration on a very specialized bedplate for an extended period of time. For production applications this is cost and time prohibitive. Therefore, the next best thing is exposing your engine to multiple heating and cooling cycles under various load and RPM's, which is described in the following paragraph. The heating and cooling break in process continues over a period of time and does not need to be run on petroleum oil.

Breaking in a new engine...
is the one area that petroleum oil is better for than synthetics. You see, petroleum oil has a very low film strength which is ideal for breaking in a new engine. That is why we recommend you run the factory installed petroleum oil for about the first 500 miles.

Further heat cycling break-in will continue during the multiple heating and cooling cycles from driving your vehicle under varying RPM and engine load conditions and then shutting it down for a long period of time to let it cool completely. The multiple heating and cooling cycles are a extremely important factor in properly breaking in a new engine and are often an overlooked factor in the total break-in process. These heating and cooling cycles achieve what is called stress relieving. Back in the "old days" of engine manufacturing, after casting and before an engine block was machined, it would be set outside for several months to age, during which stress relieving occurred naturally, then the block was machined, which helped to produce a better engine than one that was machined immediately after casting.

By changing the factory installed oil and filter after the first 500 miles...
you will also be removing the initial wear-in particulates present in the oil and filter. The reason for this is that during initial wear-in there is very high particulate contamination in the oil. These particulates consist mainly of microscopic particles of aluminum, bronze, copper, lead and iron, plus soot particles and other by-products of combustion in your oil. Your filter cannot filter out all these small particulates as many are sub-micron size and too small for the filter to trap, BUT they are also small enough to fit between your bearing and other internal clearances and cause wear. That is why we recommend to that in order to properly break-in a new engine, regardless of what your new car salesman or dealership personnel tell you, is to perform the first oil and filter change at 500 miles.

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