When OEM's measure profits on pennies or less per item, spending 1/2 hour on a break in dyno just doesn’t happen (on the mass production automotive side). One of the primary reasons for a break in is to allow friction items (mostly the rings, piston skirt, and cylinders and the cam surfaces) to mate. With today’s precision machining and rolling friction surfaces (cam followers) there is little need for a strict break in procedure. A simple light load or fast idle the first minute or so followed by moderate driving the first hundred miles is generally sufficient.
An initial dyno and motoring dyno is performed at the OEM stage, but this generally lasts no more than a couple of minutes at most. At a major US OEM engine assembly plant in the early 70’s, I saw a carousel dyno, where 8 engines are worked at once, run on a dry gas (this one used natural gas) while oil leaks, oil pressure, and initial run in were performed. As each engine was completed, it was removed and another installed.
Oil leaks can be checked by vacuum/pressure drop with 5 psig air pressure, oil pressure can be checked statically too. Originally, with manually adjustable ignition timing, that was performed at this stage, along with engine balance.
If the engine is built right and the human factor removed (the dreaded “Monday morning, and Friday afternoon” engine scenario) there is no reason the engine should be almost ready the moment it is installed. A site visit with a major piston ring manufacturer will show the research being done to allow rings to seal almost immediately, providing the proper cylinder wall finish is provided.
As a real life example: In the 60’s, where each engine was assembled by hand, with individual build up stations, and 60’s metallurgy, it was expected for an engine to last less than 100,000 miles, frequently with at least one valve refresher during that period. When emission restrictions became enforceable, the engine manufacturers had to tighten up the production processes and refine the build procedures. With today’s emission mileage warranty requirements, it is rare to see an engine ready for the scrap heap in less than 100,000 miles, with 200,000 not uncommon. Imagine the warranty costs if an OEM had to rebuild engines routinely at 60,000 miles. We still see smokers at less mileage than that, but a simple check of the required routine service shows that little attention has been paid. By simple observation, it appears that one manufacturer in particular seems to have a problem with smoker engines in vehicles approaching 5 years in age (I would guess about 75,000 miles).
Franz
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