Forrest wrote:

> A friend and neighbor, who is a retired engineer and has knowledge and
> experience with things mechanical, including cars, told me just now
> that he broke in his 1999 Ford 150 Lightning truck by changing the
> original factory oil at 1000 miles and then again at 2500 and then at
> 5000 and has kept to 5K, with synthetic, for changes since.
>
> I know that engines are machined to greater tolerances than those of
> 20 years ago,

Actually, they're not. Most of the critical engine clearance
specifications (piston-to-wall, ring gap, bearing clearnace) for a 1966
engine are essentially identical to those of a 2006 engine. What has
changed is twofold:

1) quality of OIL is vastly improved and continually improving.
2) consistency of assembly- IOW, its easier for a manufacturer to hit
the specifications right on the mark on EVERY engine that rolls off the
line these days.

For what its worth, though, I break in all new engines (whether just
purchased or a freshly rebuilt 1966 engine) pretty much exactly the way
your neighbor did. If its a truly freshly-assembled engine that I've put
together and has never been run at all before, I do the first oil change
after one *hour* of break-in time, believe it or not, to get all the
assembly lubricant and initial wear products out. Then 500 miles, then
1000, then 2500-3000, then normal oil changes. It may not be a
significant benefit, but it definitely cannot hurt. Given the amount of
visible metal in the oil that comes out of any freshly assembled engine
(including 2006 engines) I would AT LEAST change the filter after a few
hundred miles on any new car.