guys,
got this info from a reliable source. This guy works at Honeywell TurboMachinery Engineering. He knows his stuff.
Break in 101:
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Basically, all the engine parts like the crank, the rods, and the pistons,
haven't really taken a set yet. That is they might stretch or change a
little (very little) due to some small stresses from manufacturing.
This process is called stress relieving. Also, the piston rings are matching
up to the cylinder walls right now (scraping off the smallest amount of
metal or deforming it, maybe .0003"). This is when they are making a good
seal around the pistons, that's why cars usually get a little faster after a
couple thousand miles, and then deteriorate again as crap builds up inside.
I think the key to breaking in an engine is to use regular oil, not
synthetic oil for the 1st 500 miles, then changing it, and either repeating
for another 500 miles or just putting in the synthetic and going. The
problem with putting synthetic in right away is that slight scraping that
matches everything up can't occur as well...
To start with you want to run the car at different RPMs without overusing
any one range of rpms. The faster the rpm, the faster the piston is going,
the more force on the rods and the more everything stretches. So as you go
through the rpm range, the whole thing is matching up in slightly different
places as the forces increase...
I read about cars that have never been to high rpms and they get a new
owner, the piston rings start travelling slightly higher in the cylinder and
they hit a small lip that has developed from all of the low rpm running,
when it hits that lip, chunks start coming off rather than slivers...
Anyways, that was probably way more than you wanted to know but....
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makes sense huh?
George
