Breaking in an Engine

stooie said:

1. This is an extremely contentious topic.

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It is ... mostly because engines are built differently than they were in the 20th century and so many fail to change their understanding accordingly.

Posted before, but ... in 2006 I was able to witness in person the hand build of a Mercedes AMG 6.3 V8. When finished (and builder's nameplate attached) the engine was attached to a fixture and spun up electrically for a systems check. It was then broken in. Surely one wouldn't expect the new owner of a multi bucks hot rod to be told s/he couldn't run it hard for a while.

This may not be relevant to the stuff GM or Chrysler build, but that's of little relevance or interest here.

When should I go to full synthetic?





Just messing with you all. Break in is a valid concern to a new owner spending so many thousands on their toys. I find oil threads, tire threads, and engine break in threads interesting. BTW, we just rode our brand new 2018 GS 654 miles over 3 seperate rides on twisty back roads in western NC.
Nothing broke so it's broke in, right?

CABNFVR said:

BTW, we just rode our brand new 2018 GS 654 miles over 3 seperate rides on twisty back roads in western NC.

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That's 54 miles over the initial service! That bike is DOOMED but don't worry, give it to me and I'll assume the responsibility of paying for the new engine it'll need 250,000 miles from now.

CABNFVR said:

When should I go to full synthetic?





Just messing with you all. Break in is a valid concern to a new owner spending so many thousands on their toys. I find oil threads, tire threads, and engine break in threads interesting. BTW, we just rode our brand new 2018 GS 654 miles over 3 seperate rides on twisty back roads in western NC.
Nothing broke so it's broke in, right?

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I kid, I kid..

Too bad they didn't do a third engine--where the break-in is based on low, steady RPMs/babying the engine. The older technology (materials/oils) needed break-in to "seat" the rings (at least from my old school training). The lore was that if you didn't vary the RPMs and spin it up once in a while during break-in, you wouldn't seat the rings and you would forever deal with excessive oil use and lack of compression. The concept also included using mineral oil until break-in because the synthetics wouldn't allow enough friction for the break-in to occur (as mentioned in the article).

toolman_57 said:

Too bad they didn't do a third engine--where the break-in is based on low, steady RPMs/babying the engine. The older technology (materials/oils) needed break-in to "seat" the rings (at least from my old school training). The lore was that if you didn't vary the RPMs and spin it up once in a while during break-in, you wouldn't seat the rings and you would forever deal with excessive oil use and lack of compression. The concept also included using mineral oil until break-in because the synthetics wouldn't allow enough friction for the break-in to occur (as mentioned in the article).

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One break in issue that seems to never be addressed is the sealing of the rings in the grooves between the piston lands. Part of the reason mineral oil or special break-in oil was used was to allow a slight buildup of varnish in the ring grooves to enhance sealing behind the rings - not the wear-in of the rings outer surface to the cylinder wall.

Whether more modern materials and machining renders this issue moot is never addressed in interweb discussions.