You may think the break in is compleetly wrong because the cooled and heated parts of the engine in a normal situation the piston and sleeve will take a different shape. That is true, but because the piston is not heated to combustion temperatures there is still enough room to shape it right with only a short break-in process when firering up the engine.

As a discussion about my Ielasi 9CL piston some pages back that it was compleetly done wrong by only touching the upper edge is showing a perfect used piston after the first rod replacement and the engine is still going strong after 15 liter of use.

Lets say this process brings the engine into a perfect matching piston/sleeve set which can not be done by any machine when manufactured.

After break in:



Here the pic after the 1st 5 liter of use:
http://www.rctech.net/forum/attachme...d-dsc_1456.jpg