Don't worry... you can continue the factory break in procedure by any
route you choose... the key is high revs... you see at the factory
they have already run the engine a high rpms to help seat the rings...
they are not thrashing your engine... you're doing what your engine
requires... The purpose of high rpms is initial seating of the piston
rings to the cylinder walls. The run is conducted at full power
because that is where greatest B.M.E.P. (Brake Mean Effective
Pressure) occurs and a high B.M.E.P. is necessary for good piston ring
break-in.
The cylinder walls of a new engine are not mirror smooth as one might
imagine. A special hone is used to put a diamond like pattern of
"scratches" over the entire area of the cylinder wall. The cross hatch
treatment of the cylinder walls plays an important role in proper
break-in of piston rings to cylinder walls. I mentioned that B.M.E.P.
was necessary to the "break-in" process. Here is how it works.
If you cutaway a piston, ring and cylinder wall and inspect under
magnification you see something to the effect of "saw teeth"... Given
that a film of lubricating oil holds the piston ring away from the
cylinder wall. Proper break-in of piston ring to cylinder wall
requires that the ring rupture or break through this oil film and make
contact with the cylinder wall. During such "metal to metal" contact,
the little peaks on the ring face and cylinder wall become white hot
and rub off. This condition will continue to occur until the ring face
and cylinder wall have established a smooth compatible surface between
each other. At this point, break-in is said to be relatively complete
and very little metal-to-metal contact will occur hereafter. In fact,
as the break-in process progresses, the degree of metal-to-metal
contact will regress.
How do you know if break is done??? take a compression test... if your
engine shows factory compression then break in is complete... if your
engine shows less than factory compression then more break in is
require...
