Instruction manual

EN
10
Engine Break-in
Your new engine needs to be broken-in to ensure a long life of all the components. The piston
and liner construction piston and liner construction is true ABC (Aluminum piston, Brass
Chromed liner), which requires a specic break-in procedure that cannot be fully accomplished
with bench runs.
Because the ABC piston and liner rely on the close fit of the piston to the liner to provide the
compression seal, the engines are built with a taper to the liner that requires the piston to
match the taper during the break-in process. For this to be accomplished, this process requires
repeated heating and cooling cycles, and must be done at a needle setting that is only slightly
rich of peak.
Breaking in an ABC piston and liner by running it rich does not provide the necessary parts
growth to accomplish the needed piston and liner fitting. Using a rich needle setting does not
allow for proper expansion of the liner, resulting in the connecting rod receiving the full force
of the piston when it moves past Top Dead Center (TDC). Allowing the engine to heat up will
expand the liner and reduce the load on the connecting rod, ensuring a proper engine break-in.
Doing the break-in with a light load on the engine (e.g. a smaller than normal propeller) makes
this task much easier. Please follow the steps below to ensure a successful experience.
1. Do the break-in process mounted on your
airplane and in the air.
2. Use a 10 x 6 prop for your break-in process.
This provides a light load, and high rpm
that when matched with the heat of the
engine will break-in the engine properly.
3. Use the proper recommended fuel with a
20:1 gas to oil ratio.
4. The proper break-in flight procedure is to
fly the airplane at full throttle through a
series of gure eight maneuvers (i.e. Cuban
Eight). These maneuvers in particular ben-
efit the engine because when climbing the
additional load on the engine will increase
the temperature and when diving the air-
plane the lighter load and higher rpm will
decrease the temperature, thus providing
the heating/cooling cycles required for the
break-in process.
5. Run two full tanks with the 10 x 6 prop and
then move to an 11 x 6 prop and repeat the
next two tanks.
6. You should now be ready to put on any of
the larger props and enjoy your engines full
performance.
Do not worry about an engine setting being
too rich during this process. When set
correctly, the engine will occasionally sound
as if it is misring (which it is). During the
climbing maneuvers this should go away and
might return during the diving maneuvers. If
it does not go away during the climbs then
land and adjust the high-speed needle by 1–2
clicks to the leaner position and take off and
fly again. Enjoy the break-in process—you are
doing a lot of flying.