As your engine starts for the first time, the break-in process begins. For all ABC-type engines proper break-in is critical in
obtaining the best performance and longest life. Nearly every part on your engine was produced using CNC (computer
numerical control) production machinery. These programmed machines are highly accurate and produce individual engine
components that fit together almost perfectly. Despite such accuracy, metal components (primarily the piston and cylinder-
sleeve) require minor “seating” (e.g. mating parts perfectly that operate together) and heat-cycling to relieve internal stresses
in the metal, due to their fabrication. Therefore, “break-in” can be summarized as the process of “seating-in” and heat-cycling
of all engine components from ambient (outside air temperature) to normal operating temperature, by running the engine time
after time, until optimal fit and stress relief are achieved.
Your new Fantom engine is built using the latest ABC technology (Aluminum piston - Brass sleeve - Chrome plated inner
sleeve wall). All ABC engines are designed with a tapered sleeve, so that the piston is pinched at the top of the piston stroke,
known as Top-Dead-Center. This area, at TDC, is called the “pinch-zone”. You can feel it by turning over the crank by hand
and noting how the crank gets hard to turn once the piston reaches TDC. Since ABC engines don’t have piston rings, this
“pinch” is necessary, in place of the rings, to create compression in the combustion chamber. The most critical aspect of a
model nitro engine is compression, because without it an engine will not run properly and is nearly impossible to tune, and in
some cases will not run at all. Both the fuel and glow plug require compression to work effectively. Proper break-in ensures
that maximum compression and the longest usable piston and sleeve life are achieved. The piston and sleeve are made of
aluminum and brass because these are two metals that work together perfectly for this application, due to their ideal
expansion characteristics when heated by normal engine operation. The chrome plating serves as a very slippery and wear
resistant surface for the piston to efficiently operate against. The ideal expansion rates of aluminum and brass help maintain
good compression throughout the engine’s normal operating temperature range. Metal expands when it is heated and by
matching the piston’s expansion (determined by the silicon content in the aluminum alloy) to the expansion of the chrome
plated brass cylinder-sleeve, the best running-fit is obtained once the engine reaches normal operating temperatures of 220º-
260º F. Getting the engine quickly into its normal operating temperature range during break-in is critical, because if the engine
is ran too cool, the sleeve will not expand enough, causing the piston to wear against the smaller diameter sleeve size. This
commonly happens when someone tries to break-in an engine using the method of letting the engine idle for break-in, as
instructed by some engine manufacturers.
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269. 649. 9583
