ABC

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The term ABC in reference to an R/C nitro engine means aluminum, brass and chrome, the three metals used in the manufacturing of the engine's piston, cylinder sleeve and cylinder head.

Nitro engines manufactured by this method do not use piston rings to aid in compression. Because of this, ABC engines are intentionally built to very tight tolerances, requiring strict adhesion to the manufacturer's break-in recommendations to ensure long engine life and to avoid catastrophic engine damage.