Pistons, what to get and why.
Cast vs. Forged What’s better and why:
Two-stroke Pistons Because of a cast piston’s ability to contain higher silicon content compared to forged pistons, and because two strokes have lower cylinder pressures when compared to four-strokes, cast pistons are ideal for two-stroke engines.
Cast pistons are gravity cast from an aluminum alloy with up to 18% silicon content. Silicon is important because:
• It decreases thermal expansion, which changes the geometry after the piston reaches operating temperature. With low thermal expansion characteristics, Cast pistons can be run at tighter tolerances compared with forged pistons. This creates better power and performance, also making them less susceptible to rattling or breaking.
• Silicon gives the pistons better wear characteristics and prolongs piston life by decreasing wear on the piston skirt.
Four-stroke Pistons Four-stroke engines have much higher cylinder pressures when compared to two-strokes and are generally manufactured from forgings. To handle the internal pressures of a four-stroke engine, Vertex’s four-stroke pistons are forged from the highest quality 2618 aluminum alloy for superior strength and durability. Vertex uses unique piston profiles and compression ratios, offered in A, B, C and D sizes, to maximize power and performance while reducing blow-by and oil consumption.