Pistons are parts of an engine that move up and down against the inner walls of the cylinder, which is also an engine component. This causes the compression of air and fuel on the inside of the cylinder. Pistons are manufactured with two different techniques, forging and casting.

Cast Pistons

On most vehicles cast pistons are the stock piston type that the manufacturer installs. They are made by pouring an aluminum and silicon alloy that has been melted into a mold. Once the piston has its shape and the alloy hardens, the piston is released from the mold.

Forged Pistons

Forged pistons are manufactured by stamping a solid piece of aluminum and silicon alloy that is reinforced with nickel into the piston shape. Nickel is used because it helps to make the alloy less brittle.

Advantages of Forged Pistons

Forged pistons are stronger than cast pistons due to the nickel being added into the alloy mixture used to manufacture them. Forged pistons are used in applications that require high amounts of horsepower due to their strength and durability. Forged pistons are standard with high-end auto manufacturers such as Porsche and BMW.

Disadvantages of Forged Pistons

Forged pistons are more expensive than cast pistons to manufacture, and that cost is passed down to the consumer. Forged pistons must often be custom made to fit a vehicle and are not mass produced.

Buying Forged Pistons

Forged pistons can be ordered directly from the companies that manufacturer them or through high-end performance auto parts catalogs. Example high-end piston manufacturers are JE Pistons, Wiseco Pistons, and Arias Pistons.

Source:

MotorcycleProject.com: Cast Versus Forged Pistons- Wrenchbender

Stealth316.com: Piston Upgrade Guide

StrikeEngine.com: Forged Piston Manufacturers, Piston Dealers, Piston Design.

More Information:

FreePatentsOnlne.com: Multi-axially forged piston - Patent 6840155