What type of aluminum are pistons made of

This is a valuable property since most pistons are formed from squeeze casting. Aluminum pistons are made from alloy with a relatively high concentration of silicon. Aluminum high in silicon improves wear resistance, compared to low concentrations of alloying element.

Another very stiff, lightweight alloy, MMC is also banned by Formula 1 but continues to draw interest in other areas of motorsports where the rules are more open.

For many years, top engine builders have preferred billet pistons over forged versions—and probably not for the reason you might think. This is half our business. The debate over billet vs. In addition to improved materials and advanced construction methods, specific features have been developed to boost horsepower through either thermal dynamics, reduced weight or reduced friction.

Following are some examples of design elements often unique to racing pistons:. Although some exotic engines run 2-ring packages, the majority of racing applications stick with the tried-and-true 3-ring setups.

What has changed dramatically is the thickness of those rings, especially in Pro Stock and other non-endurance engines. Through normal secondary motion piston rock , the top ring tends to become momentarily unsettled as it rapidly changes direction through TDC.

As this occurs near peak firing, combustion pressure tends to make its way past the top ring until it re-settles. Combustion pressure also gets through at the end gap of the ring.

Less weight is always desirable but using a smaller or thinner wrist pin may compromise strength and engine durability. Again, more design changes to reduce weight and friction but these efforts are usually dictated and restricted by the engine architecture, such as length of the cylinder sleeves and the stroke.

Some engine builders want to reflect the heat away from the piston, preferring that the valves and cylinder head dissipate the heat to the coolant instead of the pistons and rings through the cylinder wall. Thermal coatings are designed to repel heat from the piston crown, and in some cases the combustion chamber as best as possible.

Side-by-side, it's almost impossible to tell the difference between and alloys. The forging on the left is , while the right is While they look the same, their material properties are significantly different. In extremely demanding race applications, such as this billet 2JZ Toyota build that will see almost psi of boost, a alloy is the way to go. It's more ductile, which allows it to resist cracking, and can tolerate high cylinder temperatures.

This gives the pistons exceptional toughness for performance street and some racing applications, while preserving street manners wear rate, low expansion, low noise. Left is a stroker piston. Right is a billet puck of aluminum that has yet to undergo any machining. This billet racing piston is the perfect usage of alloy. It is fully machined for absolute lightness and takes advantage of 's excellent strength characteristics.

Recent Posts. February December June March October This gives the pistons exceptional toughness for performance street and some racing applications, while preserving street manners wear rate, low expansion, low noise. Piston alloy is really just one of many decisions you will need to make on your way to assembling your next engine. But armed with the right information — that engine has a superb chance to make great power and put a smile on your face all at the same time.

This article was sponsored by JE Pistons. Pro Con. Stronger Piston Noise When Cold wider clearances. Excellent Wear Rate Less Ductile. Quieter tighter clearances Lower Strength at High Temperature. Slightly lighter Less Fatigue Resistant than Sponsored Content: Got Grease! Baking Soda Cuts Grease… and Time. Magazine Current Issue Past Issues.

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