Why do some forged pistons make noise?
Forged pistons expand more when hot so they require a greater physical clearance than a cast piston. From 2004 to 20006 we used custom forged pistons made to our specifications from a proprietary aerospace aluminium alloy, which operated at the industry’s tightest piston to bore clearances. They were reasonably quiet and very durable, but when cold they made a slight operational noise. There were some other pistons on the market which were quieter but were not as durable, so we believed it was better to install the strongest piston available and accept a small amount of operational noise. In 2005 we began working with Mahle Motorsport and in 2006 we released a forged piston for the Ford DOHC engine. This was a good piston but it developed cracks in the skirts over time. Unable to achieve a satisfactory product to handle the power we sought, we went straight to the ultimate in piston engine manufacturers, Cosworth Engineering in the UK. They evaluated our current problems and designed a
