to put a hard iron skirt surface opposite the silicon of the block to prevent scuffing. The plating was a four layer electro-plating process. The first plate was a flash of zinc followed by a very thin flash of copper. The third and primary coating was hard iron, thick. The final layer was a flash of tin. The zinc and copper were necessary to adhere the iron while the tin prevented corrosion before assembly of the piston into the engine. Piston plating was done on a 46 operation automatic line. From Tonawanda, the engines went to the Chevrolet assembly plant in Lordstown, Ohio. Eudell Jackobson of GM engineering pointed out one of the early problems with unexplained scuffing and discovered excessive pressure on the bore hones was causing the silicon to crack. This need to both develop and actually manufacture the engine was a product of the program schedule. He said, "...We were trying to put a product into production and learning the technology simultaneously. And the pressure becomes very, very great when that happens. The hone-pressure problem was solved before engines actually went out the door, affecting pre-production engines only." See also GM engines References Chevrolet engines Straight-four engines Gasoline engines by model