Patent ID: 8863381

Claim:
A method of making an aluminum piston without the use of a dissolvable salt core, the method comprising: placing an oil gallery core in a mold; introducing liquid aluminum into the mold around the oil gallery core such that no dissolvable salt core is present in the mold; connecting the inlet tube to a supply of water; and allowing the liquid aluminum to solidify, the oil gallery core forming a channel in the piston, wherein: the oil gallery core comprises a metal tube connected to a hollow inlet tube and a hollow outlet tube; the metal tube comprises a variable cross-section along substantially the entire length of the metal tube such that the metal tube has a relatively larger diameter where the inlet tube and outlet tube are connected, and a relatively smaller diameter between where the inlet tube and outlet tube are connected to the metal tube; and the inlet tube and the outlet tube are connected to the supply of water and a water outlet respectively with adaptors, each adaptor having a seal formed between the adaptor and the inlet tube or outlet tube.