Question 47Motor Plants - 1st Asst/Chief

You are correct, the answer is A) improve skirt lubrication. The piston skirt is the lower portion of the piston that contacts the cylinder wall. Knurling the surface of the piston skirt helps to improve lubrication between the piston and cylinder wall. The knurled surface creates a better oil film, reducing friction and wear on the piston and cylinder. The other options are incorrect because: B) transmitting forces evenly is not the primary purpose of knurling, C) allowing for heat expansion is more related to the piston design, and D) improving the piston seal is not the function of knurling the skirt.