Question 48Motor Plants - 1st Asst/Chief

The correct answer is A) knurling the piston skirt surface. Knurling the piston skirt surface can help extend the service life of a worn aluminum piston for an auxiliary diesel engine when no replacement parts are readily available. Knurling creates a rough, textured surface that increases the friction between the piston and the cylinder wall, improving the piston's sealing and reducing wear. The other options are not suitable for extending the service life of the piston. Increasing the dimensions of the ring land grooves (B) would not address the wear on the piston skirt. Building up the piston skirt with a liquid epoxy material and then remachining (C) may temporarily fix the issue but is not a long-term solution. Turning down the piston skirt to concentric values (D) would reduce the piston's diameter, potentially leading to poor engine performance and further wear.