Cummins made a change to their N14 piston skirt design. As Cummins doesn't sell the skirt separately, they didn't give the skirt a part number. Cummins only sells the skirt as part of a complete piston kit. Although this change was made some time ago, it is still causing some confusion. Cummins didn't change the piston kit part number when they changed from the old skirt design to the new one. This resulted in both the old and new piston skirt designs having the same piston kit part number. Highway and Heavy Parts does carry the new piston skirt design and it is available for purchase without having to purchase the piston kit. The HHP part number is "MCBN14SKIRT". We also include the new style skirt in all our N14 engine rebuild kits. Unfortunately, there isn't a way to know what piston skirt the engine was originally built with by the engine serial number. The piston skirt will need to be visually inspected to see which design it is. This can be accomplished by removing the oil pan and looking up at the skirt or by completely removing the piston assembly from the engine.
New Skirt Design (Left) Obsolete Old Design (Right)