JE Pistons has introduced a revolutionary new, solid-film-lubricant coating called Perfect Skirt . The patented technology—including the formula, tooling, and application process—was developed in-house and eliminates piston slap and false knock.

“The motivation was to develop a robust skirt coating that could be applied and bonded thicker and allow the forged piston to be installed at the same or less cold clearance than a cast piston, as measured on the coating,” says Nick DiBlasi, product manager at JE Pistons.


Perfect Skirt is a solvent-based coating that is permanently applied to the piston skirts in a 3-stage bonding process. Unlike many coatings, it is not a temporary layer for break-in. It will stay bonded to the piston through its service life. “This is not a typical spray-on type application,” says DiBlasi. “The skirt panels are transformed from a bare aluminum running surface to a permanently bonded solid-film running surface.”

Perfect Skirt will complement JE’s other well-known skirt coating called Tuff Skirt—which is typically is used on custom orders where the numerous options available change the piston foundation too much to allow proper application of the coating.

“Perfect Skirt requires tooling designed to fit each piston family and is used on our catalog shelf part line, which we designed specifically for it,” explains. DiBlasi.



The new coating from JE is unique in that the material is applied to a specific thickness that reduces the running clearance of the piston inside the cylinder. However, don’t be misled into thinking that JE simply applies a thicker layer of standard skirt coating.

“The Perfect Skirt coating formulation has the unique ability to automatically and precisely fit itself to the specific cylinder in which it’s installed,” says DiBlasi.



When an engine is first fired up, the piston coating in contact with the cylinder wall will quickly adjust to a precise form and provide minimum running clearance. “At this point, the coating has settled into a uniform and equalized pattern, providing very low friction and quiet operation throughout its service life,” adds DiBlasi. By reducing clearances, the Perfect Skirt coating reduces cold-start wear and more importantly the chance of false knock readings in late-model engines.

For more info on Perfect Skirt technology and a full list of supported applications, click HERE .