Piston - Selection

WARNING: This page is about a different car, the 2004 Mercury Marauder, 2004 Mercury Grand Marquis, and 2004 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The cylinder bore must be within the specifications for taper and out-of-round before fitting a piston.

Select a piston size based on the cylinder bore.

Fig 1: Selecting Piston Size Based On Cylinder Bore
Courtesy of FORD MOTOR CO.

NOTE: For precision fit, new pistons are divided into three categories (grade sizes). A paint spot on the new pistons indicates the grade size. Choose the piston with the correct paint color after measuring the cylinder bore diameter.

Choose the piston with the correct paint color.
- Refer to the appropriate ENGINE article for more information.
Fig 2: Identifying Piston Paint Color Location
Courtesy of FORD MOTOR CO.