Piston Selection

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: Identifying Cylinder Bore Measuring Directions

Courtesy of FORD MOTOR CO.

NOTE: For precision fit, new pistons are divided into 3 categories within each size range based on their relative position within the range. A paint spot on the new pistons indicates the position within the size range.

Choose the piston with the correct paint color.
- Refer to ENGINE article for the procedure.

Fig 2: Identifying Piston Grade Size

Courtesy of FORD MOTOR CO.