Compression ratio was increased to 9.7:1 by reshaping the piston crown.

Much effort, and many different designs of piston crown, went into developing improved scavenging.

The excessive oil temperature was not just the result of heat coming from the piston crowns, but from the cylinder head and rocker boxes.

Revised piston crown shape to support a higher compression ratio of 9.6:1.

The increased temperature and pressure on one part of the piston crown causes uneven expansion which can lead to cracking, distortion or other damage.

The top surface of the block was machined at an angle, with the piston crowns angled in a "pitched roof" to match.

This melting point of 535 C can cause problems on the hot spots of the engine like piston crowns, valve seats, and turbochargers.

Sometimes an over rev can cause engine failure where the valve stems become bent as a result of colliding with the piston crowns.

The combustion chamber of this direct injection engine is a toroidal recess in the piston crown.

With Schnuerle porting, the piston crown may be of any shape, even bowl shaped.