Pistons

56mm-small.jpg (17201 bytes) New custom pistons I designed for the CD2a. Compression after machining is about 12:1.
Piston-175-mill-1.jpg (31282 bytes) Here's a picture of the piston on the milling machine getting the plug electrode clearance notches machined
Piston-plug-notch-1.JPG (23637 bytes) The final product.

The dome extends high enough into the combustion chamber that the notch is needed to prevent the plug electrode from hitting the crown of the piston.

Flat top surface allows for acceptable flame propagation in the chamber.