pdd

iTrader: (3)

blk~2000~Z28

It is cutting little reliefs into the top of the piston so that radical cams do not cause the valves to contact the top of the piston.

Old SStroker

"flycutter" is a term for a rotating cutter with one or more teeth on the outside diameter. Often it refers to valve notching as mentioned.

Imagine a valve with teeth cut into the outer edge. Mount it in the head, screw the head back onto the engine, chuck the cutter stem in a hand drill, put the piston at TDC, and slowly feed the cutter into the piston until you reach a preset stop. You could do this using a Piston Notching Tool tool from Isky.


http://www.iskycams.com/pdfcatalog/PAGE17.pdf

"Flycutting" is often be done on a milling machine with the piston tilted to the proper angle if you have that equipment.