BSA Bantam Race Preparation Manual

Thank-you Trevor...!
Your emphasis on increased area of domed pistons had me wondering why not use the flat-topped piston crown? I had asked this question many years ago and was told the dome improved turbulence but there are many other ways to improve turbulence although that thought is based on my diesel engine work where we had the combustion bowl in the piston crown. This concept of piston-bowl shape and combustion system was sold to Ford after we went belly-up in Montreal.

  The intake port  had a lot of development years invested in its shape as had the combustion-chamber shape (which improved turbulence) and the  diesel injection system was quite revolutionary Re the latter: we developed a Controlled mode of injection rate that had an early squirt which got the fire going  before TDC but had the main injection quantity controlled for rate such that the peak combustion pressure occurred AFTER TDC at what we thought was the right place.. The indicator diagram showed that there was  no rapid increase of combustion pressure before TDC.... where a lot of energy is lost in conventional systems.

Of course, the diesel engine of that era was limited by other factors to be SLOW  compared with petrol engines and the system we developed then was laughable when compareed with microprocessor controlled systems today but the ideas are still applicable today.

Cheers!

JayBee...