Combustion Chamber Layout. Simple side valve. Squish side valve. Few side valve aircraft engines. Overhead inlet side exhaust. Rover P3. Vertical swirl axis of o.h.v. two valve layout. O.h.v. squish. Reverse squish. Bathtub and wedge chambers. Weslake BMC A Series chamber. Higher performance derivatives. F3 race engines.

Port Induced Swirl. Hemispherical chamber with swirl port. AJS 7R. Jaguar XK and wide angle version. Coventry Climax V8. Porsche flat 8. Piston crown intrusion.

Downdraft Inlet Port. Prototype Jaguar V12. F1 and Indy engines. Early promise ends in disappointment even with four valves.

Flat (Heron) Head. Sam Heron. Rover 2000. Cosworth SCA. Ford Kent and Essex. Repco V8. Production Jaguar V12.

May 'Fireball' Chamber. Second generation Jaguar V12 (HE).

Four Valve Evolution. Wide angle types disappoint. Coventry Climax V8 combustion problems. Weslake and Duckworth both adopt narrow valve angle as the way forward. Barrel swirl around horizontal axis. F1 Splayed valves. Squish piston.

Still More Valves. Yamaha 5 valve. 6 and 7 valve schemes. Honda 8 valve (oval piston).

Ports and Gas Velocity. Influence of port on charge motion. Kinetic energy and charge density. Throttled and supercharged. Advantage of small ports.

Direct Injection. Revised charge motion from the four valve layout. Advantages for emissions and performance.

Wankel Rotary Engine. Mechanical advantages. Early promise for low emissions. Combustion issues. Fuel consumption. Loss of mainstream interest. Mazda successes.