Paper 5: The Hillman 875 cm3 Engine

Abstract

The paper covers the constructional considerations, design and development of the engine to be installed in a rear-engined vehicle. The need for minimum weight and size coupled with adequate power output resulted in the decision to use light alloy diecastings wherever possible. The various methods of diecasting are considered and the methods used for the various components are discussed with the reasons for their use. Problems with cast-in cylinder liners, machining considerations and the implications of laying the engine at an angle in the car are covered. With regard to performance, several factors are discussed: the reasons for adopting the four-stroke cycle, four cylinders, water cooling; determination of capacity from power required data; the use of a single overhead camshaft; combustion chamber shape and compression ratio; port shapes and determination from air flow research. Then follow the various stages of development work and endurance testing.