V-8 ENGINES

V-8 ENGINES

ABSTRACT:

A V8 engine is a V-engine with eight cylinders. The V8 is a very common configuration for large automobile engines. V8 engines are rarely less than 3 litres in displacement and in automobile use have gone up to 8.5 litres or so. American cars until the mid 1970s almost universally had V8 engines, and many still insist on them.

The normal V-angle for a V8 is 90°. There are two classic types of V8s, which differ by crankshaft.

The cross-plane V8 is the typical V8 configuration used in American road cars. Each crank pin (of four) is at a 90° angle from the previous, so that viewed from the end the crankshaft forms a cross. The cross plane can achieve very good balance but requires heavy counterweights on the crankshaft. This makes the cross-plane V8 a slow-revving engine that cannot speed up or slow down very quickly compared to other designs, because of the greater rotating mass.

The flat-plane V8 design has crank pins at 180°. They are imperfectly balanced and thus produce severe vibrations. As they don't require counterweights, the crankshaft has less mass and thus inertia, allowing higher RPM and quicker acceleration. They're mainly used as racing engines, the most famous example being the Ford-Cosworth DFV.
The Coventry-Climax 1.5 litre V8 evolved from a cross-plane configuration to a flat-plane configuration in its latest versions.

for more info visit.
http://www.enjineer.com/forum