DRAWBACKS OF SPEED.

Hawera Star, Volume XLVII, 17 March 1928, Page 14

DRAWBACKS OF SPEED.

INCREASED PRODUCTION COSTS

Although there are undoubted advantages to he gained by increasing the normal maximum speeds of car engines, they are not unaccompanied by drawbacks, and 1 one of these is concerned with price. To • secure xhe same standard of durability with an increase of engine speed and power output necessitates variations in design that increase manufacturing costs. For example, a stiffer crankshaft is needed, larger bearing areas-, larger valves, and, with the latter, heavier springs and valve-operating gear, and a heavier camshaft. The crank case- also needs to be stiffer for the same reason as that applying to most of the other necessary variations, namely, to withstand the heavier stresses due to increased inertia and centrifugal forces. To prevent those forces from being increased unduly certain parts have to he .made lighter, which again adds to the cost; lighter pistons usually mean a larger proportion of throw outs in course of manufacture, and light connecting rods call for the use of a special alloy or machining them all over.