THE fuel consumption prevailing today is no better than it was five years ago. Higher road speeds are responsible. Cars in the hands of owners today are below potential economy between 10 and 15 per cent. Minor adjustments can correct this.
Phasing of the burn with valve and piston movement is necessary for economy. Spark-plug position relative to the whole chamber is important. Spark-plug points position inward is important. The spark-plug gap width must be worked out. Mixture “fish hooks” to determine leanest mixture that will burn without raggedness, are the yardstick.
Mixture distribution is important. The attitude of today is that a specific type of manifold does not exist. The manifold must be “tailored” to fit individual conditions. Offside mixtures out of the carburetor is real problem of distribution.
Exhaust dilution of the mixture is the handicap to clean operation with lean mixtures. Timing is the most important avenue of progress.
