MAKING LESS NOISE

Timaru Herald, Volume CXXXVI, Issue 19154, 9 April 1932, Page 17

MAKING LESS NOISE

WATCH THE ENGINE. Traffic noises has interested the Ministry of Transport recently, as it has interested for a long time scientists who make a study of the effect of noise on nerve strain, says an English writer. A large part of the noise made by motor traffic can readily be prevented. The following suggestions, if generally adopted, will do much towards making streets quieter. Avoid racing the engine before starting the car. Many drivers make a practice of this in a mistaken belief that it ensures reliable operation under load, but it is entirely unnecessary, especially in warm weather, nor is it required in cold weather, for a slight application of the choke tvill give better results. Racing an engine is always detrimental, particularly when it is cold.

Always set the throttle for a very low idling speed so that the engine will not roar when it is declutched. Never open the throttle and race the engine when shutting it down. This does not make the next start easier, as some drivers seem to think.

It is a great mistake to accelerate a car excessively in bottom and second gears before engaging top. In stopping the car, except in emergencies, let the closely throttled en-

gine slow down the car before the stopping place is reached, thus avoiding violent brake applications.

Clashing of gears can be entirely eliminated if the driver will use judgment as to engine speed and car speed, and change only when they approximately correspond. Try different engine and car speed relationships and varying degrees of quickness in engaging the gears, until the conditions giving the utmost smoothness and quietness are determined and make the changes accordingly.

Noise is not the only problem of the streets. A car with a foul exhaust can be a menace to health as well as to comfort. It is incumbent upon every motorist to do his bit to minimise this evil.

Incomplete combustion of petrol and the vaporisation of partial burning of excess cylinder oil are the causes respectively of the presence of carbon monoxide and of irritating and illsmelling vapours in the “breath” of engines.

The chief cause of incompletely burned fuel is over rich carburetter adjustment, but irregular or weak ignition and imperfect vaporisation are contributing factors. The use of as lean a fuel mixture as practicable, the maintenance of perfect ignition, and the use of sufficient heat to ensure complete vaporisation are the remedies. As to the obviation of oil fumes, the use of the best oil, capable of standing up under high temperatures, and of piston rings so fitted as to prevent the entrance of excess oil into engine combustion spaces, together with such adjustments as bearings and pump pressure as will insure against an oversupply of oil to the cylinder walls, will prove effective.

Fortunately, waste of fuel and oil, which makes a car with a foul exhaust a public nuisance, also makes it wasteful and uneconomical to operate, so that self-interest as well as self-respect can be appealed to.

Ignition wires where they run near exhaust or other engine pipings rapidly become scorched, and eventually will short circuit at these scorchings and cause mis-firing. It is a good plan to tape them at danger points with adhesive tape, afterwards twice shellac varnishing the binding.