AIR INTAKE FILTERS Back
It has been a well-known fact for many years that a major cause for excessive engine wear and early failures is the direct result of poor or no maintenance of intake air systems. The ingestion of foreign materials in sufficient quantity through a faulty filter system will in a matter of hours, destroy a 2-cycle or 4-cycle gasoline or diesel engine. To appreciate how this is possible it must be understood that the air to fuel ratio is thousands of gallons of air for every gallon of fuel consumed.

While wear is a major consideration, of equal importance is the loss of fuel economy and horsepower that can be directly attributed to restricted air filter systems.

There are two basic types of air filter systems in use -wet and dry. Of the two the dry system, which uses a replaceable element is most popular and efficient. Efficiency levels at installation are in excess of 99% for the dry type and about 96% for the wet type filter.

 

The efficiency of the dry type is derived by the use of a specially treated paper, pleated to increase the area of filtration. Contrary to popular belief, the dry type filter does not lose its efficiency when it gets dirty as the build-up of foreign material actually helps to stop even smaller particles from entering the air flow. There is, of course, a limit to what is allowable as previously mentioned, when the air flow is restricted to excess, loss of horsepower and fuel economy result. Time elements and efficiencies can best be determined by close adherence to manufacturers recommendations.

The major problem with the wet type or oil bath cleaners is their inability to stop the very small particles from entering the air system. As the air enters the system it travels across the oil bath where the heavier particles are trapped in the oil. Regular service intervals are imperative on the oil bath, as build-up of particles in the bottom of the cleaner will cause a rise in the oil level and a pullover of oil and contaminants into the air flow to the engine.

Regardless of which type of unit is used, the areas in back of the filter are as critical to good performance as the filter itself. On trucks the location of the air intake is very critical, that it is not located in line with exhausts, heavy dust concentration or water spray. Air leaks of any kind from defective mounting gaskets to cracks in metal connecting pipes to holes in flexible tubing will render all but useless the best maintained filter.

  (P37)