Show carburetor air filter keeps keep out much grit analysis of the incombustible de posit in the cylinder of an auto engine after the carbon had been burned out ont showed it to consist of ordinary sand clay dust and limestone dust which had undoubted lly Ily been drawn into the motor through the carburetor As t the sand Is highly abrasive it Is obviously responsible for most of tho the wear on pistons rings and cylinder walls walla tho me entrance of sand and dust into bito tho the carburetor air intake can be prevented by providing a filter of the kind shown in the drawing this method has been tried out and found highly satisfactory the space bet between veen the dash and instrument board was used na as a filtered chamber and was waa I 1 connected to too the carburetor air intake NT BOARD AIR F LIU air filter on etar keeps grit ou motor with a length of flexible metal tubing this space was sealed to prevent air from coming in except through the tha filter which was provided in we the bottom it consisted of several layers of closely woven cloth with a piece or of wire screen to make the filter more rigid after a days run a of dust was brushed from the underside of the filter later when carbon was aga again in burned out there thera was no trace of any unburned deposit it 11 P cole paterson N J in popular mechanics magazine |