Show whistle helps measure pressures in engines how to measure the volume of the compression space pace above the pistons of an internal combustion engine without removing the cylinder head has been solved by the invention of a whistling gauge the rate of vibration of the air 1 in the cylinder head Is compared with that of air inan in an adjustable ju stable and calibrated chamber of known volume by employing two identical whistles one attached to one sparkplug spark park plug port of the engine and the ot other herto to the adjustable chamber be the whistles whistle are blown by air having a common supply and constant pressure says popular mechanics chanice cs the pitch of the notes of the whistles on the two cham chambers beri depends upon the volume of air contained in them thus when notes of f the kanii same pitch are produced the volumes of the two chambers are equal |