The turbochargers used in the Navy today may operate with temperatures as high as 1200F and

Figure 3-28.Checking bearing, axis end play.

Figure 3-29.Checking shaft radial movement.

speeds up to 75,000 rpm. Therefore, it is of utmost importance that turbochargers be maintained in proper working order at all times. If a turbocharger is allowed to operate without lubrication, cooling, or the proper clearances, it not only could be completely destroyed in a matter of minutes but also could possibly cause extensive damage to other machinery and personnel.

All oil lines and air duct connections should be inspected and free of leakage. The air filter should be clean and in place and there should be no build-up of dust or dirt on the impeller. Turn the impeller by hand and check for binding or rub-bing and listen for any unusual noises.

When the turbocharger is operating, listen for any unusual noise or vibrations. If you hear a shrill high pitch whine, shut down the engine at once. The whine may be caused by a failing bearing, and serious damage may result. Do not confuse the whine heard as the turbine runs down with that of a bad bearing.

Noise from the turbocharger may also be caused by improper clearances between the turbine wheel and the turbine housing. The clearances should be checked at predetermined intervals in accordance with the PMS. Checking bearing axial end play and shaft radial movement are shown in figures 3-28 and 3-29, respectively.

Crankcase vents should not be directed towards the turbocharger air intakes, as the corrosive gases may cause pitting of the blades and bearings, thereby reducing the life of the turbocharger.