Diesel Engine Troubleshooting

Diesel Engines Turbochargers Overhaul

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Only the most general instructions can be provided here, because construction details, wear limits, and torque specifications vary between make and model. It should also be remarked that American mechanics do not, as a rule, attempt turbocharger repairs. The defective unit is simply exchanged for another one.

However, there are no mysteries or secret rites associated with turbocharger work. Armed with the necessary documentation and the one indispensable special tool—a turbine-shaft holding fixture—any mechanic can replace the bearings and seals, which is what the usual field overhaul amounts to.

The holding fixture secures the integral turbine wheel and shaft during removal and installation of the compressor nut. Figure 9-9 illustrates plans for one such fixture, used on several Detroit Diesel applications. Dimensions vary, of course, with turbocharger make and model.

turbine holding fixture Diesel Engines Turbochargers Overhaul

Factory-supplied documentation should alert you to any peculiarities of the instrument, such as a left-handed compressor-nut thread or the need to heat the compressor wheel prior for removal. Special precautions include the following:

• Do not use a wire wheel or any other sort of metallic tool on turbo wheels or shaft. Remove carbon deposits with a soft plastic scraper and one of the various solvents sold for this purpose. Light scratches left by wheel contact on the turbo housings can be polished out with an abrasive.

• Do not expose the turbine shaft to bending forces of any magnitude. Pull the shaft straight out of its bearings. Use a double u-joint between the socket and the wrench when removing and torquing the compressor-wheel nut.

• Do send out the rotating assembly for shaft alignment and balancing (Fig. 9-10).

• Do exercise extreme cleanliness during all phases of the operation.

• Do prelubricate the bearings with motor oil and prefill the bearing housing prior to starting the engine.

• Do make certain that all fasteners and small tools are accounted for and not lurking within the turbocharger or its plumbing.

heins balancing Diesel Engines Turbochargers Overhaul

Written by Ed

February 23rd, 2011 at 2:35 am

Posted in Air Systems

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