Turbocharger: Testing and Inspection

Fig. 4 Exploded view of turbocharger. 1984---86 4-140 engines:

Fig. 5 Checking turbocharger bearing radial clearance. 1984---86 4-140 engines:

4-140 ENGINE
Turbocharger Bearing Radial Clearance Check
1. Remove turbocharger from engine.
2. Remove wastegate actuator rod retaining clip, then remove rod from wastegate arm, Fig. 4.
3. Remove two bolts connecting the turbine oil outlet fitting to the center housing and remove the fitting. Attach a dial indicator (Tool 4201-C) to the center housing so that the indicator plunger (Tool T79L-4201-A) extends through the oil outlet port and contacts the shaft Fig. 5.
4. Manually apply pressure equally and simultaneously to both the compressor and the turbine wheels to move the shaft away from the dial indicator plunger as far as possible.
5. Set the dial indicator to zero while holding the shaft away from the plunger tip.
6. Manually apply pressure equally and simultaneously to both the compressor and turbine wheels to move the shaft towards the dial indicator plunger as far as possible. Note the maximum reading on dial indicator.
7. Manually apply pressure equally and simultaneously to both the compressor and turbine wheels as required to move the turbine wheel assembly shaft away from the dial indicator as far as possible. The dial indicator should return to zero.
8. Repeat steps 2, 3, 4, and 5 to make sure an accurate measurement has been made. If the bearing radial clearance is less then 0.003 inch or greater then 0.006 inch, replace the turbocharger assembly. Continued operation of a turbocharger having excessive bearing radial clearance will result in severe damage to the turbocharger.

Fig. 6 Checking turbocharger bearing axial clearance. 1984---86 4-140 engines:

Turbocharger Bearing Axial Clearance Check
1. Remove turbocharger assembly from engine.
2. Remove five bolts connecting the turbine outlet elbow assembly and remove the elbow.
3. Attach a dial indicator (Tool 4201-C) to the center housing so that the indicator plunger extends through the housing contacts the shaft, Fig. 6.
4. Manually push the turbine wheel assembly as far away from the dial indicator tip as possible.
5. Set the dial indicator to zero while holding the turbine wheel away from the tip of the plunger.
6. Manually push the turbine wheel assembly toward the dial indicator tip as far as possible.
7. Repeat step 3 and check that the dial indicator returns to zero.
8. Repeat steps 3, 4, 5, and 6 to make sure an accurate measurement has been made. If the bearing axial clearance is less than 0.001 inch or greater than 0.003 inch, replace the turbocharger assembly. Continued operation of a turbocharger having excessive bearing axial clearance will result in severe damage to the turbocharger assembly.