Connecting rod Inspection of Cummins 1500kVA Generator

1. Check the connecting rod, large head cover, and bolts

Inspect the connecting rod using magnetic testing. Check for cracks in the large head cover, connecting rod screws or bolts.

If any visible marks can be seen through magnetic testing on the key parts of the connecting rod, the connecting rod must be replaced.

Attention: After the connecting rod has been processed and tested, it is not necessary to completely demagnetize and thoroughly clean it.

2. Check the hole diameter of the connecting rod at the large and small ends

1) Install the large end cap of the connecting rod of 1500kva Cummins generator onto the connecting rod and tighten the bolts according to the specified sequence and torque. When assembling the large end cap, be sure to note that the number on the center of the connecting rod must be the same as the number on the connecting rod cap.

2) Measure the large end aperture. Use an inner diameter dial gauge to measure the inner diameter of the hole within the range of 20 ° arc on each side of the joint surface with the connecting rod big end aperture. Measure the inner diameter of the hole at 90 ° from the joint surface.

The diameter of the connecting rod big end of the 6BT diesel engine is: for connecting rods with bolts and nuts, the diameter of the big end should be 83.114~83.139mm; For connecting rods with screws, the large end aperture should be 84.29-4.244mm.

The diameter of the connecting rod big end of the KTTA diesel engine is 114.343~114.369mm.

3) Measure the small end aperture. Measure the small end aperture with an inner micrometer.

6BT diesel engine connecting rod small end aperture: 50.825-61.024mm.

KTTA diesel engine connecting rod small end aperture: 60.985~61.024mm.

3. Check for damage to the I-shaped rod body

If there are scratches, scratches, or other damages deeper than 0.80mm on the I-shaped rod body, the connecting rod should be reimbursed.

4. Check the length, bending, and twisting of the connecting rod

The bending and twisting of the connecting rod can be inspected on a two bar tester. Before inspection, the inspection fixture should be calibrated by:

1) Use a standard connecting rod or a new connecting rod with a known length to calibrate the inspection fixture.

2) Select the appropriate piston pin hole spindle from a set of positioning mandrels and install it into the piston pin hole.

3) Then install the short shaft into the large head hole and tighten it so that it can be correctly positioned at the center of the large head hole.

4) Install the standard connecting rod into the inspection fixture. Loosen the knob and move the dial indicator bracket so that the contacts of the Longgang dial indicator touch the spindle of the small head hole. Tighten the bracket to fix the dial indicator and adjust the pointer of the dial indicator to the 0 position.

5) Remove the standard connecting rod from the experience fixture, flip it horizontally 180 °, and then transfer it into the calibration fixture. At this point, the pointer of the dial gauge should be at 0.

5. Check the connecting rod bolts and screw holes

If the tightening torque is too large, the connecting rod bolts may deform.

1) Check the minimum diameter of the bolt. For 6BT diesel engine connecting rod bolts, if the diameter is less than 13.72mm, they should be replaced.

2) When the threads of bolts or nuts are damaged, they should be scrapped.

3) The guiding aperture in the Longcheng screw hole. If the guide hole diameter of the connecting rod is greater than 15.88mm, it should be scrapped.

4) Check the rounded corners of the bolt boss. The bolt boss should have a rounded corner with a radius of 1.14-1.40mm, as shown in Figure 2-57. The maximum allowable cutting amount for grinding rounded corners is 1.587mm. All sharp corners on the boss should be removed after processing.