Measuring method of engine connecting rod

Measurement of backlash at the big end of connecting rod

Install crankshaft flywheel assembly and piston connecting rod assembly correctly according to engine assembly specifications. Measure the clearance between the big end of the connecting rod and the crankshaft. Replace the connecting rod if necessary.

1 dial indicator

2 connecting rod

3 Crankshaft

Connecting rod bushing clearance measurement

Measurement method:

(1) Place the plastic gap measuring strip on the crankshaft connecting rod journal in the axial direction.

(2) Install the connecting rod cover and tighten the bolts to the specified torque.

(3) Remove the connecting rod cover.

(4) Measure the thickness of the clearance measuring strip to obtain the fit clearance value of the crank pin. If the clearance exceeds the maximum value, replace the connecting rod bearing bush or grind the connecting rod journal, and use the bearing bush with reduced size to ensure that the clearance value meets the requirements.

Measurement of clearance of connecting rod head

Measure the inner diameter of each connecting rod small head in the X and Y directions shown in the above figure.

; According to the measured diameter of connecting rod small head, the fit clearance between connecting rod small head and piston pin is calculated. And check the matching of piston and connecting rod. Check the rotating torque as shown in the figure below. If the big head cannot fall by its own weight, replace the piston or piston pin.

Inspection of bending and twisting of connecting rod