Measurement
Install the connecting rod bearing cap (3) with connecting rod bearing shells (2) on the connecting rod.
Note. Do not change the connecting rod bearing cap and connecting rod during installation, and keep the mating surfaces clean
Note. Old bolts can be reused for testing.
Tighten 2 bolts to 13 Nm, then tighten +60°+15°.
The diameter of the connecting rod center is measured with an internal micrometer in positions I, II, and arithmetically. Formula and example for calculating the diameter of a connecting rod bearing: I + II + III.
I - 43, 026 mm.
II - 43, 027 mm.
III - 43, 031 mm.
129.084 mm: 3 = 43.028 mm.
The average inner diameter of the connecting rod bearing is 43.028 mm.
The connecting rod bearing journal diameter is measured with an external micrometer in positions I and II. Formula and example for calculating the diameter of the journal of the connecting rod bearing:
I + II / 2;
I - 42.977 mm + II - 42.985 mm.
85.962 mm: 2 = 42.981 mm.
The average diameter of the connecting rod bearing shaft journal is 42.981 mm.
Determine the clearance in the connecting rod bearing using the average inner diameter of the connecting rod bearing and the average diameter of the connecting rod bearing shaft journal.
The average inner diameter of the connecting rod bearing: 4.028 mm.
The average diameter of the neck of the connecting rod bearing shaft: 2.981 mm.
Connecting rod bearing clearance: 0.047 mm.
The design clearance in the connecting rod bearing is 0.047 mm in this example. The allowable clearance of the connecting rod bearing is from 0.013 mm to 0.061 mm.
Note. The check is carried out with a tool for measuring clearances in plain bearings.
Mark the installation position of the connecting rod bearing cap.
Disconnect the connecting rod bearing shells and connecting rod bearing cap by unscrewing the 2 mounting bolts.
Measure the connecting rod bearing clearance using a sleeve bearing clearance tool (plastic wire).
Note. The tool for measuring plain bearing clearances is available for various measuring ranges.
Cut the wire so that its length matches the width of the connecting rod bearing.
Lay the wire along the axis between the crankshaft main journal of the connecting rod bearing and the connecting rod bearing shell.
Install the connecting rod bearing cap
Note. To prevent the wire from breaking when removing the connecting rod bearing cap, remove the grease from the crankshaft journal and lightly grease the connecting rod bearing shell - do not turn the crankshaft.
Tighten the 2 bolts to a torque of 13 Nm, tighten by +60°and +15°.
Remove the connecting rod bearing cap, remove the 2 bolts.
Attention! Do not confuse decimal and metric scale information.
Measure the width of the flattened section of the plastic wire using a measuring scale.
Permissible clearance in the connecting rod bearing: from 0.013 mm to 0.061 mm.
Install the connecting rod bearing shell and connecting rod bearing cap.
Clean the crankshaft bearing journal and the connecting rod bearing shell.
Lightly grease the connecting rod bearing shells.
Tighten 2 bolts to 13 Nm and tighten +60°and +15°.
Attention! Always use M6.5 bolts. Use new bolts.
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