Connecting Rod Bearing Clearance, Micrometer Method - Mercury MerCruiser Service Manual

13. In a two pass sequence, tighten connecting rod cap screws to the specified torque.
Description
Connecting rod cap screw
14. Lightly tap each connecting rod assembly parallel to the crankpin to set side clearance.
15. Check rod bearing clearance using plastigauge method. Refer to Connecting Rod Bearing Clearance, Plastigauge
Method.
16. Measure all connecting rod side clearances between the connecting rod caps.
Description
Rod side clearance

Connecting Rod Bearing Clearance, Micrometer Method

IMPORTANT: The micrometer method is the preferred method of determining connecting rod bearing clearance.
IMPORTANT: All measurements should be taken when components are at room temperature.
Connecting rod bearings are of the precision insert type and do not use shims for adjustment. Replace the bearing if clearance
is found to be excessive. Service bearings are available in standard size and 0.001 in. and 0.002 in. undersized for use with
new and used standard size crankshafts. They are also available in 0.010 in. and 0.020 in. undersized for use with
reconditioned crankshafts.
1. Wipe both upper and lower connecting rod bearings clean with a soft cloth.
2. Install the upper and lower connecting rod bearings.
3. Install the bearing cap.
4. In a two step sequence, tighten the bearing cap screws to the specified torque.
Description
Bearing cap screws
5. Use an inside dial indicator to measure the connecting rod bearing inside diameter and out of round and taper. Measure in
several places approximately 90° apart and average the measurements.
90-8M0099748 eng DECEMBER 2015
First
Final
Measuring connecting rod side clearance
First
Final
© 2016 Mercury Marine
Engine Inspection and Assembly
Nm lb‑in.
25 –
+90°
6408
6.2 Liter (377 cid)
0.312–0.588 mm (0.013–0.023 in.)
Nm lb‑in.
25 –
+90°
lb‑ft
18.4
lb‑ft
18.4
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