Disassembly and Adjusting
Connecting Rod Bearings
d. If the main bearing clearances are checked with the
engine upright or on its side, the crankshaft must be
supported. Use a jack under an adjacent crankshaft
counterweight and hold the crankshaft against the crown
of the bearing. If the crankshaft is not supported, the
weight of the crankshaft will cause incorrect readings.
e. Put a piece of Plastigage on the crown of the bearing
half that is in the cap. Do not allow the Plastigage to
extend over the edge of the bearing.
f. Install the bearing cap using the correct torque-turn
specifications. Do not use an impact wrench. Be careful
not to dislodge the bearing when the cap is installed.
g. Do not turn the crankshaft with the Plastigage
h. Carefully remove the cap but do not remove the
Plastigage. Measure the width of the Plastigage while it
is in the bearing cap or on the crankshaft journal. Do this
by using the correct scale on the package. Record the
j. Remove the Plastigage before reinstalling the cap.
When using Plastigage, the readings can sometimes be
unclear. For example, all parts of the Plastigage are not
the same width. Measure the major widths to make sure
that they are within the specification range. Also,
experience has shown that when checking clearances
tighter than 0.10 mm (.004") the readings may be low by
0.013 to 0.025 mm (.0005 to .0010"). Out-of-round
journals can give faulty readings. Also, journal taper may
be indicated when one end of the Plastigage is wider
than the other.
For complete details concerning measuring bearing
clearances, see Engine Bearings And Crankshafts, Form
Use Plastigage (A) to check the connecting rod
Put Plastigage (A) on the connecting rod bearing.
Put clean engine oil on the threads of the rod bolts
and seat surfaces of the nuts.
When connecting rod caps are installed, make sure
the number on the side of the cap is next to and
respective with the number on the side of the