Crankshaft and Connecting Rods
Install new bolts in reused connecting rods.
Dent both bolt head and bolt tip with a punch as shown.
Before tightening, use a point micrometer [A] to measure
the length of new connecting rod bolts and record the val-
ues to find the bolt stretch.
Connecting Rod [B]
Mark here with a punch [C].
Fit micrometer pins into punch marks [E].
Apply a small amount of molybdenum disulfide oil solution
to the following:
Threads of Nuts and Bolts
Seating Surfaces of Nuts and Con-rods
Tighten the big end nuts until the bolt elongation reaches
the length specified in the table.
Check the length [F] of the connecting rod bolts.
If the stretch is more than the usable range, the bolt has
stretched too much. An overelongated bolt may break in
Use the bolts
bolts with new
(2) Rotation Angle Method
If you don't have a point micrometer, you may tighten the
nuts using the "Rotation Angle Method".
Be sure to clean the bolts and nuts thoroughly with a high
-flash point solvent, because the new bolts and nuts are
treated with an anti-rust solution.
Clean the bolts and nuts in a well-ventilated area,
and take care that there is no spark or flame any-
where near the working area. This includes any ap-
pliance with a pilot light. Because of the danger
or highly flammable liquids, do not use gasoline or
low-flash point solvents to clean them.
Immediately dry the bolts and nuts with com-
pressed air after cleaning.
Clean and dry the bolts and nuts completely.
Usable Range of
0.24 ∼ 0.36 mm
(0.0094 ∼ 0.0142 in.)
0.20 ∼ 0.32 mm
(0.0079 ∼ 0.0126 in.)