Bolt Torque Information

[Poida]

The bolts tension specs used in the twincam engines are generally the same as the ones used for the SOHC engine. However, there may be some exceptions.

I have listed the SOHC G161Z and G180Z specs from genuine Isuzu engine manuals, also an image showing bolt diameters, thread pitch and metal the bolt is screwed into which you can cross check against the chart.

From the G161Z & G180Z Isuzu manual

Rod Cap Bolts:
G161Z- M8 bolt
4.5 kg.m
32.5 ftlbs
44.1 Nm
180Z & G200Z engines - M10 bolt
6.00 kg.m
43.4 ftlbs
58.9 Nm

Main Cap Bolts:
All engines
10.00 kg.m
72.3 ftlbs
98 Nm

Flywheel Bolts
All engines
9.50 kg.m
68.7 ftlbs
93.2 Nm

Front Crankshaft Pulley Bolt
All engines
12.00 kg.m
86.8 ftlbs
117.7 Nm

Cylinder Head Bolt
All engines
10.00 kg.m
72.3 ftlbs
98 Nm

Rocker Arm Shaft Bracket Bolts
All engines
2.2 kg.m
15.9 ftlbs
21.6 Nm

Camshaft Timing Gear
All engines
8.00 kg.m
57.9 ftlbs
78.4 Nm

Rocker Cover Bolts (all tinware can be at this setting)
All engines
0.50 kg.m
3.6 ftlbs (43.2 InchPound)
4.9 Nm

Sump Pan Bolts
All engines
0.50 kg.m
3.6 ftlbs (43.2 InchPound)
4.9 Nm

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