Torque Spec For Flywheel Bolts On Isx Cummins 251 Updated -

The term “251” refers to the SAE housing size (SAE #1) but specifically the flywheel mounting pattern. The ISX uses a heavy dual-mass or solid flywheel with a specific bolt circle. The 251mm housing is standard on most over-the-road ISX engines (Peterbilt, Kenworth, Freightliner). Getting the flywheel torque wrong is dangerous, but confusing it with the flexplate torque (used in motorhomes or industrial pumps) is catastrophic.

Cummins Isx Flywheel Bolt Torque Specs - sciphilconf.berkeley.edu torque spec for flywheel bolts on isx cummins 251 updated

Cummins released Service Bulletin (updated 2021) changing the procedure because: The term “251” refers to the SAE housing

| Step | Action | Value | |------|--------|-------| | 1 | Clean threads & crank flange holes (use a tap/chaser) | No debris | | 2 | Apply light oil to bolt threads & flange face | Do not over-saturate | | 3 | Hand-start all 14 bolts | Finger tight | | 4 | | 125 lb-ft | | 5 | Final Pass (Angle Control) | 90 degrees | Getting the flywheel torque wrong is dangerous, but