Torque Spec For Flywheel Bolts On Isx Cummins 251 Updated Fixed ★

The installation requires a specific multi-stage process and lubrication to ensure proper clamping force: 185 ft-lb (250 N·m) .

| Component | Torque | Notes | | :--- | :--- | :--- | | ISX Flywheel Bolt (251) – Standard | | Wet, 3 steps | | ISX Flywheel Bolt (251) – TTY | 265 lb-ft + 90° | Do not reuse | | Flywheel Housing to Block (251) | 44 lb-ft | M12 bolts | | Starter Motor Mounting Bolts | 65 lb-ft | Loctite 242 | | Clutch Pressure Plate (if equipped) | 55 lb-ft | Cross pattern | 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. The installation requires a specific multi-stage process and

: Ensure all debris and old lubricant are removed from both the bolt threads and the crankshaft mounting surface. The 251mm housing is standard on most over-the-road