The ISX connecting rod uses a fracture-split design. The bolts are torque-to-yield (TTY) —they permanently stretch during installation. Never reuse ISX rod bolts. Always install new bolts with new bearings.
When rebuilding a Cummins ISX, the difference between a 500,000-mile engine and a 500-mile catastrophe often comes down to fastener management. The ISX does not use traditional "torque-only" bolts for its mains or rods. It uses Torque-to-Yield (TTY) or Angle Torque fasteners.
For new bolts, you are not tightening to a specific ft-lbs number; you are tightening to a specific clamp load achieved via yield. Here are the raw specs first, followed by the engineering logic. cummins isx main and rod bearings torque specs new
If you are rebuilding a Cummins ISX (Industrial Series eXperimental) engine—whether it’s the popular ISX15, ISX12, or the earlier EGR models—getting the torque specs for the main and rod bearings wrong is a guaranteed path to catastrophic failure. The ISX is a high-horsepower, high-torque workhorse found in Peterbilts, Kenworths, Freightliners, and Volvo trucks. Its composite block and complex joint designs require precision.
This article provides certified torque specifications for new main and rod bearings on a Cummins ISX. We will cover bolt tightening sequences, angle torquing (torque-to-yield), and critical steps that many online guides miss. The ISX connecting rod uses a fracture-split design
Disclaimer: This data is for informational purposes based on Cummins OEM guidelines. Always verify with your engine’s specific service manual (Cummins Quickserve). Torque specs may vary between ISX CM870, CM871, CM2250, and CM2350 models.
Torque specs are based on friction. If you torque a dry bolt to 95 lb-ft, the actual clamping force is 50% lower than a lubricated bolt. Always oil the threads and washer faces of new ISX bolts. Disclaimer: This data is for informational purposes based
| Component | Specification | | --- | --- | | Bolt type | M16 x 2.0 Property Class 10.9 (Wet torque) | | Lubrication | Clean 15W-40 engine oil (not assembly lube on threads) | | Step 1 Torque | 90 lb-ft (122 N·m) | | Step 2 Torque | 130 lb-ft (176 N·m) | | Step 3 (Final) | Angle-turn +90 degrees |
Note: On older ISX CM570/CM870, the final step may be +60 degrees instead of 90. Check your engine serial number.